diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index e7562934..0c2ecec6 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.19.0"
+  ".": "0.20.0"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c16b34ce..6c745f0d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,33 @@
 # Changelog
 
+## 0.20.0 (2025-01-07)
+
+Full Changelog: [v0.19.0...v0.20.0](https://github.com/orbcorp/orb-java/compare/v0.19.0...v0.20.0)
+
+### Features
+
+* **client:** add various convenience setters to models ([#184](https://github.com/orbcorp/orb-java/issues/184)) ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+* **client:** allow setting arbitrary JSON for top-level body params ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+* **client:** expose getters for `JsonField` of body params ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+
+
+### Bug Fixes
+
+* **client:** consistently throw on omitting required fields ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+* **client:** convert `JsonField` containing list type to mutable in builder ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+
+
+### Documentation
+
+* add params class javadocs ([#182](https://github.com/orbcorp/orb-java/issues/182)) ([e98658d](https://github.com/orbcorp/orb-java/commit/e98658d54e9ef45334ae98fe2901a2db1574a900))
+
+
+### Styles
+
+* **internal:** explicitly add some method return types ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+* **internal:** move headers and query params setters below others ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+* **internal:** simplify existing convenience setters on params ([5a7e67f](https://github.com/orbcorp/orb-java/commit/5a7e67f4aff5cd005c04148c72c4f9dbb1f65449))
+
 ## 0.19.0 (2025-01-06)
 
 Full Changelog: [v0.18.0...v0.19.0](https://github.com/orbcorp/orb-java/compare/v0.18.0...v0.19.0)
diff --git a/README.md b/README.md
index 6654207a..f98dc8ea 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 <!-- x-release-please-start-version -->
 
-[![Maven Central](https://img.shields.io/maven-central/v/com.withorb.api/orb-java)](https://central.sonatype.com/artifact/com.withorb.api/orb-java/0.19.0)
+[![Maven Central](https://img.shields.io/maven-central/v/com.withorb.api/orb-java)](https://central.sonatype.com/artifact/com.withorb.api/orb-java/0.20.0)
 
 <!-- x-release-please-end -->
 
@@ -25,7 +25,7 @@ The REST API documentation can be found on [docs.withorb.com](https://docs.with
 <!-- x-release-please-start-version -->
 
 ```kotlin
-implementation("com.withorb.api:orb-java:0.19.0")
+implementation("com.withorb.api:orb-java:0.20.0")
 ```
 
 #### Maven
@@ -34,7 +34,7 @@ implementation("com.withorb.api:orb-java:0.19.0")
 <dependency>
     <groupId>com.withorb.api</groupId>
     <artifactId>orb-java</artifactId>
-    <version>0.19.0</version>
+    <version>0.20.0</version>
 </dependency>
 ```
 
diff --git a/build.gradle.kts b/build.gradle.kts
index 64a0a083..2cba1d15 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -4,7 +4,7 @@ plugins {
 
 allprojects {
     group = "com.withorb.api"
-    version = "0.19.0" // x-release-please-version
+    version = "0.20.0" // x-release-please-version
 }
 
 
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/core/ClientOptions.kt b/orb-java-core/src/main/kotlin/com/withorb/api/core/ClientOptions.kt
index 39bcc89e..13987e4d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/core/ClientOptions.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/core/ClientOptions.kt
@@ -72,6 +72,19 @@ private constructor(
 
         fun baseUrl(baseUrl: String) = apply { this.baseUrl = baseUrl }
 
+        fun responseValidation(responseValidation: Boolean) = apply {
+            this.responseValidation = responseValidation
+        }
+
+        fun maxRetries(maxRetries: Int) = apply { this.maxRetries = maxRetries }
+
+        fun apiKey(apiKey: String) = apply { this.apiKey = apiKey }
+
+        fun webhookSecret(webhookSecret: String?) = apply { this.webhookSecret = webhookSecret }
+
+        fun webhookSecret(webhookSecret: Optional<String>) =
+            webhookSecret(webhookSecret.orElse(null))
+
         fun headers(headers: Headers) = apply {
             this.headers.clear()
             putAllHeaders(headers)
@@ -152,19 +165,6 @@ private constructor(
 
         fun removeAllQueryParams(keys: Set<String>) = apply { queryParams.removeAll(keys) }
 
-        fun responseValidation(responseValidation: Boolean) = apply {
-            this.responseValidation = responseValidation
-        }
-
-        fun maxRetries(maxRetries: Int) = apply { this.maxRetries = maxRetries }
-
-        fun apiKey(apiKey: String) = apply { this.apiKey = apiKey }
-
-        fun webhookSecret(webhookSecret: String?) = apply { this.webhookSecret = webhookSecret }
-
-        fun webhookSecret(webhookSecret: Optional<String>) =
-            webhookSecret(webhookSecret.orElse(null))
-
         fun fromEnv() = apply {
             System.getenv("ORB_API_KEY")?.let { apiKey(it) }
             System.getenv("ORB_WEBHOOK_SECRET")?.let { webhookSecret(it) }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Alert.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Alert.kt
index 04d2bcbd..9f81d149 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Alert.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Alert.kt
@@ -89,34 +89,40 @@ private constructor(
     fun type(): Type = type.getRequired("type")
 
     /** Also referred to as alert_id in this documentation. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The creation time of the resource in Orb. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /** The name of the currency the credit balance or invoice cost is denominated in. */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /** The customer the alert applies to. */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /** Whether the alert is enabled or disabled. */
-    @JsonProperty("enabled") @ExcludeMissing fun _enabled() = enabled
+    @JsonProperty("enabled") @ExcludeMissing fun _enabled(): JsonField<Boolean> = enabled
 
     /** The metric the alert applies to. */
-    @JsonProperty("metric") @ExcludeMissing fun _metric() = metric
+    @JsonProperty("metric") @ExcludeMissing fun _metric(): JsonField<Metric> = metric
 
     /** The plan the alert applies to. */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The subscription the alert applies to. */
-    @JsonProperty("subscription") @ExcludeMissing fun _subscription() = subscription
+    @JsonProperty("subscription")
+    @ExcludeMissing
+    fun _subscription(): JsonField<Subscription> = subscription
 
     /** The thresholds that define the conditions under which the alert will be triggered. */
-    @JsonProperty("thresholds") @ExcludeMissing fun _thresholds() = thresholds
+    @JsonProperty("thresholds")
+    @ExcludeMissing
+    fun _thresholds(): JsonField<List<Threshold>> = thresholds
 
     /** The type of alert. This must be a valid alert type. */
-    @JsonProperty("type") @ExcludeMissing fun _type() = type
+    @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -149,16 +155,16 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var enabled: JsonField<Boolean> = JsonMissing.of()
-        private var metric: JsonField<Metric> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var subscription: JsonField<Subscription> = JsonMissing.of()
-        private var thresholds: JsonField<List<Threshold>> = JsonMissing.of()
-        private var type: JsonField<Type> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currency: JsonField<String>? = null
+        private var customer: JsonField<Customer>? = null
+        private var enabled: JsonField<Boolean>? = null
+        private var metric: JsonField<Metric>? = null
+        private var plan: JsonField<Plan>? = null
+        private var subscription: JsonField<Subscription>? = null
+        private var thresholds: JsonField<MutableList<Threshold>>? = null
+        private var type: JsonField<Type>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -171,7 +177,7 @@ private constructor(
             metric = alert.metric
             plan = alert.plan
             subscription = alert.subscription
-            thresholds = alert.thresholds
+            thresholds = alert.thresholds.map { it.toMutableList() }
             type = alert.type
             additionalProperties = alert.additionalProperties.toMutableMap()
         }
@@ -189,13 +195,19 @@ private constructor(
         fun createdAt(createdAt: JsonField<OffsetDateTime>) = apply { this.createdAt = createdAt }
 
         /** The name of the currency the credit balance or invoice cost is denominated in. */
-        fun currency(currency: String) = currency(JsonField.of(currency))
+        fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
+
+        /** The name of the currency the credit balance or invoice cost is denominated in. */
+        fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
         /** The name of the currency the credit balance or invoice cost is denominated in. */
         fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
         /** The customer the alert applies to. */
-        fun customer(customer: Customer) = customer(JsonField.of(customer))
+        fun customer(customer: Customer?) = customer(JsonField.ofNullable(customer))
+
+        /** The customer the alert applies to. */
+        fun customer(customer: Optional<Customer>) = customer(customer.orElse(null))
 
         /** The customer the alert applies to. */
         fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
@@ -207,19 +219,30 @@ private constructor(
         fun enabled(enabled: JsonField<Boolean>) = apply { this.enabled = enabled }
 
         /** The metric the alert applies to. */
-        fun metric(metric: Metric) = metric(JsonField.of(metric))
+        fun metric(metric: Metric?) = metric(JsonField.ofNullable(metric))
+
+        /** The metric the alert applies to. */
+        fun metric(metric: Optional<Metric>) = metric(metric.orElse(null))
 
         /** The metric the alert applies to. */
         fun metric(metric: JsonField<Metric>) = apply { this.metric = metric }
 
         /** The plan the alert applies to. */
-        fun plan(plan: Plan) = plan(JsonField.of(plan))
+        fun plan(plan: Plan?) = plan(JsonField.ofNullable(plan))
+
+        /** The plan the alert applies to. */
+        fun plan(plan: Optional<Plan>) = plan(plan.orElse(null))
 
         /** The plan the alert applies to. */
         fun plan(plan: JsonField<Plan>) = apply { this.plan = plan }
 
         /** The subscription the alert applies to. */
-        fun subscription(subscription: Subscription) = subscription(JsonField.of(subscription))
+        fun subscription(subscription: Subscription?) =
+            subscription(JsonField.ofNullable(subscription))
+
+        /** The subscription the alert applies to. */
+        fun subscription(subscription: Optional<Subscription>) =
+            subscription(subscription.orElse(null))
 
         /** The subscription the alert applies to. */
         fun subscription(subscription: JsonField<Subscription>) = apply {
@@ -227,11 +250,28 @@ private constructor(
         }
 
         /** The thresholds that define the conditions under which the alert will be triggered. */
-        fun thresholds(thresholds: List<Threshold>) = thresholds(JsonField.of(thresholds))
+        fun thresholds(thresholds: List<Threshold>?) = thresholds(JsonField.ofNullable(thresholds))
+
+        /** The thresholds that define the conditions under which the alert will be triggered. */
+        fun thresholds(thresholds: Optional<List<Threshold>>) = thresholds(thresholds.orElse(null))
 
         /** The thresholds that define the conditions under which the alert will be triggered. */
         fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
-            this.thresholds = thresholds
+            this.thresholds = thresholds.map { it.toMutableList() }
+        }
+
+        /** The thresholds that define the conditions under which the alert will be triggered. */
+        fun addThreshold(threshold: Threshold) = apply {
+            thresholds =
+                (thresholds ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(threshold)
+                }
         }
 
         /** The type of alert. This must be a valid alert type. */
@@ -261,16 +301,17 @@ private constructor(
 
         fun build(): Alert =
             Alert(
-                id,
-                createdAt,
-                currency,
-                customer,
-                enabled,
-                metric,
-                plan,
-                subscription,
-                thresholds.map { it.toImmutable() },
-                type,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(enabled) { "`enabled` is required but was not set" },
+                checkNotNull(metric) { "`metric` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(subscription) { "`subscription` is required but was not set" },
+                checkNotNull(thresholds) { "`thresholds` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(type) { "`type` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -293,11 +334,11 @@ private constructor(
         fun externalCustomerId(): Optional<String> =
             Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("external_customer_id")
         @ExcludeMissing
-        fun _externalCustomerId() = externalCustomerId
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -322,8 +363,8 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalCustomerId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -337,8 +378,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun externalCustomerId(externalCustomerId: String) =
-                externalCustomerId(JsonField.of(externalCustomerId))
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+            fun externalCustomerId(externalCustomerId: Optional<String>) =
+                externalCustomerId(externalCustomerId.orElse(null))
 
             fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                 this.externalCustomerId = externalCustomerId
@@ -365,8 +409,10 @@ private constructor(
 
             fun build(): Customer =
                 Customer(
-                    id,
-                    externalCustomerId,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalCustomerId) {
+                        "`externalCustomerId` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -401,7 +447,7 @@ private constructor(
 
         fun id(): String = id.getRequired("id")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -425,7 +471,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -457,7 +503,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Metric = Metric(id, additionalProperties.toImmutable())
+            fun build(): Metric =
+                Metric(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
@@ -510,18 +560,22 @@ private constructor(
 
         fun planVersion(): String = planVersion.getRequired("plan_version")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
-        @JsonProperty("external_plan_id") @ExcludeMissing fun _externalPlanId() = externalPlanId
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_version") @ExcludeMissing fun _planVersion() = planVersion
+        @JsonProperty("plan_version")
+        @ExcludeMissing
+        fun _planVersion(): JsonField<String> = planVersion
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -548,10 +602,10 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalPlanId: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planVersion: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalPlanId: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var planVersion: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -563,7 +617,9 @@ private constructor(
                 additionalProperties = plan.additionalProperties.toMutableMap()
             }
 
-            fun id(id: String) = id(JsonField.of(id))
+            fun id(id: String?) = id(JsonField.ofNullable(id))
+
+            fun id(id: Optional<String>) = id(id.orElse(null))
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
@@ -572,8 +628,16 @@ private constructor(
              * alias for this Plan. Use this field to identify a plan by an existing identifier in
              * your system.
              */
-            fun externalPlanId(externalPlanId: String) =
-                externalPlanId(JsonField.of(externalPlanId))
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
+
+            /**
+             * An optional user-defined ID for this plan resource, used throughout the system as an
+             * alias for this Plan. Use this field to identify a plan by an existing identifier in
+             * your system.
+             */
+            fun externalPlanId(externalPlanId: Optional<String>) =
+                externalPlanId(externalPlanId.orElse(null))
 
             /**
              * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -584,7 +648,9 @@ private constructor(
                 this.externalPlanId = externalPlanId
             }
 
-            fun name(name: String) = name(JsonField.of(name))
+            fun name(name: String?) = name(JsonField.ofNullable(name))
+
+            fun name(name: Optional<String>) = name(name.orElse(null))
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
@@ -615,10 +681,10 @@ private constructor(
 
             fun build(): Plan =
                 Plan(
-                    id,
-                    externalPlanId,
-                    name,
-                    planVersion,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalPlanId) { "`externalPlanId` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planVersion) { "`planVersion` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -653,7 +719,7 @@ private constructor(
 
         fun id(): String = id.getRequired("id")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -677,7 +743,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -709,7 +775,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Subscription = Subscription(id, additionalProperties.toImmutable())
+            fun build(): Subscription =
+                Subscription(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
@@ -753,7 +823,7 @@ private constructor(
          * or below this value. For usage and cost alerts, the alert will fire at or above this
          * value.
          */
-        @JsonProperty("value") @ExcludeMissing fun _value() = value
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<Double> = value
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -777,7 +847,7 @@ private constructor(
 
         class Builder {
 
-            private var value: JsonField<Double> = JsonMissing.of()
+            private var value: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -819,7 +889,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Threshold = Threshold(value, additionalProperties.toImmutable())
+            fun build(): Threshold =
+                Threshold(
+                    checkNotNull(value) { "`value` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForCustomerParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForCustomerParams.kt
index 1e152e87..1cac4a23 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForCustomerParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForCustomerParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,14 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint creates a new alert to monitor a customer's credit balance. There are three types
+ * of alerts that can be scoped to customers: `credit_balance_depleted`, `credit_balance_dropped`,
+ * and `credit_balance_recovered`. Customers can have a maximum of one of each type of alert per
+ * [credit balance currency](https://docs.withorb.com/guides/product-catalog/prepurchase).
+ * `credit_balance_dropped` alerts require a list of thresholds to be provided while
+ * `credit_balance_depleted` and `credit_balance_recovered` alerts do not require thresholds.
+ */
 class AlertCreateForCustomerParams
 constructor(
     private val customerId: String,
@@ -38,12 +47,21 @@ constructor(
     /** The thresholds that define the values at which the alert will be triggered. */
     fun thresholds(): Optional<List<Threshold>> = body.thresholds()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The case sensitive currency or custom pricing unit to use for this alert. */
+    fun _currency(): JsonField<String> = body._currency()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The type of alert to create. This must be a valid alert type. */
+    fun _type(): JsonField<Type> = body._type()
+
+    /** The thresholds that define the values at which the alert will be triggered. */
+    fun _thresholds(): JsonField<List<Threshold>> = body._thresholds()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): AlertCreateForCustomerBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -61,27 +79,53 @@ constructor(
     class AlertCreateForCustomerBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("thresholds") private val thresholds: List<Threshold>?,
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        private val thresholds: JsonField<List<Threshold>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The case sensitive currency or custom pricing unit to use for this alert. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The type of alert to create. This must be a valid alert type. */
+        fun type(): Type = type.getRequired("type")
+
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(): Optional<List<Threshold>> =
+            Optional.ofNullable(thresholds.getNullable("thresholds"))
+
+        /** The case sensitive currency or custom pricing unit to use for this alert. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The type of alert to create. This must be a valid alert type. */
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
         /** The thresholds that define the values at which the alert will be triggered. */
         @JsonProperty("thresholds")
-        fun thresholds(): Optional<List<Threshold>> = Optional.ofNullable(thresholds)
+        @ExcludeMissing
+        fun _thresholds(): JsonField<List<Threshold>> = thresholds
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AlertCreateForCustomerBody = apply {
+            if (!validated) {
+                currency()
+                type()
+                thresholds().map { it.forEach { it.validate() } }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -91,38 +135,57 @@ constructor(
 
         class Builder {
 
-            private var currency: String? = null
-            private var type: Type? = null
-            private var thresholds: MutableList<Threshold>? = null
+            private var currency: JsonField<String>? = null
+            private var type: JsonField<Type>? = null
+            private var thresholds: JsonField<MutableList<Threshold>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(alertCreateForCustomerBody: AlertCreateForCustomerBody) = apply {
                 currency = alertCreateForCustomerBody.currency
                 type = alertCreateForCustomerBody.type
-                thresholds = alertCreateForCustomerBody.thresholds?.toMutableList()
+                thresholds = alertCreateForCustomerBody.thresholds.map { it.toMutableList() }
                 additionalProperties =
                     alertCreateForCustomerBody.additionalProperties.toMutableMap()
             }
 
             /** The case sensitive currency or custom pricing unit to use for this alert. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** The case sensitive currency or custom pricing unit to use for this alert. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The type of alert to create. This must be a valid alert type. */
+            fun type(type: Type) = type(JsonField.of(type))
 
             /** The type of alert to create. This must be a valid alert type. */
-            fun type(type: Type) = apply { this.type = type }
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
             /** The thresholds that define the values at which the alert will be triggered. */
-            fun thresholds(thresholds: List<Threshold>?) = apply {
-                this.thresholds = thresholds?.toMutableList()
-            }
+            fun thresholds(thresholds: List<Threshold>?) =
+                thresholds(JsonField.ofNullable(thresholds))
 
             /** The thresholds that define the values at which the alert will be triggered. */
             fun thresholds(thresholds: Optional<List<Threshold>>) =
                 thresholds(thresholds.orElse(null))
 
+            /** The thresholds that define the values at which the alert will be triggered. */
+            fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+                this.thresholds = thresholds.map { it.toMutableList() }
+            }
+
             /** The thresholds that define the values at which the alert will be triggered. */
             fun addThreshold(threshold: Threshold) = apply {
-                thresholds = (thresholds ?: mutableListOf()).apply { add(threshold) }
+                thresholds =
+                    (thresholds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(threshold)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -148,7 +211,7 @@ constructor(
                 AlertCreateForCustomerBody(
                     checkNotNull(currency) { "`currency` is required but was not set" },
                     checkNotNull(type) { "`type` is required but was not set" },
-                    thresholds?.toImmutable(),
+                    (thresholds ?: JsonMissing.of()).map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -199,18 +262,48 @@ constructor(
         /** The case sensitive currency or custom pricing unit to use for this alert. */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /** The case sensitive currency or custom pricing unit to use for this alert. */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** The type of alert to create. This must be a valid alert type. */
         fun type(type: Type) = apply { body.type(type) }
 
+        /** The type of alert to create. This must be a valid alert type. */
+        fun type(type: JsonField<Type>) = apply { body.type(type) }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: List<Threshold>?) = apply { body.thresholds(thresholds) }
 
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: Optional<List<Threshold>>) = thresholds(thresholds.orElse(null))
 
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+            body.thresholds(thresholds)
+        }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun addThreshold(threshold: Threshold) = apply { body.addThreshold(threshold) }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -309,25 +402,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): AlertCreateForCustomerParams =
             AlertCreateForCustomerParams(
                 checkNotNull(customerId) { "`customerId` is required but was not set" },
@@ -417,7 +491,9 @@ constructor(
     class Threshold
     @JsonCreator
     private constructor(
-        @JsonProperty("value") private val value: Double,
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<Double> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -427,12 +503,28 @@ constructor(
          * or below this value. For usage and cost alerts, the alert will fire at or above this
          * value.
          */
-        @JsonProperty("value") fun value(): Double = value
+        fun value(): Double = value.getRequired("value")
+
+        /**
+         * The value at which an alert will fire. For credit balance alerts, the alert will fire at
+         * or below this value. For usage and cost alerts, the alert will fire at or above this
+         * value.
+         */
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<Double> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Threshold = apply {
+            if (!validated) {
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -442,7 +534,7 @@ constructor(
 
         class Builder {
 
-            private var value: Double? = null
+            private var value: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -456,7 +548,14 @@ constructor(
              * at or below this value. For usage and cost alerts, the alert will fire at or above
              * this value.
              */
-            fun value(value: Double) = apply { this.value = value }
+            fun value(value: Double) = value(JsonField.of(value))
+
+            /**
+             * The value at which an alert will fire. For credit balance alerts, the alert will fire
+             * at or below this value. For usage and cost alerts, the alert will fire at or above
+             * this value.
+             */
+            fun value(value: JsonField<Double>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForExternalCustomerParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForExternalCustomerParams.kt
index 5c144763..37f68a25 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForExternalCustomerParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForExternalCustomerParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,14 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint creates a new alert to monitor a customer's credit balance. There are three types
+ * of alerts that can be scoped to customers: `credit_balance_depleted`, `credit_balance_dropped`,
+ * and `credit_balance_recovered`. Customers can have a maximum of one of each type of alert per
+ * [credit balance currency](https://docs.withorb.com/guides/product-catalog/prepurchase).
+ * `credit_balance_dropped` alerts require a list of thresholds to be provided while
+ * `credit_balance_depleted` and `credit_balance_recovered` alerts do not require thresholds.
+ */
 class AlertCreateForExternalCustomerParams
 constructor(
     private val externalCustomerId: String,
@@ -38,12 +47,21 @@ constructor(
     /** The thresholds that define the values at which the alert will be triggered. */
     fun thresholds(): Optional<List<Threshold>> = body.thresholds()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The case sensitive currency or custom pricing unit to use for this alert. */
+    fun _currency(): JsonField<String> = body._currency()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The type of alert to create. This must be a valid alert type. */
+    fun _type(): JsonField<Type> = body._type()
+
+    /** The thresholds that define the values at which the alert will be triggered. */
+    fun _thresholds(): JsonField<List<Threshold>> = body._thresholds()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): AlertCreateForExternalCustomerBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -61,27 +79,53 @@ constructor(
     class AlertCreateForExternalCustomerBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("thresholds") private val thresholds: List<Threshold>?,
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        private val thresholds: JsonField<List<Threshold>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The case sensitive currency or custom pricing unit to use for this alert. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The type of alert to create. This must be a valid alert type. */
+        fun type(): Type = type.getRequired("type")
+
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(): Optional<List<Threshold>> =
+            Optional.ofNullable(thresholds.getNullable("thresholds"))
+
+        /** The case sensitive currency or custom pricing unit to use for this alert. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The type of alert to create. This must be a valid alert type. */
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
         /** The thresholds that define the values at which the alert will be triggered. */
         @JsonProperty("thresholds")
-        fun thresholds(): Optional<List<Threshold>> = Optional.ofNullable(thresholds)
+        @ExcludeMissing
+        fun _thresholds(): JsonField<List<Threshold>> = thresholds
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AlertCreateForExternalCustomerBody = apply {
+            if (!validated) {
+                currency()
+                type()
+                thresholds().map { it.forEach { it.validate() } }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -91,9 +135,9 @@ constructor(
 
         class Builder {
 
-            private var currency: String? = null
-            private var type: Type? = null
-            private var thresholds: MutableList<Threshold>? = null
+            private var currency: JsonField<String>? = null
+            private var type: JsonField<Type>? = null
+            private var thresholds: JsonField<MutableList<Threshold>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -102,29 +146,49 @@ constructor(
             ) = apply {
                 currency = alertCreateForExternalCustomerBody.currency
                 type = alertCreateForExternalCustomerBody.type
-                thresholds = alertCreateForExternalCustomerBody.thresholds?.toMutableList()
+                thresholds =
+                    alertCreateForExternalCustomerBody.thresholds.map { it.toMutableList() }
                 additionalProperties =
                     alertCreateForExternalCustomerBody.additionalProperties.toMutableMap()
             }
 
             /** The case sensitive currency or custom pricing unit to use for this alert. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** The case sensitive currency or custom pricing unit to use for this alert. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The type of alert to create. This must be a valid alert type. */
+            fun type(type: Type) = type(JsonField.of(type))
 
             /** The type of alert to create. This must be a valid alert type. */
-            fun type(type: Type) = apply { this.type = type }
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
             /** The thresholds that define the values at which the alert will be triggered. */
-            fun thresholds(thresholds: List<Threshold>?) = apply {
-                this.thresholds = thresholds?.toMutableList()
-            }
+            fun thresholds(thresholds: List<Threshold>?) =
+                thresholds(JsonField.ofNullable(thresholds))
 
             /** The thresholds that define the values at which the alert will be triggered. */
             fun thresholds(thresholds: Optional<List<Threshold>>) =
                 thresholds(thresholds.orElse(null))
 
+            /** The thresholds that define the values at which the alert will be triggered. */
+            fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+                this.thresholds = thresholds.map { it.toMutableList() }
+            }
+
             /** The thresholds that define the values at which the alert will be triggered. */
             fun addThreshold(threshold: Threshold) = apply {
-                thresholds = (thresholds ?: mutableListOf()).apply { add(threshold) }
+                thresholds =
+                    (thresholds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(threshold)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -150,7 +214,7 @@ constructor(
                 AlertCreateForExternalCustomerBody(
                     checkNotNull(currency) { "`currency` is required but was not set" },
                     checkNotNull(type) { "`type` is required but was not set" },
-                    thresholds?.toImmutable(),
+                    (thresholds ?: JsonMissing.of()).map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -207,18 +271,48 @@ constructor(
         /** The case sensitive currency or custom pricing unit to use for this alert. */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /** The case sensitive currency or custom pricing unit to use for this alert. */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** The type of alert to create. This must be a valid alert type. */
         fun type(type: Type) = apply { body.type(type) }
 
+        /** The type of alert to create. This must be a valid alert type. */
+        fun type(type: JsonField<Type>) = apply { body.type(type) }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: List<Threshold>?) = apply { body.thresholds(thresholds) }
 
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: Optional<List<Threshold>>) = thresholds(thresholds.orElse(null))
 
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+            body.thresholds(thresholds)
+        }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun addThreshold(threshold: Threshold) = apply { body.addThreshold(threshold) }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -317,25 +411,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): AlertCreateForExternalCustomerParams =
             AlertCreateForExternalCustomerParams(
                 checkNotNull(externalCustomerId) {
@@ -427,7 +502,9 @@ constructor(
     class Threshold
     @JsonCreator
     private constructor(
-        @JsonProperty("value") private val value: Double,
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<Double> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -437,12 +514,28 @@ constructor(
          * or below this value. For usage and cost alerts, the alert will fire at or above this
          * value.
          */
-        @JsonProperty("value") fun value(): Double = value
+        fun value(): Double = value.getRequired("value")
+
+        /**
+         * The value at which an alert will fire. For credit balance alerts, the alert will fire at
+         * or below this value. For usage and cost alerts, the alert will fire at or above this
+         * value.
+         */
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<Double> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Threshold = apply {
+            if (!validated) {
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -452,7 +545,7 @@ constructor(
 
         class Builder {
 
-            private var value: Double? = null
+            private var value: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -466,7 +559,14 @@ constructor(
              * at or below this value. For usage and cost alerts, the alert will fire at or above
              * this value.
              */
-            fun value(value: Double) = apply { this.value = value }
+            fun value(value: Double) = value(JsonField.of(value))
+
+            /**
+             * The value at which an alert will fire. For credit balance alerts, the alert will fire
+             * at or below this value. For usage and cost alerts, the alert will fire at or above
+             * this value.
+             */
+            fun value(value: JsonField<Double>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForSubscriptionParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForSubscriptionParams.kt
index daa10ea4..373e5d47 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForSubscriptionParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertCreateForSubscriptionParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,18 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to create alerts at the subscription level.
+ *
+ * Subscription level alerts can be one of two types: `usage_exceeded` or `cost_exceeded`. A
+ * `usage_exceeded` alert is scoped to a particular metric and is triggered when the usage of that
+ * metric exceeds predefined thresholds during the current billing cycle. A `cost_exceeded` alert is
+ * triggered when the total amount due during the current billing cycle surpasses predefined
+ * thresholds. `cost_exceeded` alerts do not include burndown of pre-purchase credits. Each
+ * subscription can have one `cost_exceeded` alert and one `usage_exceeded` alert per metric that is
+ * a part of the subscription. Alerts are triggered based on usage or cost conditions met during the
+ * current billing cycle.
+ */
 class AlertCreateForSubscriptionParams
 constructor(
     private val subscriptionId: String,
@@ -38,12 +51,21 @@ constructor(
     /** The metric to track usage for. */
     fun metricId(): Optional<String> = body.metricId()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The thresholds that define the values at which the alert will be triggered. */
+    fun _thresholds(): JsonField<List<Threshold>> = body._thresholds()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The type of alert to create. This must be a valid alert type. */
+    fun _type(): JsonField<Type> = body._type()
+
+    /** The metric to track usage for. */
+    fun _metricId(): JsonField<String> = body._metricId()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): AlertCreateForSubscriptionBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -61,26 +83,52 @@ constructor(
     class AlertCreateForSubscriptionBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("thresholds") private val thresholds: List<Threshold>,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("metric_id") private val metricId: String?,
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        private val thresholds: JsonField<List<Threshold>> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("metric_id")
+        @ExcludeMissing
+        private val metricId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The thresholds that define the values at which the alert will be triggered. */
-        @JsonProperty("thresholds") fun thresholds(): List<Threshold> = thresholds
+        fun thresholds(): List<Threshold> = thresholds.getRequired("thresholds")
 
         /** The type of alert to create. This must be a valid alert type. */
-        @JsonProperty("type") fun type(): Type = type
+        fun type(): Type = type.getRequired("type")
 
         /** The metric to track usage for. */
-        @JsonProperty("metric_id") fun metricId(): Optional<String> = Optional.ofNullable(metricId)
+        fun metricId(): Optional<String> = Optional.ofNullable(metricId.getNullable("metric_id"))
+
+        /** The thresholds that define the values at which the alert will be triggered. */
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        fun _thresholds(): JsonField<List<Threshold>> = thresholds
+
+        /** The type of alert to create. This must be a valid alert type. */
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
+
+        /** The metric to track usage for. */
+        @JsonProperty("metric_id") @ExcludeMissing fun _metricId(): JsonField<String> = metricId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AlertCreateForSubscriptionBody = apply {
+            if (!validated) {
+                thresholds().forEach { it.validate() }
+                type()
+                metricId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -90,15 +138,16 @@ constructor(
 
         class Builder {
 
-            private var thresholds: MutableList<Threshold>? = null
-            private var type: Type? = null
-            private var metricId: String? = null
+            private var thresholds: JsonField<MutableList<Threshold>>? = null
+            private var type: JsonField<Type>? = null
+            private var metricId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(alertCreateForSubscriptionBody: AlertCreateForSubscriptionBody) =
                 apply {
-                    thresholds = alertCreateForSubscriptionBody.thresholds.toMutableList()
+                    thresholds =
+                        alertCreateForSubscriptionBody.thresholds.map { it.toMutableList() }
                     type = alertCreateForSubscriptionBody.type
                     metricId = alertCreateForSubscriptionBody.metricId
                     additionalProperties =
@@ -106,24 +155,42 @@ constructor(
                 }
 
             /** The thresholds that define the values at which the alert will be triggered. */
-            fun thresholds(thresholds: List<Threshold>) = apply {
-                this.thresholds = thresholds.toMutableList()
+            fun thresholds(thresholds: List<Threshold>) = thresholds(JsonField.of(thresholds))
+
+            /** The thresholds that define the values at which the alert will be triggered. */
+            fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+                this.thresholds = thresholds.map { it.toMutableList() }
             }
 
             /** The thresholds that define the values at which the alert will be triggered. */
             fun addThreshold(threshold: Threshold) = apply {
-                thresholds = (thresholds ?: mutableListOf()).apply { add(threshold) }
+                thresholds =
+                    (thresholds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(threshold)
+                    }
             }
 
             /** The type of alert to create. This must be a valid alert type. */
-            fun type(type: Type) = apply { this.type = type }
+            fun type(type: Type) = type(JsonField.of(type))
+
+            /** The type of alert to create. This must be a valid alert type. */
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
             /** The metric to track usage for. */
-            fun metricId(metricId: String?) = apply { this.metricId = metricId }
+            fun metricId(metricId: String?) = metricId(JsonField.ofNullable(metricId))
 
             /** The metric to track usage for. */
             fun metricId(metricId: Optional<String>) = metricId(metricId.orElse(null))
 
+            /** The metric to track usage for. */
+            fun metricId(metricId: JsonField<String>) = apply { this.metricId = metricId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -146,7 +213,7 @@ constructor(
             fun build(): AlertCreateForSubscriptionBody =
                 AlertCreateForSubscriptionBody(
                     checkNotNull(thresholds) { "`thresholds` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     checkNotNull(type) { "`type` is required but was not set" },
                     metricId,
                     additionalProperties.toImmutable(),
@@ -202,18 +269,48 @@ constructor(
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: List<Threshold>) = apply { body.thresholds(thresholds) }
 
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+            body.thresholds(thresholds)
+        }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun addThreshold(threshold: Threshold) = apply { body.addThreshold(threshold) }
 
         /** The type of alert to create. This must be a valid alert type. */
         fun type(type: Type) = apply { body.type(type) }
 
+        /** The type of alert to create. This must be a valid alert type. */
+        fun type(type: JsonField<Type>) = apply { body.type(type) }
+
         /** The metric to track usage for. */
         fun metricId(metricId: String?) = apply { body.metricId(metricId) }
 
         /** The metric to track usage for. */
         fun metricId(metricId: Optional<String>) = metricId(metricId.orElse(null))
 
+        /** The metric to track usage for. */
+        fun metricId(metricId: JsonField<String>) = apply { body.metricId(metricId) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -312,25 +409,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): AlertCreateForSubscriptionParams =
             AlertCreateForSubscriptionParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
@@ -345,7 +423,9 @@ constructor(
     class Threshold
     @JsonCreator
     private constructor(
-        @JsonProperty("value") private val value: Double,
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<Double> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -355,12 +435,28 @@ constructor(
          * or below this value. For usage and cost alerts, the alert will fire at or above this
          * value.
          */
-        @JsonProperty("value") fun value(): Double = value
+        fun value(): Double = value.getRequired("value")
+
+        /**
+         * The value at which an alert will fire. For credit balance alerts, the alert will fire at
+         * or below this value. For usage and cost alerts, the alert will fire at or above this
+         * value.
+         */
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<Double> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Threshold = apply {
+            if (!validated) {
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -370,7 +466,7 @@ constructor(
 
         class Builder {
 
-            private var value: Double? = null
+            private var value: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -384,7 +480,14 @@ constructor(
              * at or below this value. For usage and cost alerts, the alert will fire at or above
              * this value.
              */
-            fun value(value: Double) = apply { this.value = value }
+            fun value(value: Double) = value(JsonField.of(value))
+
+            /**
+             * The value at which an alert will fire. For credit balance alerts, the alert will fire
+             * at or below this value. For usage and cost alerts, the alert will fire at or above
+             * this value.
+             */
+            fun value(value: JsonField<Double>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertDisableParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertDisableParams.kt
index bbe95c43..80085dd8 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertDisableParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertDisableParams.kt
@@ -10,6 +10,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to disable an alert. To disable a plan-level alert for a specific
+ * subscription, you must include the `subscription_id`. The `subscription_id` is not required for
+ * customer or subscription level alerts.
+ */
 class AlertDisableParams
 constructor(
     private val alertConfigurationId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertEnableParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertEnableParams.kt
index 2a91ab5b..fa7e1205 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertEnableParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertEnableParams.kt
@@ -10,6 +10,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to enable an alert. To enable a plan-level alert for a specific
+ * subscription, you must include the `subscription_id`. The `subscription_id` is not required for
+ * customer or subscription level alerts.
+ */
 class AlertEnableParams
 constructor(
     private val alertConfigurationId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertListParams.kt
index 19de6751..2d10e511 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertListParams.kt
@@ -10,6 +10,17 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of alerts within Orb.
+ *
+ * The request must specify one of `customer_id`, `external_customer_id`, or `subscription_id`.
+ *
+ * If querying by subscripion_id, the endpoint will return the subscription level alerts as well as
+ * the plan level alerts associated with the subscription.
+ *
+ * The list of alerts is ordered starting from the most recently created alert. This endpoint
+ * follows Orb's [standardized pagination format](../reference/pagination).
+ */
 class AlertListParams
 constructor(
     private val createdAtGt: OffsetDateTime?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertRetrieveParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertRetrieveParams.kt
index 24bbd18a..f81abfaf 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertRetrieveParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertRetrieveParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** This endpoint retrieves an alert by its ID. */
 class AlertRetrieveParams
 constructor(
     private val alertId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertUpdateParams.kt
index 4ae8de06..cf14aeed 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AlertUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -15,6 +17,7 @@ import com.withorb.api.core.immutableEmptyMap
 import com.withorb.api.core.toImmutable
 import java.util.Objects
 
+/** This endpoint updates the thresholds of an alert. */
 class AlertUpdateParams
 constructor(
     private val alertConfigurationId: String,
@@ -28,12 +31,15 @@ constructor(
     /** The thresholds that define the values at which the alert will be triggered. */
     fun thresholds(): List<Threshold> = body.thresholds()
 
+    /** The thresholds that define the values at which the alert will be triggered. */
+    fun _thresholds(): JsonField<List<Threshold>> = body._thresholds()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): AlertUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -51,18 +57,34 @@ constructor(
     class AlertUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("thresholds") private val thresholds: List<Threshold>,
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        private val thresholds: JsonField<List<Threshold>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The thresholds that define the values at which the alert will be triggered. */
-        @JsonProperty("thresholds") fun thresholds(): List<Threshold> = thresholds
+        fun thresholds(): List<Threshold> = thresholds.getRequired("thresholds")
+
+        /** The thresholds that define the values at which the alert will be triggered. */
+        @JsonProperty("thresholds")
+        @ExcludeMissing
+        fun _thresholds(): JsonField<List<Threshold>> = thresholds
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AlertUpdateBody = apply {
+            if (!validated) {
+                thresholds().forEach { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -72,23 +94,35 @@ constructor(
 
         class Builder {
 
-            private var thresholds: MutableList<Threshold>? = null
+            private var thresholds: JsonField<MutableList<Threshold>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(alertUpdateBody: AlertUpdateBody) = apply {
-                thresholds = alertUpdateBody.thresholds.toMutableList()
+                thresholds = alertUpdateBody.thresholds.map { it.toMutableList() }
                 additionalProperties = alertUpdateBody.additionalProperties.toMutableMap()
             }
 
             /** The thresholds that define the values at which the alert will be triggered. */
-            fun thresholds(thresholds: List<Threshold>) = apply {
-                this.thresholds = thresholds.toMutableList()
+            fun thresholds(thresholds: List<Threshold>) = thresholds(JsonField.of(thresholds))
+
+            /** The thresholds that define the values at which the alert will be triggered. */
+            fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+                this.thresholds = thresholds.map { it.toMutableList() }
             }
 
             /** The thresholds that define the values at which the alert will be triggered. */
             fun addThreshold(threshold: Threshold) = apply {
-                thresholds = (thresholds ?: mutableListOf()).apply { add(threshold) }
+                thresholds =
+                    (thresholds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(threshold)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -113,7 +147,7 @@ constructor(
             fun build(): AlertUpdateBody =
                 AlertUpdateBody(
                     checkNotNull(thresholds) { "`thresholds` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable()
                 )
         }
@@ -166,9 +200,33 @@ constructor(
         /** The thresholds that define the values at which the alert will be triggered. */
         fun thresholds(thresholds: List<Threshold>) = apply { body.thresholds(thresholds) }
 
+        /** The thresholds that define the values at which the alert will be triggered. */
+        fun thresholds(thresholds: JsonField<List<Threshold>>) = apply {
+            body.thresholds(thresholds)
+        }
+
         /** The thresholds that define the values at which the alert will be triggered. */
         fun addThreshold(threshold: Threshold) = apply { body.addThreshold(threshold) }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -267,25 +325,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): AlertUpdateParams =
             AlertUpdateParams(
                 checkNotNull(alertConfigurationId) {
@@ -302,7 +341,9 @@ constructor(
     class Threshold
     @JsonCreator
     private constructor(
-        @JsonProperty("value") private val value: Double,
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<Double> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -312,12 +353,28 @@ constructor(
          * or below this value. For usage and cost alerts, the alert will fire at or above this
          * value.
          */
-        @JsonProperty("value") fun value(): Double = value
+        fun value(): Double = value.getRequired("value")
+
+        /**
+         * The value at which an alert will fire. For credit balance alerts, the alert will fire at
+         * or below this value. For usage and cost alerts, the alert will fire at or above this
+         * value.
+         */
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<Double> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Threshold = apply {
+            if (!validated) {
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -327,7 +384,7 @@ constructor(
 
         class Builder {
 
-            private var value: Double? = null
+            private var value: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -341,7 +398,14 @@ constructor(
              * at or below this value. For usage and cost alerts, the alert will fire at or above
              * this value.
              */
-            fun value(value: Double) = apply { this.value = value }
+            fun value(value: Double) = value(JsonField.of(value))
+
+            /**
+             * The value at which an alert will fire. For credit balance alerts, the alert will fire
+             * at or below this value. For usage and cost alerts, the alert will fire at or above
+             * this value.
+             */
+            fun value(value: JsonField<Double>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/AmountDiscount.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/AmountDiscount.kt
index 742a810c..4aff865f 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/AmountDiscount.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/AmountDiscount.kt
@@ -51,7 +51,9 @@ private constructor(
     fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
     /** Only available if discount_type is `amount`. */
-    @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+    @JsonProperty("amount_discount")
+    @ExcludeMissing
+    fun _amountDiscount(): JsonField<String> = amountDiscount
 
     /**
      * List of price_ids that this discount applies to. For plan/plan phase discounts, this can be a
@@ -59,11 +61,13 @@ private constructor(
      */
     @JsonProperty("applies_to_price_ids")
     @ExcludeMissing
-    fun _appliesToPriceIds() = appliesToPriceIds
+    fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-    @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+    @JsonProperty("discount_type")
+    @ExcludeMissing
+    fun _discountType(): JsonField<DiscountType> = discountType
 
-    @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+    @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -90,16 +94,16 @@ private constructor(
 
     class Builder {
 
-        private var amountDiscount: JsonField<String> = JsonMissing.of()
-        private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-        private var discountType: JsonField<DiscountType> = JsonMissing.of()
+        private var amountDiscount: JsonField<String>? = null
+        private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+        private var discountType: JsonField<DiscountType>? = null
         private var reason: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(amountDiscount: AmountDiscount) = apply {
             this.amountDiscount = amountDiscount.amountDiscount
-            appliesToPriceIds = amountDiscount.appliesToPriceIds
+            appliesToPriceIds = amountDiscount.appliesToPriceIds.map { it.toMutableList() }
             discountType = amountDiscount.discountType
             reason = amountDiscount.reason
             additionalProperties = amountDiscount.additionalProperties.toMutableMap()
@@ -125,7 +129,24 @@ private constructor(
          * be a subset of prices.
          */
         fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-            this.appliesToPriceIds = appliesToPriceIds
+            this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+        }
+
+        /**
+         * List of price_ids that this discount applies to. For plan/plan phase discounts, this can
+         * be a subset of prices.
+         */
+        fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+            appliesToPriceIds =
+                (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(appliesToPriceId)
+                }
         }
 
         fun discountType(discountType: DiscountType) = discountType(JsonField.of(discountType))
@@ -134,7 +155,9 @@ private constructor(
             this.discountType = discountType
         }
 
-        fun reason(reason: String) = reason(JsonField.of(reason))
+        fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+        fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
         fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -159,9 +182,12 @@ private constructor(
 
         fun build(): AmountDiscount =
             AmountDiscount(
-                amountDiscount,
-                appliesToPriceIds.map { it.toImmutable() },
-                discountType,
+                checkNotNull(amountDiscount) { "`amountDiscount` is required but was not set" },
+                checkNotNull(appliesToPriceIds) {
+                        "`appliesToPriceIds` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(discountType) { "`discountType` is required but was not set" },
                 reason,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/BillableMetric.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/BillableMetric.kt
index 78faf058..9cadf9c3 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/BillableMetric.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/BillableMetric.kt
@@ -64,27 +64,27 @@ private constructor(
 
     fun status(): Status = status.getRequired("status")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("description") @ExcludeMissing fun _description() = description
+    @JsonProperty("description") @ExcludeMissing fun _description(): JsonField<String> = description
 
     /**
      * The Item resource represents a sellable product or good. Items are associated with all line
      * items, billable metrics, and prices and are used for defining external sync behavior for
      * invoices and tax calculation purposes.
      */
-    @JsonProperty("item") @ExcludeMissing fun _item() = item
+    @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -113,12 +113,12 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var description: JsonField<String> = JsonMissing.of()
-        private var item: JsonField<Item> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var description: JsonField<String>? = null
+        private var item: JsonField<Item>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var name: JsonField<String>? = null
+        private var status: JsonField<Status>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -136,7 +136,9 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
-        fun description(description: String) = description(JsonField.of(description))
+        fun description(description: String?) = description(JsonField.ofNullable(description))
+
+        fun description(description: Optional<String>) = description(description.orElse(null))
 
         fun description(description: JsonField<String>) = apply { this.description = description }
 
@@ -197,12 +199,12 @@ private constructor(
 
         fun build(): BillableMetric =
             BillableMetric(
-                id,
-                description,
-                item,
-                metadata,
-                name,
-                status,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(description) { "`description` is required but was not set" },
+                checkNotNull(item) { "`item` is required but was not set" },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(name) { "`name` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Coupon.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Coupon.kt
index 0dc97ab6..3ef0e60a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Coupon.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Coupon.kt
@@ -125,33 +125,43 @@ private constructor(
     fun timesRedeemed(): Long = timesRedeemed.getRequired("times_redeemed")
 
     /** Also referred to as coupon_id in this documentation. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * An archived coupon can no longer be redeemed. Active coupons will have a value of null for
      * `archived_at`; this field will be non-null for archived coupons.
      */
-    @JsonProperty("archived_at") @ExcludeMissing fun _archivedAt() = archivedAt
+    @JsonProperty("archived_at")
+    @ExcludeMissing
+    fun _archivedAt(): JsonField<OffsetDateTime> = archivedAt
 
-    @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+    @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
     /**
      * This allows for a coupon's discount to apply for a limited time (determined in months); a
      * `null` value here means "unlimited time".
      */
-    @JsonProperty("duration_in_months") @ExcludeMissing fun _durationInMonths() = durationInMonths
+    @JsonProperty("duration_in_months")
+    @ExcludeMissing
+    fun _durationInMonths(): JsonField<Long> = durationInMonths
 
     /**
      * The maximum number of redemptions allowed for this coupon before it is exhausted; `null` here
      * means "unlimited".
      */
-    @JsonProperty("max_redemptions") @ExcludeMissing fun _maxRedemptions() = maxRedemptions
+    @JsonProperty("max_redemptions")
+    @ExcludeMissing
+    fun _maxRedemptions(): JsonField<Long> = maxRedemptions
 
     /** This string can be used to redeem this coupon for a given subscription. */
-    @JsonProperty("redemption_code") @ExcludeMissing fun _redemptionCode() = redemptionCode
+    @JsonProperty("redemption_code")
+    @ExcludeMissing
+    fun _redemptionCode(): JsonField<String> = redemptionCode
 
     /** The number of times this coupon has been redeemed. */
-    @JsonProperty("times_redeemed") @ExcludeMissing fun _timesRedeemed() = timesRedeemed
+    @JsonProperty("times_redeemed")
+    @ExcludeMissing
+    fun _timesRedeemed(): JsonField<Long> = timesRedeemed
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -181,13 +191,13 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var archivedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var discount: JsonField<Discount> = JsonMissing.of()
-        private var durationInMonths: JsonField<Long> = JsonMissing.of()
-        private var maxRedemptions: JsonField<Long> = JsonMissing.of()
-        private var redemptionCode: JsonField<String> = JsonMissing.of()
-        private var timesRedeemed: JsonField<Long> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var archivedAt: JsonField<OffsetDateTime>? = null
+        private var discount: JsonField<Discount>? = null
+        private var durationInMonths: JsonField<Long>? = null
+        private var maxRedemptions: JsonField<Long>? = null
+        private var redemptionCode: JsonField<String>? = null
+        private var timesRedeemed: JsonField<Long>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -212,7 +222,13 @@ private constructor(
          * An archived coupon can no longer be redeemed. Active coupons will have a value of null
          * for `archived_at`; this field will be non-null for archived coupons.
          */
-        fun archivedAt(archivedAt: OffsetDateTime) = archivedAt(JsonField.of(archivedAt))
+        fun archivedAt(archivedAt: OffsetDateTime?) = archivedAt(JsonField.ofNullable(archivedAt))
+
+        /**
+         * An archived coupon can no longer be redeemed. Active coupons will have a value of null
+         * for `archived_at`; this field will be non-null for archived coupons.
+         */
+        fun archivedAt(archivedAt: Optional<OffsetDateTime>) = archivedAt(archivedAt.orElse(null))
 
         /**
          * An archived coupon can no longer be redeemed. Active coupons will have a value of null
@@ -226,12 +242,32 @@ private constructor(
 
         fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+        fun discount(percentageDiscount: PercentageDiscount) =
+            discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+        fun discount(amountDiscount: AmountDiscount) =
+            discount(Discount.ofAmountDiscount(amountDiscount))
+
         /**
          * This allows for a coupon's discount to apply for a limited time (determined in months); a
          * `null` value here means "unlimited time".
          */
-        fun durationInMonths(durationInMonths: Long) =
-            durationInMonths(JsonField.of(durationInMonths))
+        fun durationInMonths(durationInMonths: Long?) =
+            durationInMonths(JsonField.ofNullable(durationInMonths))
+
+        /**
+         * This allows for a coupon's discount to apply for a limited time (determined in months); a
+         * `null` value here means "unlimited time".
+         */
+        fun durationInMonths(durationInMonths: Long) = durationInMonths(durationInMonths as Long?)
+
+        /**
+         * This allows for a coupon's discount to apply for a limited time (determined in months); a
+         * `null` value here means "unlimited time".
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun durationInMonths(durationInMonths: Optional<Long>) =
+            durationInMonths(durationInMonths.orElse(null) as Long?)
 
         /**
          * This allows for a coupon's discount to apply for a limited time (determined in months); a
@@ -245,7 +281,22 @@ private constructor(
          * The maximum number of redemptions allowed for this coupon before it is exhausted; `null`
          * here means "unlimited".
          */
-        fun maxRedemptions(maxRedemptions: Long) = maxRedemptions(JsonField.of(maxRedemptions))
+        fun maxRedemptions(maxRedemptions: Long?) =
+            maxRedemptions(JsonField.ofNullable(maxRedemptions))
+
+        /**
+         * The maximum number of redemptions allowed for this coupon before it is exhausted; `null`
+         * here means "unlimited".
+         */
+        fun maxRedemptions(maxRedemptions: Long) = maxRedemptions(maxRedemptions as Long?)
+
+        /**
+         * The maximum number of redemptions allowed for this coupon before it is exhausted; `null`
+         * here means "unlimited".
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun maxRedemptions(maxRedemptions: Optional<Long>) =
+            maxRedemptions(maxRedemptions.orElse(null) as Long?)
 
         /**
          * The maximum number of redemptions allowed for this coupon before it is exhausted; `null`
@@ -292,13 +343,13 @@ private constructor(
 
         fun build(): Coupon =
             Coupon(
-                id,
-                archivedAt,
-                discount,
-                durationInMonths,
-                maxRedemptions,
-                redemptionCode,
-                timesRedeemed,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(archivedAt) { "`archivedAt` is required but was not set" },
+                checkNotNull(discount) { "`discount` is required but was not set" },
+                checkNotNull(durationInMonths) { "`durationInMonths` is required but was not set" },
+                checkNotNull(maxRedemptions) { "`maxRedemptions` is required but was not set" },
+                checkNotNull(redemptionCode) { "`redemptionCode` is required but was not set" },
+                checkNotNull(timesRedeemed) { "`timesRedeemed` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponArchiveParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponArchiveParams.kt
index 02209378..890b6957 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponArchiveParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponArchiveParams.kt
@@ -10,6 +10,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows a coupon to be archived. Archived coupons can no longer be redeemed, and
+ * will be hidden from lists of active coupons. Additionally, once a coupon is archived, its
+ * redemption code can be reused for a different coupon.
+ */
 class CouponArchiveParams
 constructor(
     private val couponId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponCreateParams.kt
index e3b39047..cb4aa833 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponCreateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,10 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint allows the creation of coupons, which can then be redeemed at subscription creation
+ * or plan change.
+ */
 class CouponCreateParams
 constructor(
     private val body: CouponCreateBody,
@@ -54,12 +59,29 @@ constructor(
      */
     fun maxRedemptions(): Optional<Long> = body.maxRedemptions()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _discount(): JsonField<Discount> = body._discount()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** This string can be used to redeem this coupon for a given subscription. */
+    fun _redemptionCode(): JsonField<String> = body._redemptionCode()
+
+    /**
+     * This allows for a coupon's discount to apply for a limited time (determined in months); a
+     * `null` value here means "unlimited time".
+     */
+    fun _durationInMonths(): JsonField<Long> = body._durationInMonths()
+
+    /**
+     * The maximum number of redemptions allowed for this coupon before it is exhausted;`null` here
+     * means "unlimited".
+     */
+    fun _maxRedemptions(): JsonField<Long> = body._maxRedemptions()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CouponCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -70,37 +92,80 @@ constructor(
     class CouponCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("discount") private val discount: Discount,
-        @JsonProperty("redemption_code") private val redemptionCode: String,
-        @JsonProperty("duration_in_months") private val durationInMonths: Long?,
-        @JsonProperty("max_redemptions") private val maxRedemptions: Long?,
+        @JsonProperty("discount")
+        @ExcludeMissing
+        private val discount: JsonField<Discount> = JsonMissing.of(),
+        @JsonProperty("redemption_code")
+        @ExcludeMissing
+        private val redemptionCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("duration_in_months")
+        @ExcludeMissing
+        private val durationInMonths: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("max_redemptions")
+        @ExcludeMissing
+        private val maxRedemptions: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("discount") fun discount(): Discount = discount
+        fun discount(): Discount = discount.getRequired("discount")
 
         /** This string can be used to redeem this coupon for a given subscription. */
-        @JsonProperty("redemption_code") fun redemptionCode(): String = redemptionCode
+        fun redemptionCode(): String = redemptionCode.getRequired("redemption_code")
+
+        /**
+         * This allows for a coupon's discount to apply for a limited time (determined in months); a
+         * `null` value here means "unlimited time".
+         */
+        fun durationInMonths(): Optional<Long> =
+            Optional.ofNullable(durationInMonths.getNullable("duration_in_months"))
+
+        /**
+         * The maximum number of redemptions allowed for this coupon before it is exhausted;`null`
+         * here means "unlimited".
+         */
+        fun maxRedemptions(): Optional<Long> =
+            Optional.ofNullable(maxRedemptions.getNullable("max_redemptions"))
+
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
+
+        /** This string can be used to redeem this coupon for a given subscription. */
+        @JsonProperty("redemption_code")
+        @ExcludeMissing
+        fun _redemptionCode(): JsonField<String> = redemptionCode
 
         /**
          * This allows for a coupon's discount to apply for a limited time (determined in months); a
          * `null` value here means "unlimited time".
          */
         @JsonProperty("duration_in_months")
-        fun durationInMonths(): Optional<Long> = Optional.ofNullable(durationInMonths)
+        @ExcludeMissing
+        fun _durationInMonths(): JsonField<Long> = durationInMonths
 
         /**
          * The maximum number of redemptions allowed for this coupon before it is exhausted;`null`
          * here means "unlimited".
          */
         @JsonProperty("max_redemptions")
-        fun maxRedemptions(): Optional<Long> = Optional.ofNullable(maxRedemptions)
+        @ExcludeMissing
+        fun _maxRedemptions(): JsonField<Long> = maxRedemptions
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CouponCreateBody = apply {
+            if (!validated) {
+                discount()
+                redemptionCode()
+                durationInMonths()
+                maxRedemptions()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -110,10 +175,10 @@ constructor(
 
         class Builder {
 
-            private var discount: Discount? = null
-            private var redemptionCode: String? = null
-            private var durationInMonths: Long? = null
-            private var maxRedemptions: Long? = null
+            private var discount: JsonField<Discount>? = null
+            private var redemptionCode: JsonField<String>? = null
+            private var durationInMonths: JsonField<Long> = JsonMissing.of()
+            private var maxRedemptions: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -125,20 +190,22 @@ constructor(
                 additionalProperties = couponCreateBody.additionalProperties.toMutableMap()
             }
 
-            fun discount(discount: Discount) = apply { this.discount = discount }
+            fun discount(discount: Discount) = discount(JsonField.of(discount))
+
+            fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
             fun discount(newCouponPercentageDiscount: Discount.NewCouponPercentageDiscount) =
-                apply {
-                    this.discount =
-                        Discount.ofNewCouponPercentageDiscount(newCouponPercentageDiscount)
-                }
+                discount(Discount.ofNewCouponPercentageDiscount(newCouponPercentageDiscount))
 
-            fun discount(newCouponAmountDiscount: Discount.NewCouponAmountDiscount) = apply {
-                this.discount = Discount.ofNewCouponAmountDiscount(newCouponAmountDiscount)
-            }
+            fun discount(newCouponAmountDiscount: Discount.NewCouponAmountDiscount) =
+                discount(Discount.ofNewCouponAmountDiscount(newCouponAmountDiscount))
+
+            /** This string can be used to redeem this coupon for a given subscription. */
+            fun redemptionCode(redemptionCode: String) =
+                redemptionCode(JsonField.of(redemptionCode))
 
             /** This string can be used to redeem this coupon for a given subscription. */
-            fun redemptionCode(redemptionCode: String) = apply {
+            fun redemptionCode(redemptionCode: JsonField<String>) = apply {
                 this.redemptionCode = redemptionCode
             }
 
@@ -146,9 +213,8 @@ constructor(
              * This allows for a coupon's discount to apply for a limited time (determined in
              * months); a `null` value here means "unlimited time".
              */
-            fun durationInMonths(durationInMonths: Long?) = apply {
-                this.durationInMonths = durationInMonths
-            }
+            fun durationInMonths(durationInMonths: Long?) =
+                durationInMonths(JsonField.ofNullable(durationInMonths))
 
             /**
              * This allows for a coupon's discount to apply for a limited time (determined in
@@ -165,13 +231,20 @@ constructor(
             fun durationInMonths(durationInMonths: Optional<Long>) =
                 durationInMonths(durationInMonths.orElse(null) as Long?)
 
+            /**
+             * This allows for a coupon's discount to apply for a limited time (determined in
+             * months); a `null` value here means "unlimited time".
+             */
+            fun durationInMonths(durationInMonths: JsonField<Long>) = apply {
+                this.durationInMonths = durationInMonths
+            }
+
             /**
              * The maximum number of redemptions allowed for this coupon before it is
              * exhausted;`null` here means "unlimited".
              */
-            fun maxRedemptions(maxRedemptions: Long?) = apply {
-                this.maxRedemptions = maxRedemptions
-            }
+            fun maxRedemptions(maxRedemptions: Long?) =
+                maxRedemptions(JsonField.ofNullable(maxRedemptions))
 
             /**
              * The maximum number of redemptions allowed for this coupon before it is
@@ -187,6 +260,14 @@ constructor(
             fun maxRedemptions(maxRedemptions: Optional<Long>) =
                 maxRedemptions(maxRedemptions.orElse(null) as Long?)
 
+            /**
+             * The maximum number of redemptions allowed for this coupon before it is
+             * exhausted;`null` here means "unlimited".
+             */
+            fun maxRedemptions(maxRedemptions: JsonField<Long>) = apply {
+                this.maxRedemptions = maxRedemptions
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -257,6 +338,8 @@ constructor(
 
         fun discount(discount: Discount) = apply { body.discount(discount) }
 
+        fun discount(discount: JsonField<Discount>) = apply { body.discount(discount) }
+
         fun discount(newCouponPercentageDiscount: Discount.NewCouponPercentageDiscount) = apply {
             body.discount(newCouponPercentageDiscount)
         }
@@ -268,6 +351,11 @@ constructor(
         /** This string can be used to redeem this coupon for a given subscription. */
         fun redemptionCode(redemptionCode: String) = apply { body.redemptionCode(redemptionCode) }
 
+        /** This string can be used to redeem this coupon for a given subscription. */
+        fun redemptionCode(redemptionCode: JsonField<String>) = apply {
+            body.redemptionCode(redemptionCode)
+        }
+
         /**
          * This allows for a coupon's discount to apply for a limited time (determined in months); a
          * `null` value here means "unlimited time".
@@ -290,6 +378,14 @@ constructor(
         fun durationInMonths(durationInMonths: Optional<Long>) =
             durationInMonths(durationInMonths.orElse(null) as Long?)
 
+        /**
+         * This allows for a coupon's discount to apply for a limited time (determined in months); a
+         * `null` value here means "unlimited time".
+         */
+        fun durationInMonths(durationInMonths: JsonField<Long>) = apply {
+            body.durationInMonths(durationInMonths)
+        }
+
         /**
          * The maximum number of redemptions allowed for this coupon before it is exhausted;`null`
          * here means "unlimited".
@@ -310,6 +406,33 @@ constructor(
         fun maxRedemptions(maxRedemptions: Optional<Long>) =
             maxRedemptions(maxRedemptions.orElse(null) as Long?)
 
+        /**
+         * The maximum number of redemptions allowed for this coupon before it is exhausted;`null`
+         * here means "unlimited".
+         */
+        fun maxRedemptions(maxRedemptions: JsonField<Long>) = apply {
+            body.maxRedemptions(maxRedemptions)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -408,25 +531,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CouponCreateParams =
             CouponCreateParams(
                 body.build(),
@@ -444,6 +548,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun newCouponPercentageDiscount(): Optional<NewCouponPercentageDiscount> =
             Optional.ofNullable(newCouponPercentageDiscount)
 
@@ -472,6 +578,17 @@ constructor(
             }
         }
 
+        fun validate(): Discount = apply {
+            if (!validated) {
+                if (newCouponPercentageDiscount == null && newCouponAmountDiscount == null) {
+                    throw OrbInvalidDataException("Unknown Discount: $_json")
+                }
+                newCouponPercentageDiscount?.validate()
+                newCouponAmountDiscount?.validate()
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
@@ -526,14 +643,20 @@ constructor(
 
                 when (discountType) {
                     "percentage" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewCouponPercentageDiscount>())?.let {
-                            return Discount(newCouponPercentageDiscount = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewCouponPercentageDiscount>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Discount(newCouponPercentageDiscount = it, _json = json)
+                            }
                     }
                     "amount" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewCouponAmountDiscount>())?.let {
-                            return Discount(newCouponAmountDiscount = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewCouponAmountDiscount>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Discount(newCouponAmountDiscount = it, _json = json)
+                            }
                     }
                 }
 
@@ -563,21 +686,42 @@ constructor(
         class NewCouponPercentageDiscount
         @JsonCreator
         private constructor(
-            @JsonProperty("discount_type") private val discountType: DiscountType,
-            @JsonProperty("percentage_discount") private val percentageDiscount: Double,
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+            @JsonProperty("percentage_discount")
+            @ExcludeMissing
+            private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+            fun percentageDiscount(): Double = percentageDiscount.getRequired("percentage_discount")
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             @JsonProperty("percentage_discount")
-            fun percentageDiscount(): Double = percentageDiscount
+            @ExcludeMissing
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewCouponPercentageDiscount = apply {
+                if (!validated) {
+                    discountType()
+                    percentageDiscount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -587,8 +731,8 @@ constructor(
 
             class Builder {
 
-                private var discountType: DiscountType? = null
-                private var percentageDiscount: Double? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var percentageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -600,11 +744,17 @@ constructor(
                             newCouponPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
-                fun percentageDiscount(percentageDiscount: Double) = apply {
+                fun percentageDiscount(percentageDiscount: Double) =
+                    percentageDiscount(JsonField.of(percentageDiscount))
+
+                fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
                     this.percentageDiscount = percentageDiscount
                 }
 
@@ -713,20 +863,42 @@ constructor(
         class NewCouponAmountDiscount
         @JsonCreator
         private constructor(
-            @JsonProperty("amount_discount") private val amountDiscount: String,
-            @JsonProperty("discount_type") private val discountType: DiscountType,
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            private val amountDiscount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+            fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewCouponAmountDiscount = apply {
+                if (!validated) {
+                    amountDiscount()
+                    discountType()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -736,8 +908,8 @@ constructor(
 
             class Builder {
 
-                private var amountDiscount: String? = null
-                private var discountType: DiscountType? = null
+                private var amountDiscount: JsonField<String>? = null
+                private var discountType: JsonField<DiscountType>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -748,11 +920,17 @@ constructor(
                         newCouponAmountDiscount.additionalProperties.toMutableMap()
                 }
 
-                fun amountDiscount(amountDiscount: String) = apply {
+                fun amountDiscount(amountDiscount: String) =
+                    amountDiscount(JsonField.of(amountDiscount))
+
+                fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                     this.amountDiscount = amountDiscount
                 }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponFetchParams.kt
index 6dca4c54..e5c69f2d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponFetchParams.kt
@@ -7,6 +7,10 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint retrieves a coupon by its ID. To fetch coupons by their redemption code, use the
+ * [List coupons](list-coupons) endpoint with the redemption_code parameter.
+ */
 class CouponFetchParams
 constructor(
     private val couponId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponListParams.kt
index 14f5711e..4fc6ac77 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponListParams.kt
@@ -8,6 +8,13 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all coupons for an account in a list format.
+ *
+ * The list of coupons is ordered starting from the most recently created coupon. The response also
+ * includes `pagination_metadata`, which lets the caller retrieve the next page of results if they
+ * exist. More information about pagination can be found in the Pagination-metadata schema.
+ */
 class CouponListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponSubscriptionListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponSubscriptionListParams.kt
index c96c78be..b52424ad 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponSubscriptionListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CouponSubscriptionListParams.kt
@@ -8,6 +8,12 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all subscriptions that have redeemed a given coupon as a
+ * [paginated](../reference/pagination) list, ordered starting from the most recently created
+ * subscription. For a full discussion of the subscription resource, see
+ * [Subscription](../guides/concepts#subscription).
+ */
 class CouponSubscriptionListParams
 constructor(
     private val couponId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNote.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNote.kt
index 85aa4b0f..a6d6497e 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNote.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNote.kt
@@ -121,53 +121,63 @@ private constructor(
         Optional.ofNullable(discounts.getNullable("discounts"))
 
     /** The Orb id of this credit note. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The creation time of the resource in Orb. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /** The unique identifier for credit notes. */
-    @JsonProperty("credit_note_number") @ExcludeMissing fun _creditNoteNumber() = creditNoteNumber
+    @JsonProperty("credit_note_number")
+    @ExcludeMissing
+    fun _creditNoteNumber(): JsonField<String> = creditNoteNumber
 
     /** A URL to a PDF of the credit note. */
-    @JsonProperty("credit_note_pdf") @ExcludeMissing fun _creditNotePdf() = creditNotePdf
+    @JsonProperty("credit_note_pdf")
+    @ExcludeMissing
+    fun _creditNotePdf(): JsonField<String> = creditNotePdf
 
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /** The id of the invoice resource that this credit note is applied to. */
-    @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId() = invoiceId
+    @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
     /** All of the line items associated with this credit note. */
-    @JsonProperty("line_items") @ExcludeMissing fun _lineItems() = lineItems
+    @JsonProperty("line_items")
+    @ExcludeMissing
+    fun _lineItems(): JsonField<List<LineItem>> = lineItems
 
     /** The maximum amount applied on the original invoice */
     @JsonProperty("maximum_amount_adjustment")
     @ExcludeMissing
-    fun _maximumAmountAdjustment() = maximumAmountAdjustment
+    fun _maximumAmountAdjustment(): JsonField<MaximumAmountAdjustment> = maximumAmountAdjustment
 
     /** An optional memo supplied on the credit note. */
-    @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+    @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
     /** Any credited amount from the applied minimum on the invoice. */
     @JsonProperty("minimum_amount_refunded")
     @ExcludeMissing
-    fun _minimumAmountRefunded() = minimumAmountRefunded
+    fun _minimumAmountRefunded(): JsonField<String> = minimumAmountRefunded
 
-    @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+    @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<Reason> = reason
 
     /** The total prior to any creditable invoice-level discounts or minimums. */
-    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
     /** The total including creditable invoice-level discounts or minimums, and tax. */
-    @JsonProperty("total") @ExcludeMissing fun _total() = total
+    @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
-    @JsonProperty("type") @ExcludeMissing fun _type() = type
+    @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
     /** The time at which the credit note was voided in Orb, if applicable. */
-    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt() = voidedAt
+    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt(): JsonField<OffsetDateTime> = voidedAt
 
     /** Any discounts applied on the original invoice. */
-    @JsonProperty("discounts") @ExcludeMissing fun _discounts() = discounts
+    @JsonProperty("discounts")
+    @ExcludeMissing
+    fun _discounts(): JsonField<List<Discount>> = discounts
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -206,22 +216,22 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var creditNoteNumber: JsonField<String> = JsonMissing.of()
-        private var creditNotePdf: JsonField<String> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var invoiceId: JsonField<String> = JsonMissing.of()
-        private var lineItems: JsonField<List<LineItem>> = JsonMissing.of()
-        private var maximumAmountAdjustment: JsonField<MaximumAmountAdjustment> = JsonMissing.of()
-        private var memo: JsonField<String> = JsonMissing.of()
-        private var minimumAmountRefunded: JsonField<String> = JsonMissing.of()
-        private var reason: JsonField<Reason> = JsonMissing.of()
-        private var subtotal: JsonField<String> = JsonMissing.of()
-        private var total: JsonField<String> = JsonMissing.of()
-        private var type: JsonField<Type> = JsonMissing.of()
-        private var voidedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var discounts: JsonField<List<Discount>> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var creditNoteNumber: JsonField<String>? = null
+        private var creditNotePdf: JsonField<String>? = null
+        private var customer: JsonField<Customer>? = null
+        private var invoiceId: JsonField<String>? = null
+        private var lineItems: JsonField<MutableList<LineItem>>? = null
+        private var maximumAmountAdjustment: JsonField<MaximumAmountAdjustment>? = null
+        private var memo: JsonField<String>? = null
+        private var minimumAmountRefunded: JsonField<String>? = null
+        private var reason: JsonField<Reason>? = null
+        private var subtotal: JsonField<String>? = null
+        private var total: JsonField<String>? = null
+        private var type: JsonField<Type>? = null
+        private var voidedAt: JsonField<OffsetDateTime>? = null
+        private var discounts: JsonField<MutableList<Discount>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -232,7 +242,7 @@ private constructor(
             creditNotePdf = creditNote.creditNotePdf
             customer = creditNote.customer
             invoiceId = creditNote.invoiceId
-            lineItems = creditNote.lineItems
+            lineItems = creditNote.lineItems.map { it.toMutableList() }
             maximumAmountAdjustment = creditNote.maximumAmountAdjustment
             memo = creditNote.memo
             minimumAmountRefunded = creditNote.minimumAmountRefunded
@@ -241,7 +251,7 @@ private constructor(
             total = creditNote.total
             type = creditNote.type
             voidedAt = creditNote.voidedAt
-            discounts = creditNote.discounts
+            discounts = creditNote.discounts.map { it.toMutableList() }
             additionalProperties = creditNote.additionalProperties.toMutableMap()
         }
 
@@ -267,7 +277,12 @@ private constructor(
         }
 
         /** A URL to a PDF of the credit note. */
-        fun creditNotePdf(creditNotePdf: String) = creditNotePdf(JsonField.of(creditNotePdf))
+        fun creditNotePdf(creditNotePdf: String?) =
+            creditNotePdf(JsonField.ofNullable(creditNotePdf))
+
+        /** A URL to a PDF of the credit note. */
+        fun creditNotePdf(creditNotePdf: Optional<String>) =
+            creditNotePdf(creditNotePdf.orElse(null))
 
         /** A URL to a PDF of the credit note. */
         fun creditNotePdf(creditNotePdf: JsonField<String>) = apply {
@@ -288,11 +303,31 @@ private constructor(
         fun lineItems(lineItems: List<LineItem>) = lineItems(JsonField.of(lineItems))
 
         /** All of the line items associated with this credit note. */
-        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply { this.lineItems = lineItems }
+        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply {
+            this.lineItems = lineItems.map { it.toMutableList() }
+        }
+
+        /** All of the line items associated with this credit note. */
+        fun addLineItem(lineItem: LineItem) = apply {
+            lineItems =
+                (lineItems ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(lineItem)
+                }
+        }
 
         /** The maximum amount applied on the original invoice */
-        fun maximumAmountAdjustment(maximumAmountAdjustment: MaximumAmountAdjustment) =
-            maximumAmountAdjustment(JsonField.of(maximumAmountAdjustment))
+        fun maximumAmountAdjustment(maximumAmountAdjustment: MaximumAmountAdjustment?) =
+            maximumAmountAdjustment(JsonField.ofNullable(maximumAmountAdjustment))
+
+        /** The maximum amount applied on the original invoice */
+        fun maximumAmountAdjustment(maximumAmountAdjustment: Optional<MaximumAmountAdjustment>) =
+            maximumAmountAdjustment(maximumAmountAdjustment.orElse(null))
 
         /** The maximum amount applied on the original invoice */
         fun maximumAmountAdjustment(maximumAmountAdjustment: JsonField<MaximumAmountAdjustment>) =
@@ -301,21 +336,30 @@ private constructor(
             }
 
         /** An optional memo supplied on the credit note. */
-        fun memo(memo: String) = memo(JsonField.of(memo))
+        fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+        /** An optional memo supplied on the credit note. */
+        fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
         /** An optional memo supplied on the credit note. */
         fun memo(memo: JsonField<String>) = apply { this.memo = memo }
 
         /** Any credited amount from the applied minimum on the invoice. */
-        fun minimumAmountRefunded(minimumAmountRefunded: String) =
-            minimumAmountRefunded(JsonField.of(minimumAmountRefunded))
+        fun minimumAmountRefunded(minimumAmountRefunded: String?) =
+            minimumAmountRefunded(JsonField.ofNullable(minimumAmountRefunded))
+
+        /** Any credited amount from the applied minimum on the invoice. */
+        fun minimumAmountRefunded(minimumAmountRefunded: Optional<String>) =
+            minimumAmountRefunded(minimumAmountRefunded.orElse(null))
 
         /** Any credited amount from the applied minimum on the invoice. */
         fun minimumAmountRefunded(minimumAmountRefunded: JsonField<String>) = apply {
             this.minimumAmountRefunded = minimumAmountRefunded
         }
 
-        fun reason(reason: Reason) = reason(JsonField.of(reason))
+        fun reason(reason: Reason?) = reason(JsonField.ofNullable(reason))
+
+        fun reason(reason: Optional<Reason>) = reason(reason.orElse(null))
 
         fun reason(reason: JsonField<Reason>) = apply { this.reason = reason }
 
@@ -336,7 +380,10 @@ private constructor(
         fun type(type: JsonField<Type>) = apply { this.type = type }
 
         /** The time at which the credit note was voided in Orb, if applicable. */
-        fun voidedAt(voidedAt: OffsetDateTime) = voidedAt(JsonField.of(voidedAt))
+        fun voidedAt(voidedAt: OffsetDateTime?) = voidedAt(JsonField.ofNullable(voidedAt))
+
+        /** The time at which the credit note was voided in Orb, if applicable. */
+        fun voidedAt(voidedAt: Optional<OffsetDateTime>) = voidedAt(voidedAt.orElse(null))
 
         /** The time at which the credit note was voided in Orb, if applicable. */
         fun voidedAt(voidedAt: JsonField<OffsetDateTime>) = apply { this.voidedAt = voidedAt }
@@ -345,7 +392,23 @@ private constructor(
         fun discounts(discounts: List<Discount>) = discounts(JsonField.of(discounts))
 
         /** Any discounts applied on the original invoice. */
-        fun discounts(discounts: JsonField<List<Discount>>) = apply { this.discounts = discounts }
+        fun discounts(discounts: JsonField<List<Discount>>) = apply {
+            this.discounts = discounts.map { it.toMutableList() }
+        }
+
+        /** Any discounts applied on the original invoice. */
+        fun addDiscount(discount: Discount) = apply {
+            discounts =
+                (discounts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discount)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -368,22 +431,27 @@ private constructor(
 
         fun build(): CreditNote =
             CreditNote(
-                id,
-                createdAt,
-                creditNoteNumber,
-                creditNotePdf,
-                customer,
-                invoiceId,
-                lineItems.map { it.toImmutable() },
-                maximumAmountAdjustment,
-                memo,
-                minimumAmountRefunded,
-                reason,
-                subtotal,
-                total,
-                type,
-                voidedAt,
-                discounts.map { it.toImmutable() },
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(creditNoteNumber) { "`creditNoteNumber` is required but was not set" },
+                checkNotNull(creditNotePdf) { "`creditNotePdf` is required but was not set" },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(invoiceId) { "`invoiceId` is required but was not set" },
+                checkNotNull(lineItems) { "`lineItems` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(maximumAmountAdjustment) {
+                    "`maximumAmountAdjustment` is required but was not set"
+                },
+                checkNotNull(memo) { "`memo` is required but was not set" },
+                checkNotNull(minimumAmountRefunded) {
+                    "`minimumAmountRefunded` is required but was not set"
+                },
+                checkNotNull(reason) { "`reason` is required but was not set" },
+                checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                checkNotNull(total) { "`total` is required but was not set" },
+                checkNotNull(type) { "`type` is required but was not set" },
+                checkNotNull(voidedAt) { "`voidedAt` is required but was not set" },
+                (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                 additionalProperties.toImmutable(),
             )
     }
@@ -405,11 +473,11 @@ private constructor(
         fun externalCustomerId(): Optional<String> =
             Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("external_customer_id")
         @ExcludeMissing
-        fun _externalCustomerId() = externalCustomerId
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -434,8 +502,8 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalCustomerId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -449,8 +517,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun externalCustomerId(externalCustomerId: String) =
-                externalCustomerId(JsonField.of(externalCustomerId))
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+            fun externalCustomerId(externalCustomerId: Optional<String>) =
+                externalCustomerId(externalCustomerId.orElse(null))
 
             fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                 this.externalCustomerId = externalCustomerId
@@ -477,8 +548,10 @@ private constructor(
 
             fun build(): Customer =
                 Customer(
-                    id,
-                    externalCustomerId,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalCustomerId) {
+                        "`externalCustomerId` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -551,25 +624,29 @@ private constructor(
             Optional.ofNullable(discounts.getNullable("discounts"))
 
         /** The Orb id of this resource. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The amount of the line item, including any line item minimums and discounts. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The name of the corresponding invoice line item. */
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** An optional quantity credited. */
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
         /** The amount of the line item, excluding any line item minimums and discounts. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
         /** Any tax amounts applied onto the line item. */
-        @JsonProperty("tax_amounts") @ExcludeMissing fun _taxAmounts() = taxAmounts
+        @JsonProperty("tax_amounts")
+        @ExcludeMissing
+        fun _taxAmounts(): JsonField<List<TaxAmount>> = taxAmounts
 
         /** Any line item discounts from the invoice's line item. */
-        @JsonProperty("discounts") @ExcludeMissing fun _discounts() = discounts
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -599,13 +676,13 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var taxAmounts: JsonField<List<TaxAmount>> = JsonMissing.of()
-            private var discounts: JsonField<List<Discount>> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var subtotal: JsonField<String>? = null
+            private var taxAmounts: JsonField<MutableList<TaxAmount>>? = null
+            private var discounts: JsonField<MutableList<Discount>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -615,8 +692,8 @@ private constructor(
                 name = lineItem.name
                 quantity = lineItem.quantity
                 subtotal = lineItem.subtotal
-                taxAmounts = lineItem.taxAmounts
-                discounts = lineItem.discounts
+                taxAmounts = lineItem.taxAmounts.map { it.toMutableList() }
+                discounts = lineItem.discounts.map { it.toMutableList() }
                 additionalProperties = lineItem.additionalProperties.toMutableMap()
             }
 
@@ -639,7 +716,14 @@ private constructor(
             fun name(name: JsonField<String>) = apply { this.name = name }
 
             /** An optional quantity credited. */
-            fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
+            fun quantity(quantity: Double?) = quantity(JsonField.ofNullable(quantity))
+
+            /** An optional quantity credited. */
+            fun quantity(quantity: Double) = quantity(quantity as Double?)
+
+            /** An optional quantity credited. */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun quantity(quantity: Optional<Double>) = quantity(quantity.orElse(null) as Double?)
 
             /** An optional quantity credited. */
             fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -655,7 +739,21 @@ private constructor(
 
             /** Any tax amounts applied onto the line item. */
             fun taxAmounts(taxAmounts: JsonField<List<TaxAmount>>) = apply {
-                this.taxAmounts = taxAmounts
+                this.taxAmounts = taxAmounts.map { it.toMutableList() }
+            }
+
+            /** Any tax amounts applied onto the line item. */
+            fun addTaxAmount(taxAmount: TaxAmount) = apply {
+                taxAmounts =
+                    (taxAmounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(taxAmount)
+                    }
             }
 
             /** Any line item discounts from the invoice's line item. */
@@ -663,7 +761,21 @@ private constructor(
 
             /** Any line item discounts from the invoice's line item. */
             fun discounts(discounts: JsonField<List<Discount>>) = apply {
-                this.discounts = discounts
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
+            /** Any line item discounts from the invoice's line item. */
+            fun addDiscount(discount: Discount) = apply {
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -687,13 +799,14 @@ private constructor(
 
             fun build(): LineItem =
                 LineItem(
-                    id,
-                    amount,
-                    name,
-                    quantity,
-                    subtotal,
-                    taxAmounts.map { it.toImmutable() },
-                    discounts.map { it.toImmutable() },
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(taxAmounts) { "`taxAmounts` is required but was not set" }
+                        .map { it.toImmutable() },
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -727,17 +840,17 @@ private constructor(
                 Optional.ofNullable(taxRatePercentage.getNullable("tax_rate_percentage"))
 
             /** The amount of additional tax incurred by this tax rate. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
             /** The human-readable description of the applied tax rate. */
             @JsonProperty("tax_rate_description")
             @ExcludeMissing
-            fun _taxRateDescription() = taxRateDescription
+            fun _taxRateDescription(): JsonField<String> = taxRateDescription
 
             /** The tax rate percentage, out of 100. */
             @JsonProperty("tax_rate_percentage")
             @ExcludeMissing
-            fun _taxRatePercentage() = taxRatePercentage
+            fun _taxRatePercentage(): JsonField<String> = taxRatePercentage
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -763,9 +876,9 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var taxRateDescription: JsonField<String> = JsonMissing.of()
-                private var taxRatePercentage: JsonField<String> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var taxRateDescription: JsonField<String>? = null
+                private var taxRatePercentage: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -792,8 +905,12 @@ private constructor(
                 }
 
                 /** The tax rate percentage, out of 100. */
-                fun taxRatePercentage(taxRatePercentage: String) =
-                    taxRatePercentage(JsonField.of(taxRatePercentage))
+                fun taxRatePercentage(taxRatePercentage: String?) =
+                    taxRatePercentage(JsonField.ofNullable(taxRatePercentage))
+
+                /** The tax rate percentage, out of 100. */
+                fun taxRatePercentage(taxRatePercentage: Optional<String>) =
+                    taxRatePercentage(taxRatePercentage.orElse(null))
 
                 /** The tax rate percentage, out of 100. */
                 fun taxRatePercentage(taxRatePercentage: JsonField<String>) = apply {
@@ -824,9 +941,13 @@ private constructor(
 
                 fun build(): TaxAmount =
                     TaxAmount(
-                        amount,
-                        taxRateDescription,
-                        taxRatePercentage,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(taxRateDescription) {
+                            "`taxRateDescription` is required but was not set"
+                        },
+                        checkNotNull(taxRatePercentage) {
+                            "`taxRatePercentage` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -894,23 +1015,29 @@ private constructor(
 
             fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("amount_applied") @ExcludeMissing fun _amountApplied() = amountApplied
+            @JsonProperty("amount_applied")
+            @ExcludeMissing
+            fun _amountApplied(): JsonField<String> = amountApplied
 
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -940,11 +1067,11 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var amountApplied: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var amountApplied: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var percentageDiscount: JsonField<Double>? = null
                 private var amountDiscount: JsonField<String> = JsonMissing.of()
                 private var reason: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -953,7 +1080,7 @@ private constructor(
                 internal fun from(discount: Discount) = apply {
                     id = discount.id
                     amountApplied = discount.amountApplied
-                    appliesToPriceIds = discount.appliesToPriceIds
+                    appliesToPriceIds = discount.appliesToPriceIds.map { it.toMutableList() }
                     discountType = discount.discountType
                     percentageDiscount = discount.percentageDiscount
                     amountDiscount = discount.amountDiscount
@@ -976,7 +1103,20 @@ private constructor(
                     appliesToPriceIds(JsonField.of(appliesToPriceIds))
 
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 fun discountType(discountType: DiscountType) =
@@ -993,14 +1133,19 @@ private constructor(
                     this.percentageDiscount = percentageDiscount
                 }
 
-                fun amountDiscount(amountDiscount: String) =
-                    amountDiscount(JsonField.of(amountDiscount))
+                fun amountDiscount(amountDiscount: String?) =
+                    amountDiscount(JsonField.ofNullable(amountDiscount))
+
+                fun amountDiscount(amountDiscount: Optional<String>) =
+                    amountDiscount(amountDiscount.orElse(null))
 
                 fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                     this.amountDiscount = amountDiscount
                 }
 
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -1028,11 +1173,18 @@ private constructor(
 
                 fun build(): Discount =
                     Discount(
-                        id,
-                        amountApplied,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        discountType,
-                        percentageDiscount,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(amountApplied) {
+                            "`amountApplied` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
                         amountDiscount,
                         reason,
                         additionalProperties.toImmutable(),
@@ -1167,17 +1319,23 @@ private constructor(
 
         fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-        @JsonProperty("amount_applied") @ExcludeMissing fun _amountApplied() = amountApplied
+        @JsonProperty("amount_applied")
+        @ExcludeMissing
+        fun _amountApplied(): JsonField<String> = amountApplied
 
-        @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+        @JsonProperty("discount_type")
+        @ExcludeMissing
+        fun _discountType(): JsonField<DiscountType> = discountType
 
         @JsonProperty("percentage_discount")
         @ExcludeMissing
-        fun _percentageDiscount() = percentageDiscount
+        fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
-        @JsonProperty("applies_to_prices") @ExcludeMissing fun _appliesToPrices() = appliesToPrices
+        @JsonProperty("applies_to_prices")
+        @ExcludeMissing
+        fun _appliesToPrices(): JsonField<List<AppliesToPrice>> = appliesToPrices
 
-        @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1205,10 +1363,10 @@ private constructor(
 
         class Builder {
 
-            private var amountApplied: JsonField<String> = JsonMissing.of()
-            private var discountType: JsonField<DiscountType> = JsonMissing.of()
-            private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-            private var appliesToPrices: JsonField<List<AppliesToPrice>> = JsonMissing.of()
+            private var amountApplied: JsonField<String>? = null
+            private var discountType: JsonField<DiscountType>? = null
+            private var percentageDiscount: JsonField<Double>? = null
+            private var appliesToPrices: JsonField<MutableList<AppliesToPrice>>? = null
             private var reason: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -1217,7 +1375,7 @@ private constructor(
                 amountApplied = maximumAmountAdjustment.amountApplied
                 discountType = maximumAmountAdjustment.discountType
                 percentageDiscount = maximumAmountAdjustment.percentageDiscount
-                appliesToPrices = maximumAmountAdjustment.appliesToPrices
+                appliesToPrices = maximumAmountAdjustment.appliesToPrices.map { it.toMutableList() }
                 reason = maximumAmountAdjustment.reason
                 additionalProperties = maximumAmountAdjustment.additionalProperties.toMutableMap()
             }
@@ -1241,14 +1399,32 @@ private constructor(
                 this.percentageDiscount = percentageDiscount
             }
 
-            fun appliesToPrices(appliesToPrices: List<AppliesToPrice>) =
-                appliesToPrices(JsonField.of(appliesToPrices))
+            fun appliesToPrices(appliesToPrices: List<AppliesToPrice>?) =
+                appliesToPrices(JsonField.ofNullable(appliesToPrices))
+
+            fun appliesToPrices(appliesToPrices: Optional<List<AppliesToPrice>>) =
+                appliesToPrices(appliesToPrices.orElse(null))
 
             fun appliesToPrices(appliesToPrices: JsonField<List<AppliesToPrice>>) = apply {
-                this.appliesToPrices = appliesToPrices
+                this.appliesToPrices = appliesToPrices.map { it.toMutableList() }
+            }
+
+            fun addAppliesToPrice(appliesToPrice: AppliesToPrice) = apply {
+                appliesToPrices =
+                    (appliesToPrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPrice)
+                    }
             }
 
-            fun reason(reason: String) = reason(JsonField.of(reason))
+            fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+            fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
             fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -1273,10 +1449,12 @@ private constructor(
 
             fun build(): MaximumAmountAdjustment =
                 MaximumAmountAdjustment(
-                    amountApplied,
-                    discountType,
-                    percentageDiscount,
-                    appliesToPrices.map { it.toImmutable() },
+                    checkNotNull(amountApplied) { "`amountApplied` is required but was not set" },
+                    checkNotNull(discountType) { "`discountType` is required but was not set" },
+                    checkNotNull(percentageDiscount) {
+                        "`percentageDiscount` is required but was not set"
+                    },
+                    (appliesToPrices ?: JsonMissing.of()).map { it.toImmutable() },
                     reason,
                     additionalProperties.toImmutable(),
                 )
@@ -1351,9 +1529,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1378,8 +1556,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1421,8 +1599,8 @@ private constructor(
 
                 fun build(): AppliesToPrice =
                     AppliesToPrice(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1623,17 +1801,23 @@ private constructor(
 
         fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-        @JsonProperty("amount_applied") @ExcludeMissing fun _amountApplied() = amountApplied
+        @JsonProperty("amount_applied")
+        @ExcludeMissing
+        fun _amountApplied(): JsonField<String> = amountApplied
 
-        @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+        @JsonProperty("discount_type")
+        @ExcludeMissing
+        fun _discountType(): JsonField<DiscountType> = discountType
 
         @JsonProperty("percentage_discount")
         @ExcludeMissing
-        fun _percentageDiscount() = percentageDiscount
+        fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
-        @JsonProperty("applies_to_prices") @ExcludeMissing fun _appliesToPrices() = appliesToPrices
+        @JsonProperty("applies_to_prices")
+        @ExcludeMissing
+        fun _appliesToPrices(): JsonField<List<AppliesToPrice>> = appliesToPrices
 
-        @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1661,10 +1845,10 @@ private constructor(
 
         class Builder {
 
-            private var amountApplied: JsonField<String> = JsonMissing.of()
-            private var discountType: JsonField<DiscountType> = JsonMissing.of()
-            private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-            private var appliesToPrices: JsonField<List<AppliesToPrice>> = JsonMissing.of()
+            private var amountApplied: JsonField<String>? = null
+            private var discountType: JsonField<DiscountType>? = null
+            private var percentageDiscount: JsonField<Double>? = null
+            private var appliesToPrices: JsonField<MutableList<AppliesToPrice>>? = null
             private var reason: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -1673,7 +1857,7 @@ private constructor(
                 amountApplied = discount.amountApplied
                 discountType = discount.discountType
                 percentageDiscount = discount.percentageDiscount
-                appliesToPrices = discount.appliesToPrices
+                appliesToPrices = discount.appliesToPrices.map { it.toMutableList() }
                 reason = discount.reason
                 additionalProperties = discount.additionalProperties.toMutableMap()
             }
@@ -1697,14 +1881,32 @@ private constructor(
                 this.percentageDiscount = percentageDiscount
             }
 
-            fun appliesToPrices(appliesToPrices: List<AppliesToPrice>) =
-                appliesToPrices(JsonField.of(appliesToPrices))
+            fun appliesToPrices(appliesToPrices: List<AppliesToPrice>?) =
+                appliesToPrices(JsonField.ofNullable(appliesToPrices))
+
+            fun appliesToPrices(appliesToPrices: Optional<List<AppliesToPrice>>) =
+                appliesToPrices(appliesToPrices.orElse(null))
 
             fun appliesToPrices(appliesToPrices: JsonField<List<AppliesToPrice>>) = apply {
-                this.appliesToPrices = appliesToPrices
+                this.appliesToPrices = appliesToPrices.map { it.toMutableList() }
+            }
+
+            fun addAppliesToPrice(appliesToPrice: AppliesToPrice) = apply {
+                appliesToPrices =
+                    (appliesToPrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPrice)
+                    }
             }
 
-            fun reason(reason: String) = reason(JsonField.of(reason))
+            fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+            fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
             fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -1729,10 +1931,12 @@ private constructor(
 
             fun build(): Discount =
                 Discount(
-                    amountApplied,
-                    discountType,
-                    percentageDiscount,
-                    appliesToPrices.map { it.toImmutable() },
+                    checkNotNull(amountApplied) { "`amountApplied` is required but was not set" },
+                    checkNotNull(discountType) { "`discountType` is required but was not set" },
+                    checkNotNull(percentageDiscount) {
+                        "`percentageDiscount` is required but was not set"
+                    },
+                    (appliesToPrices ?: JsonMissing.of()).map { it.toImmutable() },
                     reason,
                     additionalProperties.toImmutable(),
                 )
@@ -1807,9 +2011,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1834,8 +2038,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1877,8 +2081,8 @@ private constructor(
 
                 fun build(): AppliesToPrice =
                     AppliesToPrice(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteCreateParams.kt
index 3d26c038..fe6f6d13 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteCreateParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,7 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/** This endpoint is used to create a single [`Credit Note`](../guides/invoicing/credit-notes). */
 class CreditNoteCreateParams
 constructor(
     private val body: CreditNoteCreateBody,
@@ -34,12 +36,20 @@ constructor(
     /** An optional reason for the credit note. */
     fun reason(): Optional<Reason> = body.reason()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _lineItems(): JsonField<List<LineItem>> = body._lineItems()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** An optional memo to attach to the credit note. */
+    fun _memo(): JsonField<String> = body._memo()
+
+    /** An optional reason for the credit note. */
+    fun _reason(): JsonField<Reason> = body._reason()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CreditNoteCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -50,25 +60,52 @@ constructor(
     class CreditNoteCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("line_items") private val lineItems: List<LineItem>,
-        @JsonProperty("memo") private val memo: String?,
-        @JsonProperty("reason") private val reason: Reason?,
+        @JsonProperty("line_items")
+        @ExcludeMissing
+        private val lineItems: JsonField<List<LineItem>> = JsonMissing.of(),
+        @JsonProperty("memo")
+        @ExcludeMissing
+        private val memo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("reason")
+        @ExcludeMissing
+        private val reason: JsonField<Reason> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("line_items") fun lineItems(): List<LineItem> = lineItems
+        fun lineItems(): List<LineItem> = lineItems.getRequired("line_items")
 
         /** An optional memo to attach to the credit note. */
-        @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+        fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
 
         /** An optional reason for the credit note. */
-        @JsonProperty("reason") fun reason(): Optional<Reason> = Optional.ofNullable(reason)
+        fun reason(): Optional<Reason> = Optional.ofNullable(reason.getNullable("reason"))
+
+        @JsonProperty("line_items")
+        @ExcludeMissing
+        fun _lineItems(): JsonField<List<LineItem>> = lineItems
+
+        /** An optional memo to attach to the credit note. */
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
+
+        /** An optional reason for the credit note. */
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<Reason> = reason
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CreditNoteCreateBody = apply {
+            if (!validated) {
+                lineItems().forEach { it.validate() }
+                memo()
+                reason()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -78,39 +115,56 @@ constructor(
 
         class Builder {
 
-            private var lineItems: MutableList<LineItem>? = null
-            private var memo: String? = null
-            private var reason: Reason? = null
+            private var lineItems: JsonField<MutableList<LineItem>>? = null
+            private var memo: JsonField<String> = JsonMissing.of()
+            private var reason: JsonField<Reason> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(creditNoteCreateBody: CreditNoteCreateBody) = apply {
-                lineItems = creditNoteCreateBody.lineItems.toMutableList()
+                lineItems = creditNoteCreateBody.lineItems.map { it.toMutableList() }
                 memo = creditNoteCreateBody.memo
                 reason = creditNoteCreateBody.reason
                 additionalProperties = creditNoteCreateBody.additionalProperties.toMutableMap()
             }
 
-            fun lineItems(lineItems: List<LineItem>) = apply {
-                this.lineItems = lineItems.toMutableList()
+            fun lineItems(lineItems: List<LineItem>) = lineItems(JsonField.of(lineItems))
+
+            fun lineItems(lineItems: JsonField<List<LineItem>>) = apply {
+                this.lineItems = lineItems.map { it.toMutableList() }
             }
 
             fun addLineItem(lineItem: LineItem) = apply {
-                lineItems = (lineItems ?: mutableListOf()).apply { add(lineItem) }
+                lineItems =
+                    (lineItems ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(lineItem)
+                    }
             }
 
             /** An optional memo to attach to the credit note. */
-            fun memo(memo: String?) = apply { this.memo = memo }
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
             /** An optional memo to attach to the credit note. */
             fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
+            /** An optional memo to attach to the credit note. */
+            fun memo(memo: JsonField<String>) = apply { this.memo = memo }
+
             /** An optional reason for the credit note. */
-            fun reason(reason: Reason?) = apply { this.reason = reason }
+            fun reason(reason: Reason?) = reason(JsonField.ofNullable(reason))
 
             /** An optional reason for the credit note. */
             fun reason(reason: Optional<Reason>) = reason(reason.orElse(null))
 
+            /** An optional reason for the credit note. */
+            fun reason(reason: JsonField<Reason>) = apply { this.reason = reason }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -133,7 +187,7 @@ constructor(
             fun build(): CreditNoteCreateBody =
                 CreditNoteCreateBody(
                     checkNotNull(lineItems) { "`lineItems` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     memo,
                     reason,
                     additionalProperties.toImmutable(),
@@ -181,6 +235,8 @@ constructor(
 
         fun lineItems(lineItems: List<LineItem>) = apply { body.lineItems(lineItems) }
 
+        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply { body.lineItems(lineItems) }
+
         fun addLineItem(lineItem: LineItem) = apply { body.addLineItem(lineItem) }
 
         /** An optional memo to attach to the credit note. */
@@ -189,12 +245,37 @@ constructor(
         /** An optional memo to attach to the credit note. */
         fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
+        /** An optional memo to attach to the credit note. */
+        fun memo(memo: JsonField<String>) = apply { body.memo(memo) }
+
         /** An optional reason for the credit note. */
         fun reason(reason: Reason?) = apply { body.reason(reason) }
 
         /** An optional reason for the credit note. */
         fun reason(reason: Optional<Reason>) = reason(reason.orElse(null))
 
+        /** An optional reason for the credit note. */
+        fun reason(reason: JsonField<Reason>) = apply { body.reason(reason) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -293,25 +374,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CreditNoteCreateParams =
             CreditNoteCreateParams(
                 body.build(),
@@ -324,22 +386,44 @@ constructor(
     class LineItem
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: String,
-        @JsonProperty("invoice_line_item_id") private val invoiceLineItemId: String,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoice_line_item_id")
+        @ExcludeMissing
+        private val invoiceLineItemId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The total amount in the invoice's currency to credit this line item. */
-        @JsonProperty("amount") fun amount(): String = amount
+        fun amount(): String = amount.getRequired("amount")
 
         /** The ID of the line item to credit. */
-        @JsonProperty("invoice_line_item_id") fun invoiceLineItemId(): String = invoiceLineItemId
+        fun invoiceLineItemId(): String = invoiceLineItemId.getRequired("invoice_line_item_id")
+
+        /** The total amount in the invoice's currency to credit this line item. */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
+
+        /** The ID of the line item to credit. */
+        @JsonProperty("invoice_line_item_id")
+        @ExcludeMissing
+        fun _invoiceLineItemId(): JsonField<String> = invoiceLineItemId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): LineItem = apply {
+            if (!validated) {
+                amount()
+                invoiceLineItemId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -349,8 +433,8 @@ constructor(
 
         class Builder {
 
-            private var amount: String? = null
-            private var invoiceLineItemId: String? = null
+            private var amount: JsonField<String>? = null
+            private var invoiceLineItemId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -361,10 +445,17 @@ constructor(
             }
 
             /** The total amount in the invoice's currency to credit this line item. */
-            fun amount(amount: String) = apply { this.amount = amount }
+            fun amount(amount: String) = amount(JsonField.of(amount))
+
+            /** The total amount in the invoice's currency to credit this line item. */
+            fun amount(amount: JsonField<String>) = apply { this.amount = amount }
+
+            /** The ID of the line item to credit. */
+            fun invoiceLineItemId(invoiceLineItemId: String) =
+                invoiceLineItemId(JsonField.of(invoiceLineItemId))
 
             /** The ID of the line item to credit. */
-            fun invoiceLineItemId(invoiceLineItemId: String) = apply {
+            fun invoiceLineItemId(invoiceLineItemId: JsonField<String>) = apply {
                 this.invoiceLineItemId = invoiceLineItemId
             }
 
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteFetchParams.kt
index d61ea776..8bab5025 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteFetchParams.kt
@@ -7,6 +7,10 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch a single [`Credit Note`](../guides/invoicing/credit-notes) given
+ * an identifier.
+ */
 class CreditNoteFetchParams
 constructor(
     private val creditNoteId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteListParams.kt
index 4724e9eb..c7e1ca90 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CreditNoteListParams.kt
@@ -8,6 +8,11 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Get a paginated list of CreditNotes. Users can also filter by customer_id, subscription_id, or
+ * external_customer_id. The credit notes will be returned in reverse chronological order by
+ * `creation_time`.
+ */
 class CreditNoteListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Customer.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Customer.kt
index bc43cd06..7b11965f 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Customer.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Customer.kt
@@ -287,32 +287,42 @@ private constructor(
     fun reportingConfiguration(): Optional<ReportingConfiguration> =
         Optional.ofNullable(reportingConfiguration.getNullable("reporting_configuration"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("additional_emails") @ExcludeMissing fun _additionalEmails() = additionalEmails
+    @JsonProperty("additional_emails")
+    @ExcludeMissing
+    fun _additionalEmails(): JsonField<List<String>> = additionalEmails
 
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     /** The customer's current balance in their currency. */
-    @JsonProperty("balance") @ExcludeMissing fun _balance() = balance
+    @JsonProperty("balance") @ExcludeMissing fun _balance(): JsonField<String> = balance
 
-    @JsonProperty("billing_address") @ExcludeMissing fun _billingAddress() = billingAddress
+    @JsonProperty("billing_address")
+    @ExcludeMissing
+    fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /**
      * A valid customer email, to be used for notifications. When Orb triggers payment through a
      * payment gateway, this email will be used for any automatically issued receipts.
      */
-    @JsonProperty("email") @ExcludeMissing fun _email() = email
+    @JsonProperty("email") @ExcludeMissing fun _email(): JsonField<String> = email
 
-    @JsonProperty("email_delivery") @ExcludeMissing fun _emailDelivery() = emailDelivery
+    @JsonProperty("email_delivery")
+    @ExcludeMissing
+    fun _emailDelivery(): JsonField<Boolean> = emailDelivery
 
     @JsonProperty("exempt_from_automated_tax")
     @ExcludeMissing
-    fun _exemptFromAutomatedTax() = exemptFromAutomatedTax
+    fun _exemptFromAutomatedTax(): JsonField<Boolean> = exemptFromAutomatedTax
 
     /**
      * An optional user-defined ID for this customer resource, used throughout the system as an
@@ -321,23 +331,25 @@ private constructor(
      */
     @JsonProperty("external_customer_id")
     @ExcludeMissing
-    fun _externalCustomerId() = externalCustomerId
+    fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The full name of the customer */
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
     /**
      * This is used for creating charges or invoices in an external system via Orb. When not in test
      * mode, the connection must first be configured in the Orb webapp.
      */
-    @JsonProperty("payment_provider") @ExcludeMissing fun _paymentProvider() = paymentProvider
+    @JsonProperty("payment_provider")
+    @ExcludeMissing
+    fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
     /**
      * The ID of this customer in an external payments solution, such as Stripe. This is used for
@@ -345,11 +357,13 @@ private constructor(
      */
     @JsonProperty("payment_provider_id")
     @ExcludeMissing
-    fun _paymentProviderId() = paymentProviderId
+    fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
-    @JsonProperty("portal_url") @ExcludeMissing fun _portalUrl() = portalUrl
+    @JsonProperty("portal_url") @ExcludeMissing fun _portalUrl(): JsonField<String> = portalUrl
 
-    @JsonProperty("shipping_address") @ExcludeMissing fun _shippingAddress() = shippingAddress
+    @JsonProperty("shipping_address")
+    @ExcludeMissing
+    fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
     /**
      * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
@@ -457,22 +471,23 @@ private constructor(
      * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
      * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
      */
-    @JsonProperty("tax_id") @ExcludeMissing fun _taxId() = taxId
+    @JsonProperty("tax_id") @ExcludeMissing fun _taxId(): JsonField<TaxId> = taxId
 
     /**
      * A timezone identifier from the IANA timezone database, such as "America/Los_Angeles". This
      * "defaults to your account's timezone if not set. This cannot be changed after customer
      * creation.
      */
-    @JsonProperty("timezone") @ExcludeMissing fun _timezone() = timezone
+    @JsonProperty("timezone") @ExcludeMissing fun _timezone(): JsonField<String> = timezone
 
     @JsonProperty("accounting_sync_configuration")
     @ExcludeMissing
-    fun _accountingSyncConfiguration() = accountingSyncConfiguration
+    fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+        accountingSyncConfiguration
 
     @JsonProperty("reporting_configuration")
     @ExcludeMissing
-    fun _reportingConfiguration() = reportingConfiguration
+    fun _reportingConfiguration(): JsonField<ReportingConfiguration> = reportingConfiguration
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -516,25 +531,25 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var additionalEmails: JsonField<List<String>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var balance: JsonField<String> = JsonMissing.of()
-        private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var email: JsonField<String> = JsonMissing.of()
-        private var emailDelivery: JsonField<Boolean> = JsonMissing.of()
-        private var exemptFromAutomatedTax: JsonField<Boolean> = JsonMissing.of()
-        private var externalCustomerId: JsonField<String> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
-        private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
-        private var paymentProviderId: JsonField<String> = JsonMissing.of()
-        private var portalUrl: JsonField<String> = JsonMissing.of()
-        private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
-        private var taxId: JsonField<TaxId> = JsonMissing.of()
-        private var timezone: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var additionalEmails: JsonField<MutableList<String>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var balance: JsonField<String>? = null
+        private var billingAddress: JsonField<BillingAddress>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currency: JsonField<String>? = null
+        private var email: JsonField<String>? = null
+        private var emailDelivery: JsonField<Boolean>? = null
+        private var exemptFromAutomatedTax: JsonField<Boolean>? = null
+        private var externalCustomerId: JsonField<String>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var name: JsonField<String>? = null
+        private var paymentProvider: JsonField<PaymentProvider>? = null
+        private var paymentProviderId: JsonField<String>? = null
+        private var portalUrl: JsonField<String>? = null
+        private var shippingAddress: JsonField<ShippingAddress>? = null
+        private var taxId: JsonField<TaxId>? = null
+        private var timezone: JsonField<String>? = null
         private var accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
             JsonMissing.of()
         private var reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of()
@@ -543,7 +558,7 @@ private constructor(
         @JvmSynthetic
         internal fun from(customer: Customer) = apply {
             id = customer.id
-            additionalEmails = customer.additionalEmails
+            additionalEmails = customer.additionalEmails.map { it.toMutableList() }
             autoCollection = customer.autoCollection
             balance = customer.balance
             billingAddress = customer.billingAddress
@@ -574,7 +589,20 @@ private constructor(
             additionalEmails(JsonField.of(additionalEmails))
 
         fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
-            this.additionalEmails = additionalEmails
+            this.additionalEmails = additionalEmails.map { it.toMutableList() }
+        }
+
+        fun addAdditionalEmail(additionalEmail: String) = apply {
+            additionalEmails =
+                (additionalEmails ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(additionalEmail)
+                }
         }
 
         fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
@@ -589,8 +617,11 @@ private constructor(
         /** The customer's current balance in their currency. */
         fun balance(balance: JsonField<String>) = apply { this.balance = balance }
 
-        fun billingAddress(billingAddress: BillingAddress) =
-            billingAddress(JsonField.of(billingAddress))
+        fun billingAddress(billingAddress: BillingAddress?) =
+            billingAddress(JsonField.ofNullable(billingAddress))
+
+        fun billingAddress(billingAddress: Optional<BillingAddress>) =
+            billingAddress(billingAddress.orElse(null))
 
         fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
             this.billingAddress = billingAddress
@@ -600,7 +631,9 @@ private constructor(
 
         fun createdAt(createdAt: JsonField<OffsetDateTime>) = apply { this.createdAt = createdAt }
 
-        fun currency(currency: String) = currency(JsonField.of(currency))
+        fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
+
+        fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
         fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
@@ -622,8 +655,15 @@ private constructor(
             this.emailDelivery = emailDelivery
         }
 
+        fun exemptFromAutomatedTax(exemptFromAutomatedTax: Boolean?) =
+            exemptFromAutomatedTax(JsonField.ofNullable(exemptFromAutomatedTax))
+
         fun exemptFromAutomatedTax(exemptFromAutomatedTax: Boolean) =
-            exemptFromAutomatedTax(JsonField.of(exemptFromAutomatedTax))
+            exemptFromAutomatedTax(exemptFromAutomatedTax as Boolean?)
+
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun exemptFromAutomatedTax(exemptFromAutomatedTax: Optional<Boolean>) =
+            exemptFromAutomatedTax(exemptFromAutomatedTax.orElse(null) as Boolean?)
 
         fun exemptFromAutomatedTax(exemptFromAutomatedTax: JsonField<Boolean>) = apply {
             this.exemptFromAutomatedTax = exemptFromAutomatedTax
@@ -634,8 +674,16 @@ private constructor(
          * alias for this Customer. Use this field to identify a customer by an existing identifier
          * in your system.
          */
-        fun externalCustomerId(externalCustomerId: String) =
-            externalCustomerId(JsonField.of(externalCustomerId))
+        fun externalCustomerId(externalCustomerId: String?) =
+            externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+        /**
+         * An optional user-defined ID for this customer resource, used throughout the system as an
+         * alias for this Customer. Use this field to identify a customer by an existing identifier
+         * in your system.
+         */
+        fun externalCustomerId(externalCustomerId: Optional<String>) =
+            externalCustomerId(externalCustomerId.orElse(null))
 
         /**
          * An optional user-defined ID for this customer resource, used throughout the system as an
@@ -670,8 +718,15 @@ private constructor(
          * This is used for creating charges or invoices in an external system via Orb. When not in
          * test mode, the connection must first be configured in the Orb webapp.
          */
-        fun paymentProvider(paymentProvider: PaymentProvider) =
-            paymentProvider(JsonField.of(paymentProvider))
+        fun paymentProvider(paymentProvider: PaymentProvider?) =
+            paymentProvider(JsonField.ofNullable(paymentProvider))
+
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode, the connection must first be configured in the Orb webapp.
+         */
+        fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
+            paymentProvider(paymentProvider.orElse(null))
 
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
@@ -685,8 +740,15 @@ private constructor(
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
-        fun paymentProviderId(paymentProviderId: String) =
-            paymentProviderId(JsonField.of(paymentProviderId))
+        fun paymentProviderId(paymentProviderId: String?) =
+            paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(paymentProviderId: Optional<String>) =
+            paymentProviderId(paymentProviderId.orElse(null))
 
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
@@ -696,12 +758,17 @@ private constructor(
             this.paymentProviderId = paymentProviderId
         }
 
-        fun portalUrl(portalUrl: String) = portalUrl(JsonField.of(portalUrl))
+        fun portalUrl(portalUrl: String?) = portalUrl(JsonField.ofNullable(portalUrl))
+
+        fun portalUrl(portalUrl: Optional<String>) = portalUrl(portalUrl.orElse(null))
 
         fun portalUrl(portalUrl: JsonField<String>) = apply { this.portalUrl = portalUrl }
 
-        fun shippingAddress(shippingAddress: ShippingAddress) =
-            shippingAddress(JsonField.of(shippingAddress))
+        fun shippingAddress(shippingAddress: ShippingAddress?) =
+            shippingAddress(JsonField.ofNullable(shippingAddress))
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
 
         fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
             this.shippingAddress = shippingAddress
@@ -813,7 +880,115 @@ private constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: TaxId) = taxId(JsonField.of(taxId))
+        fun taxId(taxId: TaxId?) = taxId(JsonField.ofNullable(taxId))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -937,15 +1112,22 @@ private constructor(
          */
         fun timezone(timezone: JsonField<String>) = apply { this.timezone = timezone }
 
-        fun accountingSyncConfiguration(accountingSyncConfiguration: AccountingSyncConfiguration) =
-            accountingSyncConfiguration(JsonField.of(accountingSyncConfiguration))
+        fun accountingSyncConfiguration(accountingSyncConfiguration: AccountingSyncConfiguration?) =
+            accountingSyncConfiguration(JsonField.ofNullable(accountingSyncConfiguration))
+
+        fun accountingSyncConfiguration(
+            accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
+        ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
         fun accountingSyncConfiguration(
             accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
         ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
 
-        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration) =
-            reportingConfiguration(JsonField.of(reportingConfiguration))
+        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) =
+            reportingConfiguration(JsonField.ofNullable(reportingConfiguration))
+
+        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+            reportingConfiguration(reportingConfiguration.orElse(null))
 
         fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
             apply {
@@ -973,25 +1155,32 @@ private constructor(
 
         fun build(): Customer =
             Customer(
-                id,
-                additionalEmails.map { it.toImmutable() },
-                autoCollection,
-                balance,
-                billingAddress,
-                createdAt,
-                currency,
-                email,
-                emailDelivery,
-                exemptFromAutomatedTax,
-                externalCustomerId,
-                metadata,
-                name,
-                paymentProvider,
-                paymentProviderId,
-                portalUrl,
-                shippingAddress,
-                taxId,
-                timezone,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(additionalEmails) { "`additionalEmails` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(balance) { "`balance` is required but was not set" },
+                checkNotNull(billingAddress) { "`billingAddress` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(email) { "`email` is required but was not set" },
+                checkNotNull(emailDelivery) { "`emailDelivery` is required but was not set" },
+                checkNotNull(exemptFromAutomatedTax) {
+                    "`exemptFromAutomatedTax` is required but was not set"
+                },
+                checkNotNull(externalCustomerId) {
+                    "`externalCustomerId` is required but was not set"
+                },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(name) { "`name` is required but was not set" },
+                checkNotNull(paymentProvider) { "`paymentProvider` is required but was not set" },
+                checkNotNull(paymentProviderId) {
+                    "`paymentProviderId` is required but was not set"
+                },
+                checkNotNull(portalUrl) { "`portalUrl` is required but was not set" },
+                checkNotNull(shippingAddress) { "`shippingAddress` is required but was not set" },
+                checkNotNull(taxId) { "`taxId` is required but was not set" },
+                checkNotNull(timezone) { "`timezone` is required but was not set" },
                 accountingSyncConfiguration,
                 reportingConfiguration,
                 additionalProperties.toImmutable(),
@@ -1037,17 +1226,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1076,12 +1267,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1095,27 +1286,39 @@ private constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -1140,12 +1343,12 @@ private constructor(
 
             fun build(): BillingAddress =
                 BillingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1362,17 +1565,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1401,12 +1606,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1420,27 +1625,39 @@ private constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -1465,12 +1682,12 @@ private constructor(
 
             fun build(): ShippingAddress =
                 ShippingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1620,11 +1837,11 @@ private constructor(
 
         fun value(): String = value.getRequired("value")
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
-        @JsonProperty("value") @ExcludeMissing fun _value() = value
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1650,9 +1867,9 @@ private constructor(
 
         class Builder {
 
-            private var country: JsonField<Country> = JsonMissing.of()
-            private var type: JsonField<Type> = JsonMissing.of()
-            private var value: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1696,9 +1913,9 @@ private constructor(
 
             fun build(): TaxId =
                 TaxId(
-                    country,
-                    type,
-                    value,
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(type) { "`type` is required but was not set" },
+                    checkNotNull(value) { "`value` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2726,9 +2943,9 @@ private constructor(
 
         @JsonProperty("accounting_providers")
         @ExcludeMissing
-        fun _accountingProviders() = accountingProviders
+        fun _accountingProviders(): JsonField<List<AccountingProvider>> = accountingProviders
 
-        @JsonProperty("excluded") @ExcludeMissing fun _excluded() = excluded
+        @JsonProperty("excluded") @ExcludeMissing fun _excluded(): JsonField<Boolean> = excluded
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2753,13 +2970,14 @@ private constructor(
 
         class Builder {
 
-            private var accountingProviders: JsonField<List<AccountingProvider>> = JsonMissing.of()
-            private var excluded: JsonField<Boolean> = JsonMissing.of()
+            private var accountingProviders: JsonField<MutableList<AccountingProvider>>? = null
+            private var excluded: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(accountingSyncConfiguration: AccountingSyncConfiguration) = apply {
-                accountingProviders = accountingSyncConfiguration.accountingProviders
+                accountingProviders =
+                    accountingSyncConfiguration.accountingProviders.map { it.toMutableList() }
                 excluded = accountingSyncConfiguration.excluded
                 additionalProperties =
                     accountingSyncConfiguration.additionalProperties.toMutableMap()
@@ -2770,9 +2988,22 @@ private constructor(
 
             fun accountingProviders(accountingProviders: JsonField<List<AccountingProvider>>) =
                 apply {
-                    this.accountingProviders = accountingProviders
+                    this.accountingProviders = accountingProviders.map { it.toMutableList() }
                 }
 
+            fun addAccountingProvider(accountingProvider: AccountingProvider) = apply {
+                accountingProviders =
+                    (accountingProviders ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(accountingProvider)
+                    }
+            }
+
             fun excluded(excluded: Boolean) = excluded(JsonField.of(excluded))
 
             fun excluded(excluded: JsonField<Boolean>) = apply { this.excluded = excluded }
@@ -2798,8 +3029,11 @@ private constructor(
 
             fun build(): AccountingSyncConfiguration =
                 AccountingSyncConfiguration(
-                    accountingProviders.map { it.toImmutable() },
-                    excluded,
+                    checkNotNull(accountingProviders) {
+                            "`accountingProviders` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(excluded) { "`excluded` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2825,9 +3059,11 @@ private constructor(
 
             @JsonProperty("external_provider_id")
             @ExcludeMissing
-            fun _externalProviderId() = externalProviderId
+            fun _externalProviderId(): JsonField<String> = externalProviderId
 
-            @JsonProperty("provider_type") @ExcludeMissing fun _providerType() = providerType
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            fun _providerType(): JsonField<ProviderType> = providerType
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2852,8 +3088,8 @@ private constructor(
 
             class Builder {
 
-                private var externalProviderId: JsonField<String> = JsonMissing.of()
-                private var providerType: JsonField<ProviderType> = JsonMissing.of()
+                private var externalProviderId: JsonField<String>? = null
+                private var providerType: JsonField<ProviderType>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2863,8 +3099,11 @@ private constructor(
                     additionalProperties = accountingProvider.additionalProperties.toMutableMap()
                 }
 
-                fun externalProviderId(externalProviderId: String) =
-                    externalProviderId(JsonField.of(externalProviderId))
+                fun externalProviderId(externalProviderId: String?) =
+                    externalProviderId(JsonField.ofNullable(externalProviderId))
+
+                fun externalProviderId(externalProviderId: Optional<String>) =
+                    externalProviderId(externalProviderId.orElse(null))
 
                 fun externalProviderId(externalProviderId: JsonField<String>) = apply {
                     this.externalProviderId = externalProviderId
@@ -2901,8 +3140,10 @@ private constructor(
 
                 fun build(): AccountingProvider =
                     AccountingProvider(
-                        externalProviderId,
-                        providerType,
+                        checkNotNull(externalProviderId) {
+                            "`externalProviderId` is required but was not set"
+                        },
+                        checkNotNull(providerType) { "`providerType` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3013,7 +3254,7 @@ private constructor(
 
         fun exempt(): Boolean = exempt.getRequired("exempt")
 
-        @JsonProperty("exempt") @ExcludeMissing fun _exempt() = exempt
+        @JsonProperty("exempt") @ExcludeMissing fun _exempt(): JsonField<Boolean> = exempt
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3037,7 +3278,7 @@ private constructor(
 
         class Builder {
 
-            private var exempt: JsonField<Boolean> = JsonMissing.of()
+            private var exempt: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3070,7 +3311,10 @@ private constructor(
             }
 
             fun build(): ReportingConfiguration =
-                ReportingConfiguration(exempt, additionalProperties.toImmutable())
+                ReportingConfiguration(
+                    checkNotNull(exempt) { "`exempt` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateParams.kt
index 02e3c23c..962aa8db 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,10 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Creates an immutable balance transaction that updates the customer's balance and returns back the
+ * newly created transaction.
+ */
 class CustomerBalanceTransactionCreateParams
 constructor(
     private val customerId: String,
@@ -36,12 +41,19 @@ constructor(
     /** An optional description that can be specified around this entry. */
     fun description(): Optional<String> = body.description()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _amount(): JsonField<String> = body._amount()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    fun _type(): JsonField<Type> = body._type()
+
+    /** An optional description that can be specified around this entry. */
+    fun _description(): JsonField<String> = body._description()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerBalanceTransactionCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -59,25 +71,49 @@ constructor(
     class CustomerBalanceTransactionCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("amount") private val amount: String,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("description") private val description: String?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("amount") fun amount(): String = amount
+        fun amount(): String = amount.getRequired("amount")
+
+        fun type(): Type = type.getRequired("type")
+
+        /** An optional description that can be specified around this entry. */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
         /** An optional description that can be specified around this entry. */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerBalanceTransactionCreateBody = apply {
+            if (!validated) {
+                amount()
+                type()
+                description()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -87,9 +123,9 @@ constructor(
 
         class Builder {
 
-            private var amount: String? = null
-            private var type: Type? = null
-            private var description: String? = null
+            private var amount: JsonField<String>? = null
+            private var type: JsonField<Type>? = null
+            private var description: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -103,16 +139,25 @@ constructor(
                     customerBalanceTransactionCreateBody.additionalProperties.toMutableMap()
             }
 
-            fun amount(amount: String) = apply { this.amount = amount }
+            fun amount(amount: String) = amount(JsonField.of(amount))
+
+            fun amount(amount: JsonField<String>) = apply { this.amount = amount }
+
+            fun type(type: Type) = type(JsonField.of(type))
 
-            fun type(type: Type) = apply { this.type = type }
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
             /** An optional description that can be specified around this entry. */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /** An optional description that can be specified around this entry. */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /** An optional description that can be specified around this entry. */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -190,14 +235,40 @@ constructor(
 
         fun amount(amount: String) = apply { body.amount(amount) }
 
+        fun amount(amount: JsonField<String>) = apply { body.amount(amount) }
+
         fun type(type: Type) = apply { body.type(type) }
 
+        fun type(type: JsonField<Type>) = apply { body.type(type) }
+
         /** An optional description that can be specified around this entry. */
         fun description(description: String?) = apply { body.description(description) }
 
         /** An optional description that can be specified around this entry. */
         fun description(description: Optional<String>) = description(description.orElse(null))
 
+        /** An optional description that can be specified around this entry. */
+        fun description(description: JsonField<String>) = apply { body.description(description) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -296,25 +367,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerBalanceTransactionCreateParams =
             CustomerBalanceTransactionCreateParams(
                 checkNotNull(customerId) { "`customerId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateResponse.kt
index 0bf92cb5..446e3a3e 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionCreateResponse.kt
@@ -86,35 +86,43 @@ private constructor(
     fun type(): Type = type.getRequired("type")
 
     /** A unique id for this transaction. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("action") @ExcludeMissing fun _action() = action
+    @JsonProperty("action") @ExcludeMissing fun _action(): JsonField<Action> = action
 
     /** The value of the amount changed in the transaction. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /** The creation time of this transaction. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-    @JsonProperty("credit_note") @ExcludeMissing fun _creditNote() = creditNote
+    @JsonProperty("credit_note")
+    @ExcludeMissing
+    fun _creditNote(): JsonField<CreditNote> = creditNote
 
     /** An optional description provided for manual customer balance adjustments. */
-    @JsonProperty("description") @ExcludeMissing fun _description() = description
+    @JsonProperty("description") @ExcludeMissing fun _description(): JsonField<String> = description
 
     /**
      * The new value of the customer's balance prior to the transaction, in the customer's currency.
      */
-    @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+    @JsonProperty("ending_balance")
+    @ExcludeMissing
+    fun _endingBalance(): JsonField<String> = endingBalance
 
-    @JsonProperty("invoice") @ExcludeMissing fun _invoice() = invoice
+    @JsonProperty("invoice") @ExcludeMissing fun _invoice(): JsonField<Invoice> = invoice
 
     /**
      * The original value of the customer's balance prior to the transaction, in the customer's
      * currency.
      */
-    @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+    @JsonProperty("starting_balance")
+    @ExcludeMissing
+    fun _startingBalance(): JsonField<String> = startingBalance
 
-    @JsonProperty("type") @ExcludeMissing fun _type() = type
+    @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -147,16 +155,16 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var action: JsonField<Action> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var creditNote: JsonField<CreditNote> = JsonMissing.of()
-        private var description: JsonField<String> = JsonMissing.of()
-        private var endingBalance: JsonField<String> = JsonMissing.of()
-        private var invoice: JsonField<Invoice> = JsonMissing.of()
-        private var startingBalance: JsonField<String> = JsonMissing.of()
-        private var type: JsonField<Type> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var action: JsonField<Action>? = null
+        private var amount: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var creditNote: JsonField<CreditNote>? = null
+        private var description: JsonField<String>? = null
+        private var endingBalance: JsonField<String>? = null
+        private var invoice: JsonField<Invoice>? = null
+        private var startingBalance: JsonField<String>? = null
+        private var type: JsonField<Type>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -199,12 +207,17 @@ private constructor(
         /** The creation time of this transaction. */
         fun createdAt(createdAt: JsonField<OffsetDateTime>) = apply { this.createdAt = createdAt }
 
-        fun creditNote(creditNote: CreditNote) = creditNote(JsonField.of(creditNote))
+        fun creditNote(creditNote: CreditNote?) = creditNote(JsonField.ofNullable(creditNote))
+
+        fun creditNote(creditNote: Optional<CreditNote>) = creditNote(creditNote.orElse(null))
 
         fun creditNote(creditNote: JsonField<CreditNote>) = apply { this.creditNote = creditNote }
 
         /** An optional description provided for manual customer balance adjustments. */
-        fun description(description: String) = description(JsonField.of(description))
+        fun description(description: String?) = description(JsonField.ofNullable(description))
+
+        /** An optional description provided for manual customer balance adjustments. */
+        fun description(description: Optional<String>) = description(description.orElse(null))
 
         /** An optional description provided for manual customer balance adjustments. */
         fun description(description: JsonField<String>) = apply { this.description = description }
@@ -223,7 +236,9 @@ private constructor(
             this.endingBalance = endingBalance
         }
 
-        fun invoice(invoice: Invoice) = invoice(JsonField.of(invoice))
+        fun invoice(invoice: Invoice?) = invoice(JsonField.ofNullable(invoice))
+
+        fun invoice(invoice: Optional<Invoice>) = invoice(invoice.orElse(null))
 
         fun invoice(invoice: JsonField<Invoice>) = apply { this.invoice = invoice }
 
@@ -267,16 +282,16 @@ private constructor(
 
         fun build(): CustomerBalanceTransactionCreateResponse =
             CustomerBalanceTransactionCreateResponse(
-                id,
-                action,
-                amount,
-                createdAt,
-                creditNote,
-                description,
-                endingBalance,
-                invoice,
-                startingBalance,
-                type,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(action) { "`action` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(creditNote) { "`creditNote` is required but was not set" },
+                checkNotNull(description) { "`description` is required but was not set" },
+                checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                checkNotNull(invoice) { "`invoice` is required but was not set" },
+                checkNotNull(startingBalance) { "`startingBalance` is required but was not set" },
+                checkNotNull(type) { "`type` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -387,7 +402,7 @@ private constructor(
         fun id(): String = id.getRequired("id")
 
         /** The id of the Credit note */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -411,7 +426,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -445,7 +460,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): CreditNote = CreditNote(id, additionalProperties.toImmutable())
+            fun build(): CreditNote =
+                CreditNote(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
@@ -478,7 +497,7 @@ private constructor(
         fun id(): String = id.getRequired("id")
 
         /** The Invoice id */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -502,7 +521,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -536,7 +555,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Invoice = Invoice(id, additionalProperties.toImmutable())
+            fun build(): Invoice =
+                Invoice(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListParams.kt
index eb971499..60559df1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListParams.kt
@@ -10,6 +10,32 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * ## The customer balance
+ *
+ * The customer balance is an amount in the customer's currency, which Orb automatically applies to
+ * subsequent invoices. This balance can be adjusted manually via Orb's webapp on the customer
+ * details page. You can use this balance to provide a fixed mid-period credit to the customer.
+ * Commonly, this is done due to system downtime/SLA violation, or an adhoc adjustment discussed
+ * with the customer.
+ *
+ * If the balance is a positive value at the time of invoicing, it represents that the customer has
+ * credit that should be used to offset the amount due on the next issued invoice. In this case, Orb
+ * will automatically reduce the next invoice by the balance amount, and roll over any remaining
+ * balance if the invoice is fully discounted.
+ *
+ * If the balance is a negative value at the time of invoicing, Orb will increase the invoice's
+ * amount due with a positive adjustment, and reset the balance to 0.
+ *
+ * This endpoint retrieves all customer balance transactions in reverse chronological order for a
+ * single customer, providing a complete audit trail of all adjustments and invoice applications.
+ *
+ * ## Eligibility
+ *
+ * The customer balance can only be applied to invoices or adjusted manually if invoices are not
+ * synced to a separate invoicing provider. If a payment gateway such as Stripe is used, the balance
+ * will be applied to the invoice before forwarding payment to the gateway.
+ */
 class CustomerBalanceTransactionListParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListResponse.kt
index 913835ca..c9b0f689 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerBalanceTransactionListResponse.kt
@@ -86,35 +86,43 @@ private constructor(
     fun type(): Type = type.getRequired("type")
 
     /** A unique id for this transaction. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("action") @ExcludeMissing fun _action() = action
+    @JsonProperty("action") @ExcludeMissing fun _action(): JsonField<Action> = action
 
     /** The value of the amount changed in the transaction. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /** The creation time of this transaction. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-    @JsonProperty("credit_note") @ExcludeMissing fun _creditNote() = creditNote
+    @JsonProperty("credit_note")
+    @ExcludeMissing
+    fun _creditNote(): JsonField<CreditNote> = creditNote
 
     /** An optional description provided for manual customer balance adjustments. */
-    @JsonProperty("description") @ExcludeMissing fun _description() = description
+    @JsonProperty("description") @ExcludeMissing fun _description(): JsonField<String> = description
 
     /**
      * The new value of the customer's balance prior to the transaction, in the customer's currency.
      */
-    @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+    @JsonProperty("ending_balance")
+    @ExcludeMissing
+    fun _endingBalance(): JsonField<String> = endingBalance
 
-    @JsonProperty("invoice") @ExcludeMissing fun _invoice() = invoice
+    @JsonProperty("invoice") @ExcludeMissing fun _invoice(): JsonField<Invoice> = invoice
 
     /**
      * The original value of the customer's balance prior to the transaction, in the customer's
      * currency.
      */
-    @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+    @JsonProperty("starting_balance")
+    @ExcludeMissing
+    fun _startingBalance(): JsonField<String> = startingBalance
 
-    @JsonProperty("type") @ExcludeMissing fun _type() = type
+    @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -147,16 +155,16 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var action: JsonField<Action> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var creditNote: JsonField<CreditNote> = JsonMissing.of()
-        private var description: JsonField<String> = JsonMissing.of()
-        private var endingBalance: JsonField<String> = JsonMissing.of()
-        private var invoice: JsonField<Invoice> = JsonMissing.of()
-        private var startingBalance: JsonField<String> = JsonMissing.of()
-        private var type: JsonField<Type> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var action: JsonField<Action>? = null
+        private var amount: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var creditNote: JsonField<CreditNote>? = null
+        private var description: JsonField<String>? = null
+        private var endingBalance: JsonField<String>? = null
+        private var invoice: JsonField<Invoice>? = null
+        private var startingBalance: JsonField<String>? = null
+        private var type: JsonField<Type>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -199,12 +207,17 @@ private constructor(
         /** The creation time of this transaction. */
         fun createdAt(createdAt: JsonField<OffsetDateTime>) = apply { this.createdAt = createdAt }
 
-        fun creditNote(creditNote: CreditNote) = creditNote(JsonField.of(creditNote))
+        fun creditNote(creditNote: CreditNote?) = creditNote(JsonField.ofNullable(creditNote))
+
+        fun creditNote(creditNote: Optional<CreditNote>) = creditNote(creditNote.orElse(null))
 
         fun creditNote(creditNote: JsonField<CreditNote>) = apply { this.creditNote = creditNote }
 
         /** An optional description provided for manual customer balance adjustments. */
-        fun description(description: String) = description(JsonField.of(description))
+        fun description(description: String?) = description(JsonField.ofNullable(description))
+
+        /** An optional description provided for manual customer balance adjustments. */
+        fun description(description: Optional<String>) = description(description.orElse(null))
 
         /** An optional description provided for manual customer balance adjustments. */
         fun description(description: JsonField<String>) = apply { this.description = description }
@@ -223,7 +236,9 @@ private constructor(
             this.endingBalance = endingBalance
         }
 
-        fun invoice(invoice: Invoice) = invoice(JsonField.of(invoice))
+        fun invoice(invoice: Invoice?) = invoice(JsonField.ofNullable(invoice))
+
+        fun invoice(invoice: Optional<Invoice>) = invoice(invoice.orElse(null))
 
         fun invoice(invoice: JsonField<Invoice>) = apply { this.invoice = invoice }
 
@@ -267,16 +282,16 @@ private constructor(
 
         fun build(): CustomerBalanceTransactionListResponse =
             CustomerBalanceTransactionListResponse(
-                id,
-                action,
-                amount,
-                createdAt,
-                creditNote,
-                description,
-                endingBalance,
-                invoice,
-                startingBalance,
-                type,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(action) { "`action` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(creditNote) { "`creditNote` is required but was not set" },
+                checkNotNull(description) { "`description` is required but was not set" },
+                checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                checkNotNull(invoice) { "`invoice` is required but was not set" },
+                checkNotNull(startingBalance) { "`startingBalance` is required but was not set" },
+                checkNotNull(type) { "`type` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -387,7 +402,7 @@ private constructor(
         fun id(): String = id.getRequired("id")
 
         /** The id of the Credit note */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -411,7 +426,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -445,7 +460,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): CreditNote = CreditNote(id, additionalProperties.toImmutable())
+            fun build(): CreditNote =
+                CreditNote(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
@@ -478,7 +497,7 @@ private constructor(
         fun id(): String = id.getRequired("id")
 
         /** The Invoice id */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -502,7 +521,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -536,7 +555,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Invoice = Invoice(id, additionalProperties.toImmutable())
+            fun build(): Invoice =
+                Invoice(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdParams.kt
index 8e72a504..d5bf64e2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdParams.kt
@@ -14,6 +14,114 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to fetch a day-by-day snapshot of a customer's costs in Orb, calculated by
+ * applying pricing information to the underlying usage (see the
+ * [subscription usage endpoint](fetch-subscription-usage.api.mdx) to fetch usage per metric, in
+ * usage units rather than a currency).
+ *
+ * This endpoint can be leveraged for internal tooling and to provide a more transparent billing
+ * experience for your end users:
+ * 1. Understand the cost breakdown per line item historically and in real-time for the current
+ *    billing period.
+ * 2. Provide customer visibility into how different services are contributing to the overall
+ *    invoice with a per-day timeseries (as compared to the
+ *    [upcoming invoice](fetch-upcoming-invoice) resource, which represents a snapshot for the
+ *    current period).
+ * 3. Assess how minimums and discounts affect your customers by teasing apart costs directly as a
+ *    result of usage, as opposed to minimums and discounts at the plan and price level.
+ * 4. Gain insight into key customer health metrics, such as the percent utilization of the minimum
+ *    committed spend.
+ *
+ * ## Fetching subscriptions
+ *
+ * By default, this endpoint fetches the currently active subscription for the customer, and returns
+ * cost information for the subscription's current billing period, broken down by each participating
+ * price. If there are no currently active subscriptions, this will instead default to the most
+ * recently active subscription or return an empty series if none are found. For example, if your
+ * plan charges for compute hours, job runs, and data syncs, then this endpoint would provide a
+ * daily breakdown of your customer's cost for each of those axes.
+ *
+ * If timeframe bounds are specified, Orb fetches all subscriptions that were active in that
+ * timeframe. If two subscriptions overlap on a single day, costs from each price will be summed,
+ * and prices for both subscriptions will be included in the breakdown.
+ *
+ * ## Prepaid plans
+ *
+ * For plans that include prices which deduct credits rather than accrue in-arrears charges in a
+ * billable currency, this endpoint will return the total deduction amount, in credits, for the
+ * specified timeframe.
+ *
+ * ## Cumulative subtotals and totals
+ *
+ * Since the subtotal and total must factor in any billing-period level discounts and minimums, it's
+ * most meaningful to consider costs relative to the start of the subscription's billing period. As
+ * a result, by default this endpoint returns cumulative totals since the beginning of the billing
+ * period. In particular, the `timeframe_start` of a returned timeframe window is _always_ the
+ * beginning of the billing period and `timeframe_end` is incremented one day at a time to build the
+ * result.
+ *
+ * A customer that uses a few API calls a day but has a minimum commitment might exhibit the
+ * following pattern for their subtotal and total in the first few days of the month. Here, we
+ * assume that each API call is $2.50, the customer's plan has a monthly minimum of $50 for this
+ * price, and that the subscription's billing period bounds are aligned to the first of the month:
+ *
+ * | timeframe_start | timeframe_end | Cumulative usage | Subtotal | Total (incl. commitment) |
+ * |-----------------|---------------|------------------|----------|--------------------------|
+ * | 2023-02-01      | 2023-02-02    | 9                | $22.50   | $50.00                   |
+ * | 2023-02-01      | 2023-02-03    | 19               | $47.50   | $50.00                   |
+ * | 2023-02-01      | 2023-02-04    | 20               | $50.00   | $50.00                   |
+ * | 2023-02-01      | 2023-02-05    | 28               | $70.00   | $70.00                   |
+ * | 2023-02-01      | 2023-02-06    | 36               | $90.00   | $90.00                   |
+ *
+ * ### Periodic values
+ *
+ * When the query parameter `view_mode=periodic` is specified, Orb will return an incremental
+ * day-by-day view of costs. In this case, there will always be a one-day difference between
+ * `timeframe_start` and `timeframe_end` for the timeframes returned. This is a transform on top of
+ * the cumulative costs, calculated by taking the difference of each timeframe with the last. Note
+ * that in the above example, the `Total` value would be 0 for the second two data points, since the
+ * minimum commitment has not yet been hit and each day is not contributing anything to the total
+ * cost.
+ *
+ * ## Timeframe bounds
+ *
+ * For an active subscription, both timeframes should be specified in the request. If a subscription
+ * starts or ends within the timeframe, the response will only include windows where the
+ * subscription is active. If a subscription has ended, no timeframe bounds need to be specified and
+ * the response will default to the billing period when the subscription was last active.
+ *
+ * As noted above, `timeframe_start` for a given cumulative datapoint is always the beginning of the
+ * billing period, and `timeframe_end` is incremented one day at a time to construct the response.
+ * When a timeframe is passed in that is not aligned to the current subscription's billing period,
+ * the response will contain cumulative totals from multiple billing periods.
+ *
+ * Suppose the queried customer has a subscription aligned to the 15th of every month. If this
+ * endpoint is queried with the date range `2023-06-01` - `2023-07-01`, the first data point will
+ * represent about half a billing period's worth of costs, accounting for accruals from the start of
+ * the billing period and inclusive of the first day of the timeframe (`timeframe_start = 2023-05-15
+ * 00:00:00`, `timeframe_end = 2023-06-02 00:00:00`)
+ *
+ * | datapoint index | timeframe_start | timeframe_end |
+ * |-----------------|-----------------|---------------|
+ * | 0               | 2023-05-15      | 2023-06-02    |
+ * | 1               | 2023-05-15      | 2023-06-03    |
+ * | 2               | ...             | ...           |
+ * | 3               | 2023-05-15      | 2023-06-14    |
+ * | 4               | 2023-06-15      | 2023-06-16    |
+ * | 5               | 2023-06-15      | 2023-06-17    |
+ * | 6               | ...             | ...           |
+ * | 7               | 2023-06-15      | 2023-07-01    |
+ *
+ * You can see this sliced timeframe visualized [here](https://i.imgur.com/TXhYgme.png).
+ *
+ * ### Matrix prices
+ *
+ * When a price uses matrix pricing, it's important to view costs grouped by those matrix
+ * dimensions. Orb will return `price_groups` with the `grouping_key` and `secondary_grouping_key`
+ * based on the matrix price definition, for each `grouping_value` and `secondary_grouping_value`
+ * available.
+ */
 class CustomerCostListByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdResponse.kt
index ef215cf0..ed4307e0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListByExternalIdResponse.kt
@@ -29,7 +29,7 @@ private constructor(
 
     fun data(): List<Data> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,21 +53,36 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Data>> = JsonMissing.of()
+        private var data: JsonField<MutableList<Data>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(
             customerCostListByExternalIdResponse: CustomerCostListByExternalIdResponse
         ) = apply {
-            data = customerCostListByExternalIdResponse.data
+            data = customerCostListByExternalIdResponse.data.map { it.toMutableList() }
             additionalProperties =
                 customerCostListByExternalIdResponse.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Data>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Data>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Data) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -90,7 +105,8 @@ private constructor(
 
         fun build(): CustomerCostListByExternalIdResponse =
             CustomerCostListByExternalIdResponse(
-                data.map { it.toImmutable() },
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
                 additionalProperties.toImmutable()
             )
     }
@@ -130,17 +146,23 @@ private constructor(
         /** Total costs for the timeframe, including any minimums and discounts. */
         fun total(): String = total.getRequired("total")
 
-        @JsonProperty("per_price_costs") @ExcludeMissing fun _perPriceCosts() = perPriceCosts
+        @JsonProperty("per_price_costs")
+        @ExcludeMissing
+        fun _perPriceCosts(): JsonField<List<PerPriceCost>> = perPriceCosts
 
         /** Total costs for the timeframe, excluding any minimums and discounts. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
-        @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-        @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         /** Total costs for the timeframe, including any minimums and discounts. */
-        @JsonProperty("total") @ExcludeMissing fun _total() = total
+        @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -168,16 +190,16 @@ private constructor(
 
         class Builder {
 
-            private var perPriceCosts: JsonField<List<PerPriceCost>> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var total: JsonField<String> = JsonMissing.of()
+            private var perPriceCosts: JsonField<MutableList<PerPriceCost>>? = null
+            private var subtotal: JsonField<String>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
+            private var total: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(data: Data) = apply {
-                perPriceCosts = data.perPriceCosts
+                perPriceCosts = data.perPriceCosts.map { it.toMutableList() }
                 subtotal = data.subtotal
                 timeframeEnd = data.timeframeEnd
                 timeframeStart = data.timeframeStart
@@ -189,7 +211,20 @@ private constructor(
                 perPriceCosts(JsonField.of(perPriceCosts))
 
             fun perPriceCosts(perPriceCosts: JsonField<List<PerPriceCost>>) = apply {
-                this.perPriceCosts = perPriceCosts
+                this.perPriceCosts = perPriceCosts.map { it.toMutableList() }
+            }
+
+            fun addPerPriceCost(perPriceCost: PerPriceCost) = apply {
+                perPriceCosts =
+                    (perPriceCosts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(perPriceCost)
+                    }
             }
 
             /** Total costs for the timeframe, excluding any minimums and discounts. */
@@ -239,11 +274,12 @@ private constructor(
 
             fun build(): Data =
                 Data(
-                    perPriceCosts.map { it.toImmutable() },
-                    subtotal,
-                    timeframeEnd,
-                    timeframeStart,
-                    total,
+                    checkNotNull(perPriceCosts) { "`perPriceCosts` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                    checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
+                    checkNotNull(total) { "`total` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -735,16 +771,16 @@ private constructor(
              * }
              * ```
              */
-            @JsonProperty("price") @ExcludeMissing fun _price() = price
+            @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
             /** Price's contributions for the timeframe, excluding any minimums and discounts. */
-            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
             /** Price's contributions for the timeframe, including minimums and discounts. */
-            @JsonProperty("total") @ExcludeMissing fun _total() = total
+            @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
             /** The price's quantity for the timeframe */
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -771,9 +807,9 @@ private constructor(
 
             class Builder {
 
-                private var price: JsonField<Price> = JsonMissing.of()
-                private var subtotal: JsonField<String> = JsonMissing.of()
-                private var total: JsonField<String> = JsonMissing.of()
+                private var price: JsonField<Price>? = null
+                private var subtotal: JsonField<String>? = null
+                private var total: JsonField<String>? = null
                 private var quantity: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -1254,6 +1290,73 @@ private constructor(
                  */
                 fun price(price: JsonField<Price>) = apply { this.price = price }
 
+                fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+                fun price(packagePrice: Price.PackagePrice) =
+                    price(Price.ofPackagePrice(packagePrice))
+
+                fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+                fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+                fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                    price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+                fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+                fun price(bulkBpsPrice: Price.BulkBpsPrice) =
+                    price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+                fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+                fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                    price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+                fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                    price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+                fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                    price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+                fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                    price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+                fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                    price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+                fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                    price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+                fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                    price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+                fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                    price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+                fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                    price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+                fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                    price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+                fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                    price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+                fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                    price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+                fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                    price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+                fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                    price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+                fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                    price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+                fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                    price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
                 /**
                  * Price's contributions for the timeframe, excluding any minimums and discounts.
                  */
@@ -1271,7 +1374,15 @@ private constructor(
                 fun total(total: JsonField<String>) = apply { this.total = total }
 
                 /** The price's quantity for the timeframe */
-                fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
+                fun quantity(quantity: Double?) = quantity(JsonField.ofNullable(quantity))
+
+                /** The price's quantity for the timeframe */
+                fun quantity(quantity: Double) = quantity(quantity as Double?)
+
+                /** The price's quantity for the timeframe */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun quantity(quantity: Optional<Double>) =
+                    quantity(quantity.orElse(null) as Double?)
 
                 /** The price's quantity for the timeframe */
                 fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -1300,9 +1411,9 @@ private constructor(
 
                 fun build(): PerPriceCost =
                     PerPriceCost(
-                        price,
-                        subtotal,
-                        total,
+                        checkNotNull(price) { "`price` is required but was not set" },
+                        checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                        checkNotNull(total) { "`total` is required but was not set" },
                         quantity,
                         additionalProperties.toImmutable(),
                     )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListParams.kt
index 3a06cae2..a6e7a627 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListParams.kt
@@ -14,6 +14,114 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to fetch a day-by-day snapshot of a customer's costs in Orb, calculated by
+ * applying pricing information to the underlying usage (see the
+ * [subscription usage endpoint](fetch-subscription-usage.api.mdx) to fetch usage per metric, in
+ * usage units rather than a currency).
+ *
+ * This endpoint can be leveraged for internal tooling and to provide a more transparent billing
+ * experience for your end users:
+ * 1. Understand the cost breakdown per line item historically and in real-time for the current
+ *    billing period.
+ * 2. Provide customer visibility into how different services are contributing to the overall
+ *    invoice with a per-day timeseries (as compared to the
+ *    [upcoming invoice](fetch-upcoming-invoice) resource, which represents a snapshot for the
+ *    current period).
+ * 3. Assess how minimums and discounts affect your customers by teasing apart costs directly as a
+ *    result of usage, as opposed to minimums and discounts at the plan and price level.
+ * 4. Gain insight into key customer health metrics, such as the percent utilization of the minimum
+ *    committed spend.
+ *
+ * ## Fetching subscriptions
+ *
+ * By default, this endpoint fetches the currently active subscription for the customer, and returns
+ * cost information for the subscription's current billing period, broken down by each participating
+ * price. If there are no currently active subscriptions, this will instead default to the most
+ * recently active subscription or return an empty series if none are found. For example, if your
+ * plan charges for compute hours, job runs, and data syncs, then this endpoint would provide a
+ * daily breakdown of your customer's cost for each of those axes.
+ *
+ * If timeframe bounds are specified, Orb fetches all subscriptions that were active in that
+ * timeframe. If two subscriptions overlap on a single day, costs from each price will be summed,
+ * and prices for both subscriptions will be included in the breakdown.
+ *
+ * ## Prepaid plans
+ *
+ * For plans that include prices which deduct credits rather than accrue in-arrears charges in a
+ * billable currency, this endpoint will return the total deduction amount, in credits, for the
+ * specified timeframe.
+ *
+ * ## Cumulative subtotals and totals
+ *
+ * Since the subtotal and total must factor in any billing-period level discounts and minimums, it's
+ * most meaningful to consider costs relative to the start of the subscription's billing period. As
+ * a result, by default this endpoint returns cumulative totals since the beginning of the billing
+ * period. In particular, the `timeframe_start` of a returned timeframe window is _always_ the
+ * beginning of the billing period and `timeframe_end` is incremented one day at a time to build the
+ * result.
+ *
+ * A customer that uses a few API calls a day but has a minimum commitment might exhibit the
+ * following pattern for their subtotal and total in the first few days of the month. Here, we
+ * assume that each API call is $2.50, the customer's plan has a monthly minimum of $50 for this
+ * price, and that the subscription's billing period bounds are aligned to the first of the month:
+ *
+ * | timeframe_start | timeframe_end | Cumulative usage | Subtotal | Total (incl. commitment) |
+ * |-----------------|---------------|------------------|----------|--------------------------|
+ * | 2023-02-01      | 2023-02-02    | 9                | $22.50   | $50.00                   |
+ * | 2023-02-01      | 2023-02-03    | 19               | $47.50   | $50.00                   |
+ * | 2023-02-01      | 2023-02-04    | 20               | $50.00   | $50.00                   |
+ * | 2023-02-01      | 2023-02-05    | 28               | $70.00   | $70.00                   |
+ * | 2023-02-01      | 2023-02-06    | 36               | $90.00   | $90.00                   |
+ *
+ * ### Periodic values
+ *
+ * When the query parameter `view_mode=periodic` is specified, Orb will return an incremental
+ * day-by-day view of costs. In this case, there will always be a one-day difference between
+ * `timeframe_start` and `timeframe_end` for the timeframes returned. This is a transform on top of
+ * the cumulative costs, calculated by taking the difference of each timeframe with the last. Note
+ * that in the above example, the `Total` value would be 0 for the second two data points, since the
+ * minimum commitment has not yet been hit and each day is not contributing anything to the total
+ * cost.
+ *
+ * ## Timeframe bounds
+ *
+ * For an active subscription, both timeframes should be specified in the request. If a subscription
+ * starts or ends within the timeframe, the response will only include windows where the
+ * subscription is active. If a subscription has ended, no timeframe bounds need to be specified and
+ * the response will default to the billing period when the subscription was last active.
+ *
+ * As noted above, `timeframe_start` for a given cumulative datapoint is always the beginning of the
+ * billing period, and `timeframe_end` is incremented one day at a time to construct the response.
+ * When a timeframe is passed in that is not aligned to the current subscription's billing period,
+ * the response will contain cumulative totals from multiple billing periods.
+ *
+ * Suppose the queried customer has a subscription aligned to the 15th of every month. If this
+ * endpoint is queried with the date range `2023-06-01` - `2023-07-01`, the first data point will
+ * represent about half a billing period's worth of costs, accounting for accruals from the start of
+ * the billing period and inclusive of the first day of the timeframe (`timeframe_start = 2023-05-15
+ * 00:00:00`, `timeframe_end = 2023-06-02 00:00:00`)
+ *
+ * | datapoint index | timeframe_start | timeframe_end |
+ * |-----------------|-----------------|---------------|
+ * | 0               | 2023-05-15      | 2023-06-02    |
+ * | 1               | 2023-05-15      | 2023-06-03    |
+ * | 2               | ...             | ...           |
+ * | 3               | 2023-05-15      | 2023-06-14    |
+ * | 4               | 2023-06-15      | 2023-06-16    |
+ * | 5               | 2023-06-15      | 2023-06-17    |
+ * | 6               | ...             | ...           |
+ * | 7               | 2023-06-15      | 2023-07-01    |
+ *
+ * You can see this sliced timeframe visualized [here](https://i.imgur.com/TXhYgme.png).
+ *
+ * ### Matrix prices
+ *
+ * When a price uses matrix pricing, it's important to view costs grouped by those matrix
+ * dimensions. Orb will return `price_groups` with the `grouping_key` and `secondary_grouping_key`
+ * based on the matrix price definition, for each `grouping_value` and `secondary_grouping_value`
+ * available.
+ */
 class CustomerCostListParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListResponse.kt
index 7e284d2f..4052e29a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCostListResponse.kt
@@ -29,7 +29,7 @@ private constructor(
 
     fun data(): List<Data> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,18 +53,33 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Data>> = JsonMissing.of()
+        private var data: JsonField<MutableList<Data>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(customerCostListResponse: CustomerCostListResponse) = apply {
-            data = customerCostListResponse.data
+            data = customerCostListResponse.data.map { it.toMutableList() }
             additionalProperties = customerCostListResponse.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Data>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Data>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Data) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -87,7 +102,8 @@ private constructor(
 
         fun build(): CustomerCostListResponse =
             CustomerCostListResponse(
-                data.map { it.toImmutable() },
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
                 additionalProperties.toImmutable()
             )
     }
@@ -127,17 +143,23 @@ private constructor(
         /** Total costs for the timeframe, including any minimums and discounts. */
         fun total(): String = total.getRequired("total")
 
-        @JsonProperty("per_price_costs") @ExcludeMissing fun _perPriceCosts() = perPriceCosts
+        @JsonProperty("per_price_costs")
+        @ExcludeMissing
+        fun _perPriceCosts(): JsonField<List<PerPriceCost>> = perPriceCosts
 
         /** Total costs for the timeframe, excluding any minimums and discounts. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
-        @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-        @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         /** Total costs for the timeframe, including any minimums and discounts. */
-        @JsonProperty("total") @ExcludeMissing fun _total() = total
+        @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -165,16 +187,16 @@ private constructor(
 
         class Builder {
 
-            private var perPriceCosts: JsonField<List<PerPriceCost>> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var total: JsonField<String> = JsonMissing.of()
+            private var perPriceCosts: JsonField<MutableList<PerPriceCost>>? = null
+            private var subtotal: JsonField<String>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
+            private var total: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(data: Data) = apply {
-                perPriceCosts = data.perPriceCosts
+                perPriceCosts = data.perPriceCosts.map { it.toMutableList() }
                 subtotal = data.subtotal
                 timeframeEnd = data.timeframeEnd
                 timeframeStart = data.timeframeStart
@@ -186,7 +208,20 @@ private constructor(
                 perPriceCosts(JsonField.of(perPriceCosts))
 
             fun perPriceCosts(perPriceCosts: JsonField<List<PerPriceCost>>) = apply {
-                this.perPriceCosts = perPriceCosts
+                this.perPriceCosts = perPriceCosts.map { it.toMutableList() }
+            }
+
+            fun addPerPriceCost(perPriceCost: PerPriceCost) = apply {
+                perPriceCosts =
+                    (perPriceCosts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(perPriceCost)
+                    }
             }
 
             /** Total costs for the timeframe, excluding any minimums and discounts. */
@@ -236,11 +271,12 @@ private constructor(
 
             fun build(): Data =
                 Data(
-                    perPriceCosts.map { it.toImmutable() },
-                    subtotal,
-                    timeframeEnd,
-                    timeframeStart,
-                    total,
+                    checkNotNull(perPriceCosts) { "`perPriceCosts` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                    checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
+                    checkNotNull(total) { "`total` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -732,16 +768,16 @@ private constructor(
              * }
              * ```
              */
-            @JsonProperty("price") @ExcludeMissing fun _price() = price
+            @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
             /** Price's contributions for the timeframe, excluding any minimums and discounts. */
-            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
             /** Price's contributions for the timeframe, including minimums and discounts. */
-            @JsonProperty("total") @ExcludeMissing fun _total() = total
+            @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
             /** The price's quantity for the timeframe */
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -768,9 +804,9 @@ private constructor(
 
             class Builder {
 
-                private var price: JsonField<Price> = JsonMissing.of()
-                private var subtotal: JsonField<String> = JsonMissing.of()
-                private var total: JsonField<String> = JsonMissing.of()
+                private var price: JsonField<Price>? = null
+                private var subtotal: JsonField<String>? = null
+                private var total: JsonField<String>? = null
                 private var quantity: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -1251,6 +1287,73 @@ private constructor(
                  */
                 fun price(price: JsonField<Price>) = apply { this.price = price }
 
+                fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+                fun price(packagePrice: Price.PackagePrice) =
+                    price(Price.ofPackagePrice(packagePrice))
+
+                fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+                fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+                fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                    price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+                fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+                fun price(bulkBpsPrice: Price.BulkBpsPrice) =
+                    price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+                fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+                fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                    price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+                fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                    price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+                fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                    price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+                fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                    price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+                fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                    price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+                fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                    price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+                fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                    price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+                fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                    price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+                fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                    price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+                fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                    price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+                fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                    price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+                fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                    price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+                fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                    price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+                fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                    price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+                fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                    price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+                fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                    price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
                 /**
                  * Price's contributions for the timeframe, excluding any minimums and discounts.
                  */
@@ -1268,7 +1371,15 @@ private constructor(
                 fun total(total: JsonField<String>) = apply { this.total = total }
 
                 /** The price's quantity for the timeframe */
-                fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
+                fun quantity(quantity: Double?) = quantity(JsonField.ofNullable(quantity))
+
+                /** The price's quantity for the timeframe */
+                fun quantity(quantity: Double) = quantity(quantity as Double?)
+
+                /** The price's quantity for the timeframe */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun quantity(quantity: Optional<Double>) =
+                    quantity(quantity.orElse(null) as Double?)
 
                 /** The price's quantity for the timeframe */
                 fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -1297,9 +1408,9 @@ private constructor(
 
                 fun build(): PerPriceCost =
                     PerPriceCost(
-                        price,
-                        subtotal,
-                        total,
+                        checkNotNull(price) { "`price` is required but was not set" },
+                        checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                        checkNotNull(total) { "`total` is required but was not set" },
                         quantity,
                         additionalProperties.toImmutable(),
                     )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreateParams.kt
index b119dfab..9eab1a6f 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,18 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This operation is used to create an Orb customer, who is party to the core billing relationship.
+ * See [Customer](../guides/concepts#customer) for an overview of the customer resource.
+ *
+ * This endpoint is critical in the following Orb functionality:
+ * - Automated charges can be configured by setting `payment_provider` and `payment_provider_id` to
+ *   automatically issue invoices
+ * - [Customer ID Aliases](../guides/events-and-metrics/customer-aliases) can be configured by
+ *   setting `external_customer_id`
+ * - [Timezone localization](../guides/product-catalog/timezones.md) can be configured on a
+ *   per-customer basis by setting the `timezone` parameter
+ */
 class CustomerCreateParams
 constructor(
     private val body: CustomerCreateBody,
@@ -219,64 +232,476 @@ constructor(
      */
     fun timezone(): Optional<String> = body.timezone()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * A valid customer email, to be used for notifications. When Orb triggers payment through a
+     * payment gateway, this email will be used for any automatically issued receipts.
+     */
+    fun _email(): JsonField<String> = body._email()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The full name of the customer */
+    fun _name(): JsonField<String> = body._name()
+
+    fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+        body._accountingSyncConfiguration()
+
+    /**
+     * Additional email addresses for this customer. If populated, these email addresses will be
+     * CC'd for customer communications.
+     */
+    fun _additionalEmails(): JsonField<List<String>> = body._additionalEmails()
+
+    /**
+     * Used to determine if invoices for this customer will automatically attempt to charge a saved
+     * payment method, if available. This parameter defaults to `True` when a payment provider is
+     * provided on customer creation.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
+
+    fun _billingAddress(): JsonField<BillingAddress> = body._billingAddress()
+
+    /**
+     * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+     * creation time, will be set at subscription creation time.
+     */
+    fun _currency(): JsonField<String> = body._currency()
+
+    fun _emailDelivery(): JsonField<Boolean> = body._emailDelivery()
+
+    /**
+     * An optional user-defined ID for this customer resource, used throughout the system as an
+     * alias for this Customer. Use this field to identify a customer by an existing identifier in
+     * your system.
+     */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /**
+     * This is used for creating charges or invoices in an external system via Orb. When not in test
+     * mode, the connection must first be configured in the Orb webapp.
+     */
+    fun _paymentProvider(): JsonField<PaymentProvider> = body._paymentProvider()
+
+    /**
+     * The ID of this customer in an external payments solution, such as Stripe. This is used for
+     * creating charges or invoices in the external system via Orb.
+     */
+    fun _paymentProviderId(): JsonField<String> = body._paymentProviderId()
+
+    fun _reportingConfiguration(): JsonField<ReportingConfiguration> =
+        body._reportingConfiguration()
+
+    fun _shippingAddress(): JsonField<ShippingAddress> = body._shippingAddress()
+
+    fun _taxConfiguration(): JsonField<TaxConfiguration> = body._taxConfiguration()
+
+    /**
+     * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
+     * headers of invoices.
+     *
+     * ### Supported Tax ID Countries and Types
+     * |Country             |Type        |Description                                                                                            |
+     * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+     * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+     * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+     * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+     * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+     * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+     * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+     * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+     * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+     * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+     * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+     * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+     * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+     * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+     * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+     * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+     * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+     * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+     * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+     * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+     * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+     * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+     * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+     * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+     * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+     * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+     * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |France              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+     * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+     * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+     * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+     * |India               |`in_gst`    |Indian GST Number                                                                                      |
+     * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+     * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+     * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+     * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+     * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+     * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+     * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+     * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+     * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+     * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+     * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+     * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+     * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+     * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+     * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+     * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+     * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+     * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+     * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+     * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+     * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+     * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+     * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+     * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+     * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+     * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+     * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+     * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+     * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+     * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+     * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+     * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+     * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+     * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+     * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+     * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+     * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+     * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+     * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+     * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+     * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+     * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+     * |United States       |`us_ein`    |United States EIN                                                                                      |
+     * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+     * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+     * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+     */
+    fun _taxId(): JsonField<TaxId> = body._taxId()
+
+    /**
+     * A timezone identifier from the IANA timezone database, such as `"America/Los_Angeles"`. This
+     * defaults to your account's timezone if not set. This cannot be changed after customer
+     * creation.
+     */
+    fun _timezone(): JsonField<String> = body._timezone()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
 
     @JvmSynthetic internal fun getQueryParams(): QueryParams = additionalQueryParams
 
-    @NoAutoDetect
-    class CustomerCreateBody
-    @JsonCreator
-    internal constructor(
-        @JsonProperty("email") private val email: String,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("accounting_sync_configuration")
-        private val accountingSyncConfiguration: AccountingSyncConfiguration?,
-        @JsonProperty("additional_emails") private val additionalEmails: List<String>?,
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
-        @JsonProperty("billing_address") private val billingAddress: BillingAddress?,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("email_delivery") private val emailDelivery: Boolean?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("payment_provider") private val paymentProvider: PaymentProvider?,
-        @JsonProperty("payment_provider_id") private val paymentProviderId: String?,
-        @JsonProperty("reporting_configuration")
-        private val reportingConfiguration: ReportingConfiguration?,
-        @JsonProperty("shipping_address") private val shippingAddress: ShippingAddress?,
-        @JsonProperty("tax_configuration") private val taxConfiguration: TaxConfiguration?,
-        @JsonProperty("tax_id") private val taxId: TaxId?,
-        @JsonProperty("timezone") private val timezone: String?,
-        @JsonAnySetter
-        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-    ) {
+    @NoAutoDetect
+    class CustomerCreateBody
+    @JsonCreator
+    internal constructor(
+        @JsonProperty("email")
+        @ExcludeMissing
+        private val email: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("accounting_sync_configuration")
+        @ExcludeMissing
+        private val accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("additional_emails")
+        @ExcludeMissing
+        private val additionalEmails: JsonField<List<String>> = JsonMissing.of(),
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_address")
+        @ExcludeMissing
+        private val billingAddress: JsonField<BillingAddress> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("email_delivery")
+        @ExcludeMissing
+        private val emailDelivery: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("payment_provider")
+        @ExcludeMissing
+        private val paymentProvider: JsonField<PaymentProvider> = JsonMissing.of(),
+        @JsonProperty("payment_provider_id")
+        @ExcludeMissing
+        private val paymentProviderId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("reporting_configuration")
+        @ExcludeMissing
+        private val reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of(),
+        @JsonProperty("shipping_address")
+        @ExcludeMissing
+        private val shippingAddress: JsonField<ShippingAddress> = JsonMissing.of(),
+        @JsonProperty("tax_configuration")
+        @ExcludeMissing
+        private val taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of(),
+        @JsonProperty("tax_id")
+        @ExcludeMissing
+        private val taxId: JsonField<TaxId> = JsonMissing.of(),
+        @JsonProperty("timezone")
+        @ExcludeMissing
+        private val timezone: JsonField<String> = JsonMissing.of(),
+        @JsonAnySetter
+        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+    ) {
+
+        /**
+         * A valid customer email, to be used for notifications. When Orb triggers payment through a
+         * payment gateway, this email will be used for any automatically issued receipts.
+         */
+        fun email(): String = email.getRequired("email")
+
+        /** The full name of the customer */
+        fun name(): String = name.getRequired("name")
+
+        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
+            Optional.ofNullable(
+                accountingSyncConfiguration.getNullable("accounting_sync_configuration")
+            )
+
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(): Optional<List<String>> =
+            Optional.ofNullable(additionalEmails.getNullable("additional_emails"))
+
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        fun billingAddress(): Optional<BillingAddress> =
+            Optional.ofNullable(billingAddress.getNullable("billing_address"))
+
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        fun emailDelivery(): Optional<Boolean> =
+            Optional.ofNullable(emailDelivery.getNullable("email_delivery"))
+
+        /**
+         * An optional user-defined ID for this customer resource, used throughout the system as an
+         * alias for this Customer. Use this field to identify a customer by an existing identifier
+         * in your system.
+         */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode, the connection must first be configured in the Orb webapp.
+         */
+        fun paymentProvider(): Optional<PaymentProvider> =
+            Optional.ofNullable(paymentProvider.getNullable("payment_provider"))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(): Optional<String> =
+            Optional.ofNullable(paymentProviderId.getNullable("payment_provider_id"))
+
+        fun reportingConfiguration(): Optional<ReportingConfiguration> =
+            Optional.ofNullable(reportingConfiguration.getNullable("reporting_configuration"))
+
+        fun shippingAddress(): Optional<ShippingAddress> =
+            Optional.ofNullable(shippingAddress.getNullable("shipping_address"))
+
+        fun taxConfiguration(): Optional<TaxConfiguration> =
+            Optional.ofNullable(taxConfiguration.getNullable("tax_configuration"))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId.getNullable("tax_id"))
+
+        /**
+         * A timezone identifier from the IANA timezone database, such as `"America/Los_Angeles"`.
+         * This defaults to your account's timezone if not set. This cannot be changed after
+         * customer creation.
+         */
+        fun timezone(): Optional<String> = Optional.ofNullable(timezone.getNullable("timezone"))
 
         /**
          * A valid customer email, to be used for notifications. When Orb triggers payment through a
          * payment gateway, this email will be used for any automatically issued receipts.
          */
-        @JsonProperty("email") fun email(): String = email
+        @JsonProperty("email") @ExcludeMissing fun _email(): JsonField<String> = email
 
         /** The full name of the customer */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("accounting_sync_configuration")
-        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
-            Optional.ofNullable(accountingSyncConfiguration)
+        @ExcludeMissing
+        fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+            accountingSyncConfiguration
 
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
          */
         @JsonProperty("additional_emails")
-        fun additionalEmails(): Optional<List<String>> = Optional.ofNullable(additionalEmails)
+        @ExcludeMissing
+        fun _additionalEmails(): JsonField<List<String>> = additionalEmails
 
         /**
          * Used to determine if invoices for this customer will automatically attempt to charge a
@@ -284,19 +709,22 @@ constructor(
          * provider is provided on customer creation.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         @JsonProperty("billing_address")
-        fun billingAddress(): Optional<BillingAddress> = Optional.ofNullable(billingAddress)
+        @ExcludeMissing
+        fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         @JsonProperty("email_delivery")
-        fun emailDelivery(): Optional<Boolean> = Optional.ofNullable(emailDelivery)
+        @ExcludeMissing
+        fun _emailDelivery(): JsonField<Boolean> = emailDelivery
 
         /**
          * An optional user-defined ID for this customer resource, used throughout the system as an
@@ -304,38 +732,43 @@ constructor(
          * in your system.
          */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
          * test mode, the connection must first be configured in the Orb webapp.
          */
         @JsonProperty("payment_provider")
-        fun paymentProvider(): Optional<PaymentProvider> = Optional.ofNullable(paymentProvider)
+        @ExcludeMissing
+        fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
         @JsonProperty("payment_provider_id")
-        fun paymentProviderId(): Optional<String> = Optional.ofNullable(paymentProviderId)
+        @ExcludeMissing
+        fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
         @JsonProperty("reporting_configuration")
-        fun reportingConfiguration(): Optional<ReportingConfiguration> =
-            Optional.ofNullable(reportingConfiguration)
+        @ExcludeMissing
+        fun _reportingConfiguration(): JsonField<ReportingConfiguration> = reportingConfiguration
 
         @JsonProperty("shipping_address")
-        fun shippingAddress(): Optional<ShippingAddress> = Optional.ofNullable(shippingAddress)
+        @ExcludeMissing
+        fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
         @JsonProperty("tax_configuration")
-        fun taxConfiguration(): Optional<TaxConfiguration> = Optional.ofNullable(taxConfiguration)
+        @ExcludeMissing
+        fun _taxConfiguration(): JsonField<TaxConfiguration> = taxConfiguration
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -443,19 +876,44 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        @JsonProperty("tax_id") fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId)
+        @JsonProperty("tax_id") @ExcludeMissing fun _taxId(): JsonField<TaxId> = taxId
 
         /**
          * A timezone identifier from the IANA timezone database, such as `"America/Los_Angeles"`.
          * This defaults to your account's timezone if not set. This cannot be changed after
          * customer creation.
          */
-        @JsonProperty("timezone") fun timezone(): Optional<String> = Optional.ofNullable(timezone)
+        @JsonProperty("timezone") @ExcludeMissing fun _timezone(): JsonField<String> = timezone
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerCreateBody = apply {
+            if (!validated) {
+                email()
+                name()
+                accountingSyncConfiguration().map { it.validate() }
+                additionalEmails()
+                autoCollection()
+                billingAddress().map { it.validate() }
+                currency()
+                emailDelivery()
+                externalCustomerId()
+                metadata().map { it.validate() }
+                paymentProvider()
+                paymentProviderId()
+                reportingConfiguration().map { it.validate() }
+                shippingAddress().map { it.validate() }
+                taxConfiguration()
+                taxId().map { it.validate() }
+                timezone()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -465,23 +923,24 @@ constructor(
 
         class Builder {
 
-            private var email: String? = null
-            private var name: String? = null
-            private var accountingSyncConfiguration: AccountingSyncConfiguration? = null
-            private var additionalEmails: MutableList<String>? = null
-            private var autoCollection: Boolean? = null
-            private var billingAddress: BillingAddress? = null
-            private var currency: String? = null
-            private var emailDelivery: Boolean? = null
-            private var externalCustomerId: String? = null
-            private var metadata: Metadata? = null
-            private var paymentProvider: PaymentProvider? = null
-            private var paymentProviderId: String? = null
-            private var reportingConfiguration: ReportingConfiguration? = null
-            private var shippingAddress: ShippingAddress? = null
-            private var taxConfiguration: TaxConfiguration? = null
-            private var taxId: TaxId? = null
-            private var timezone: String? = null
+            private var email: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+                JsonMissing.of()
+            private var additionalEmails: JsonField<MutableList<String>>? = null
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var emailDelivery: JsonField<Boolean> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
+            private var paymentProviderId: JsonField<String> = JsonMissing.of()
+            private var reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of()
+            private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
+            private var taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of()
+            private var taxId: JsonField<TaxId> = JsonMissing.of()
+            private var timezone: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -489,7 +948,7 @@ constructor(
                 email = customerCreateBody.email
                 name = customerCreateBody.name
                 accountingSyncConfiguration = customerCreateBody.accountingSyncConfiguration
-                additionalEmails = customerCreateBody.additionalEmails?.toMutableList()
+                additionalEmails = customerCreateBody.additionalEmails.map { it.toMutableList() }
                 autoCollection = customerCreateBody.autoCollection
                 billingAddress = customerCreateBody.billingAddress
                 currency = customerCreateBody.currency
@@ -511,26 +970,39 @@ constructor(
              * through a payment gateway, this email will be used for any automatically issued
              * receipts.
              */
-            fun email(email: String) = apply { this.email = email }
+            fun email(email: String) = email(JsonField.of(email))
+
+            /**
+             * A valid customer email, to be used for notifications. When Orb triggers payment
+             * through a payment gateway, this email will be used for any automatically issued
+             * receipts.
+             */
+            fun email(email: JsonField<String>) = apply { this.email = email }
+
+            /** The full name of the customer */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The full name of the customer */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: AccountingSyncConfiguration?
-            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+            ) = accountingSyncConfiguration(JsonField.ofNullable(accountingSyncConfiguration))
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
             ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+            fun accountingSyncConfiguration(
+                accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
-            fun additionalEmails(additionalEmails: List<String>?) = apply {
-                this.additionalEmails = additionalEmails?.toMutableList()
-            }
+            fun additionalEmails(additionalEmails: List<String>?) =
+                additionalEmails(JsonField.ofNullable(additionalEmails))
 
             /**
              * Additional email addresses for this customer. If populated, these email addresses
@@ -539,13 +1011,29 @@ constructor(
             fun additionalEmails(additionalEmails: Optional<List<String>>) =
                 additionalEmails(additionalEmails.orElse(null))
 
+            /**
+             * Additional email addresses for this customer. If populated, these email addresses
+             * will be CC'd for customer communications.
+             */
+            fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+                this.additionalEmails = additionalEmails.map { it.toMutableList() }
+            }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
             fun addAdditionalEmail(additionalEmail: String) = apply {
                 additionalEmails =
-                    (additionalEmails ?: mutableListOf()).apply { add(additionalEmail) }
+                    (additionalEmails ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(additionalEmail)
+                    }
             }
 
             /**
@@ -553,9 +1041,8 @@ constructor(
              * a saved payment method, if available. This parameter defaults to `True` when a
              * payment provider is provided on customer creation.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Used to determine if invoices for this customer will automatically attempt to charge
@@ -573,18 +1060,30 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
-            fun billingAddress(billingAddress: BillingAddress?) = apply {
-                this.billingAddress = billingAddress
+            /**
+             * Used to determine if invoices for this customer will automatically attempt to charge
+             * a saved payment method, if available. This parameter defaults to `True` when a
+             * payment provider is provided on customer creation.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
             }
 
+            fun billingAddress(billingAddress: BillingAddress?) =
+                billingAddress(JsonField.ofNullable(billingAddress))
+
             fun billingAddress(billingAddress: Optional<BillingAddress>) =
                 billingAddress(billingAddress.orElse(null))
 
+            fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+                this.billingAddress = billingAddress
+            }
+
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
              * at creation time, will be set at subscription creation time.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
@@ -592,9 +1091,14 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
-            fun emailDelivery(emailDelivery: Boolean?) = apply {
-                this.emailDelivery = emailDelivery
-            }
+            /**
+             * An ISO 4217 currency string used for the customer's invoices and balance. If not set
+             * at creation time, will be set at subscription creation time.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            fun emailDelivery(emailDelivery: Boolean?) =
+                emailDelivery(JsonField.ofNullable(emailDelivery))
 
             fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
 
@@ -602,14 +1106,17 @@ constructor(
             fun emailDelivery(emailDelivery: Optional<Boolean>) =
                 emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+            fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+                this.emailDelivery = emailDelivery
+            }
+
             /**
              * An optional user-defined ID for this customer resource, used throughout the system as
              * an alias for this Customer. Use this field to identify a customer by an existing
              * identifier in your system.
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * An optional user-defined ID for this customer resource, used throughout the system as
@@ -619,12 +1126,21 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * An optional user-defined ID for this customer resource, used throughout the system as
+             * an alias for this Customer. Use this field to identify a customer by an existing
+             * identifier in your system.
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -633,13 +1149,19 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
              * in test mode, the connection must first be configured in the Orb webapp.
              */
-            fun paymentProvider(paymentProvider: PaymentProvider?) = apply {
-                this.paymentProvider = paymentProvider
-            }
+            fun paymentProvider(paymentProvider: PaymentProvider?) =
+                paymentProvider(JsonField.ofNullable(paymentProvider))
 
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
@@ -648,54 +1170,184 @@ constructor(
             fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
                 paymentProvider(paymentProvider.orElse(null))
 
+            /**
+             * This is used for creating charges or invoices in an external system via Orb. When not
+             * in test mode, the connection must first be configured in the Orb webapp.
+             */
+            fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+                this.paymentProvider = paymentProvider
+            }
+
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: String?) = apply {
-                this.paymentProviderId = paymentProviderId
-            }
+            fun paymentProviderId(paymentProviderId: String?) =
+                paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+            /**
+             * The ID of this customer in an external payments solution, such as Stripe. This is
+             * used for creating charges or invoices in the external system via Orb.
+             */
+            fun paymentProviderId(paymentProviderId: Optional<String>) =
+                paymentProviderId(paymentProviderId.orElse(null))
 
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: Optional<String>) =
-                paymentProviderId(paymentProviderId.orElse(null))
-
-            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-                this.reportingConfiguration = reportingConfiguration
-            }
-
-            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-                reportingConfiguration(reportingConfiguration.orElse(null))
-
-            fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-                this.shippingAddress = shippingAddress
-            }
-
-            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-                shippingAddress(shippingAddress.orElse(null))
-
-            fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-                this.taxConfiguration = taxConfiguration
-            }
-
-            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-                taxConfiguration(taxConfiguration.orElse(null))
-
-            fun taxConfiguration(
-                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-            ) = apply {
-                this.taxConfiguration =
-                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
-            }
-
-            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-                apply {
-                    this.taxConfiguration =
-                        TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration)
-                }
+            fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+                this.paymentProviderId = paymentProviderId
+            }
+
+            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) =
+                reportingConfiguration(JsonField.ofNullable(reportingConfiguration))
+
+            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+                reportingConfiguration(reportingConfiguration.orElse(null))
+
+            fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+                apply {
+                    this.reportingConfiguration = reportingConfiguration
+                }
+
+            fun shippingAddress(shippingAddress: ShippingAddress?) =
+                shippingAddress(JsonField.ofNullable(shippingAddress))
+
+            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+                shippingAddress(shippingAddress.orElse(null))
+
+            fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+                this.shippingAddress = shippingAddress
+            }
+
+            fun taxConfiguration(taxConfiguration: TaxConfiguration?) =
+                taxConfiguration(JsonField.ofNullable(taxConfiguration))
+
+            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+                taxConfiguration(taxConfiguration.orElse(null))
+
+            fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+                this.taxConfiguration = taxConfiguration
+            }
+
+            fun taxConfiguration(
+                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+            ) =
+                taxConfiguration(
+                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
+                )
+
+            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+                taxConfiguration(TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration))
+
+            /**
+             * Tax IDs are commonly required to be displayed on customer invoices, which are added
+             * to the headers of invoices.
+             *
+             * ### Supported Tax ID Countries and Types
+             * |Country             |Type        |Description                                                                                            |
+             * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+             * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+             * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+             * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+             * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+             * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+             * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+             * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+             * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+             * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+             * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+             * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+             * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+             * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+             * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+             * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+             * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+             * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+             * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+             * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+             * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+             * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+             * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+             * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+             * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+             * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+             * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |France              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+             * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+             * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+             * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+             * |India               |`in_gst`    |Indian GST Number                                                                                      |
+             * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+             * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+             * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+             * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+             * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+             * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+             * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+             * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+             * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+             * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+             * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+             * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+             * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+             * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+             * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+             * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+             * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+             * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+             * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+             * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+             * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+             * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+             * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+             * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+             * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+             * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+             * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+             * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+             * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+             * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+             * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+             * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+             * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+             * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+             * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+             * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+             * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+             * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+             * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+             * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+             * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+             * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+             * |United States       |`us_ein`    |United States EIN                                                                                      |
+             * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+             * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+             * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+             */
+            fun taxId(taxId: TaxId?) = taxId(JsonField.ofNullable(taxId))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -803,7 +1455,7 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: TaxId?) = apply { this.taxId = taxId }
+            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -911,14 +1563,14 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+            fun taxId(taxId: JsonField<TaxId>) = apply { this.taxId = taxId }
 
             /**
              * A timezone identifier from the IANA timezone database, such as
              * `"America/Los_Angeles"`. This defaults to your account's timezone if not set. This
              * cannot be changed after customer creation.
              */
-            fun timezone(timezone: String?) = apply { this.timezone = timezone }
+            fun timezone(timezone: String?) = timezone(JsonField.ofNullable(timezone))
 
             /**
              * A timezone identifier from the IANA timezone database, such as
@@ -927,6 +1579,13 @@ constructor(
              */
             fun timezone(timezone: Optional<String>) = timezone(timezone.orElse(null))
 
+            /**
+             * A timezone identifier from the IANA timezone database, such as
+             * `"America/Los_Angeles"`. This defaults to your account's timezone if not set. This
+             * cannot be changed after customer creation.
+             */
+            fun timezone(timezone: JsonField<String>) = apply { this.timezone = timezone }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -951,7 +1610,7 @@ constructor(
                     checkNotNull(email) { "`email` is required but was not set" },
                     checkNotNull(name) { "`name` is required but was not set" },
                     accountingSyncConfiguration,
-                    additionalEmails?.toImmutable(),
+                    (additionalEmails ?: JsonMissing.of()).map { it.toImmutable() },
                     autoCollection,
                     billingAddress,
                     currency,
@@ -1014,9 +1673,18 @@ constructor(
          */
         fun email(email: String) = apply { body.email(email) }
 
+        /**
+         * A valid customer email, to be used for notifications. When Orb triggers payment through a
+         * payment gateway, this email will be used for any automatically issued receipts.
+         */
+        fun email(email: JsonField<String>) = apply { body.email(email) }
+
         /** The full name of the customer */
         fun name(name: String) = apply { body.name(name) }
 
+        /** The full name of the customer */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         fun accountingSyncConfiguration(accountingSyncConfiguration: AccountingSyncConfiguration?) =
             apply {
                 body.accountingSyncConfiguration(accountingSyncConfiguration)
@@ -1026,6 +1694,10 @@ constructor(
             accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
         ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+        fun accountingSyncConfiguration(
+            accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+        ) = apply { body.accountingSyncConfiguration(accountingSyncConfiguration) }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1041,6 +1713,14 @@ constructor(
         fun additionalEmails(additionalEmails: Optional<List<String>>) =
             additionalEmails(additionalEmails.orElse(null))
 
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+            body.additionalEmails(additionalEmails)
+        }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1072,6 +1752,15 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         fun billingAddress(billingAddress: BillingAddress?) = apply {
             body.billingAddress(billingAddress)
         }
@@ -1079,6 +1768,10 @@ constructor(
         fun billingAddress(billingAddress: Optional<BillingAddress>) =
             billingAddress(billingAddress.orElse(null))
 
+        fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+            body.billingAddress(billingAddress)
+        }
+
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
@@ -1091,6 +1784,12 @@ constructor(
          */
         fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         fun emailDelivery(emailDelivery: Boolean?) = apply { body.emailDelivery(emailDelivery) }
 
         fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
@@ -1099,6 +1798,10 @@ constructor(
         fun emailDelivery(emailDelivery: Optional<Boolean>) =
             emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+        fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+            body.emailDelivery(emailDelivery)
+        }
+
         /**
          * An optional user-defined ID for this customer resource, used throughout the system as an
          * alias for this Customer. Use this field to identify a customer by an existing identifier
@@ -1116,6 +1819,15 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /**
+         * An optional user-defined ID for this customer resource, used throughout the system as an
+         * alias for this Customer. Use this field to identify a customer by an existing identifier
+         * in your system.
+         */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -1130,6 +1842,13 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
          * test mode, the connection must first be configured in the Orb webapp.
@@ -1145,6 +1864,14 @@ constructor(
         fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
             paymentProvider(paymentProvider.orElse(null))
 
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode, the connection must first be configured in the Orb webapp.
+         */
+        fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+            body.paymentProvider(paymentProvider)
+        }
+
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
@@ -1157,38 +1884,167 @@ constructor(
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
-        fun paymentProviderId(paymentProviderId: Optional<String>) =
-            paymentProviderId(paymentProviderId.orElse(null))
-
-        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-            body.reportingConfiguration(reportingConfiguration)
-        }
-
-        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-            reportingConfiguration(reportingConfiguration.orElse(null))
-
-        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-            body.shippingAddress(shippingAddress)
-        }
-
-        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-            shippingAddress(shippingAddress.orElse(null))
-
-        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-            body.taxConfiguration(taxConfiguration)
-        }
-
-        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-            taxConfiguration(taxConfiguration.orElse(null))
-
-        fun taxConfiguration(
-            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
-
-        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-            apply {
-                body.taxConfiguration(newTaxJarConfiguration)
-            }
+        fun paymentProviderId(paymentProviderId: Optional<String>) =
+            paymentProviderId(paymentProviderId.orElse(null))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+            body.paymentProviderId(paymentProviderId)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
+            body.reportingConfiguration(reportingConfiguration)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+            reportingConfiguration(reportingConfiguration.orElse(null))
+
+        fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+            apply {
+                body.reportingConfiguration(reportingConfiguration)
+            }
+
+        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
+
+        fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+            taxConfiguration(taxConfiguration.orElse(null))
+
+        fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(
+            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
+
+        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+            apply {
+                body.taxConfiguration(newTaxJarConfiguration)
+            }
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1296,7 +2152,7 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
+        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1404,7 +2260,7 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+        fun taxId(taxId: JsonField<TaxId>) = apply { body.taxId(taxId) }
 
         /**
          * A timezone identifier from the IANA timezone database, such as `"America/Los_Angeles"`.
@@ -1420,6 +2276,32 @@ constructor(
          */
         fun timezone(timezone: Optional<String>) = timezone(timezone.orElse(null))
 
+        /**
+         * A timezone identifier from the IANA timezone database, such as `"America/Los_Angeles"`.
+         * This defaults to your account's timezone if not set. This cannot be changed after
+         * customer creation.
+         */
+        fun timezone(timezone: JsonField<String>) = apply { body.timezone(timezone) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -1518,25 +2400,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerCreateParams =
             CustomerCreateParams(
                 body.build(),
@@ -1550,22 +2413,40 @@ constructor(
     @JsonCreator
     private constructor(
         @JsonProperty("accounting_providers")
-        private val accountingProviders: List<AccountingProvider>?,
-        @JsonProperty("excluded") private val excluded: Boolean?,
+        @ExcludeMissing
+        private val accountingProviders: JsonField<List<AccountingProvider>> = JsonMissing.of(),
+        @JsonProperty("excluded")
+        @ExcludeMissing
+        private val excluded: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("accounting_providers")
         fun accountingProviders(): Optional<List<AccountingProvider>> =
-            Optional.ofNullable(accountingProviders)
+            Optional.ofNullable(accountingProviders.getNullable("accounting_providers"))
+
+        fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded.getNullable("excluded"))
+
+        @JsonProperty("accounting_providers")
+        @ExcludeMissing
+        fun _accountingProviders(): JsonField<List<AccountingProvider>> = accountingProviders
 
-        @JsonProperty("excluded") fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded)
+        @JsonProperty("excluded") @ExcludeMissing fun _excluded(): JsonField<Boolean> = excluded
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AccountingSyncConfiguration = apply {
+            if (!validated) {
+                accountingProviders().map { it.forEach { it.validate() } }
+                excluded()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1575,38 +2456,52 @@ constructor(
 
         class Builder {
 
-            private var accountingProviders: MutableList<AccountingProvider>? = null
-            private var excluded: Boolean? = null
+            private var accountingProviders: JsonField<MutableList<AccountingProvider>>? = null
+            private var excluded: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(accountingSyncConfiguration: AccountingSyncConfiguration) = apply {
                 accountingProviders =
-                    accountingSyncConfiguration.accountingProviders?.toMutableList()
+                    accountingSyncConfiguration.accountingProviders.map { it.toMutableList() }
                 excluded = accountingSyncConfiguration.excluded
                 additionalProperties =
                     accountingSyncConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun accountingProviders(accountingProviders: List<AccountingProvider>?) = apply {
-                this.accountingProviders = accountingProviders?.toMutableList()
-            }
+            fun accountingProviders(accountingProviders: List<AccountingProvider>?) =
+                accountingProviders(JsonField.ofNullable(accountingProviders))
 
             fun accountingProviders(accountingProviders: Optional<List<AccountingProvider>>) =
                 accountingProviders(accountingProviders.orElse(null))
 
+            fun accountingProviders(accountingProviders: JsonField<List<AccountingProvider>>) =
+                apply {
+                    this.accountingProviders = accountingProviders.map { it.toMutableList() }
+                }
+
             fun addAccountingProvider(accountingProvider: AccountingProvider) = apply {
                 accountingProviders =
-                    (accountingProviders ?: mutableListOf()).apply { add(accountingProvider) }
+                    (accountingProviders ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(accountingProvider)
+                    }
             }
 
-            fun excluded(excluded: Boolean?) = apply { this.excluded = excluded }
+            fun excluded(excluded: Boolean?) = excluded(JsonField.ofNullable(excluded))
 
             fun excluded(excluded: Boolean) = excluded(excluded as Boolean?)
 
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun excluded(excluded: Optional<Boolean>) = excluded(excluded.orElse(null) as Boolean?)
 
+            fun excluded(excluded: JsonField<Boolean>) = apply { this.excluded = excluded }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1628,7 +2523,7 @@ constructor(
 
             fun build(): AccountingSyncConfiguration =
                 AccountingSyncConfiguration(
-                    accountingProviders?.toImmutable(),
+                    (accountingProviders ?: JsonMissing.of()).map { it.toImmutable() },
                     excluded,
                     additionalProperties.toImmutable(),
                 )
@@ -1638,21 +2533,43 @@ constructor(
         class AccountingProvider
         @JsonCreator
         private constructor(
-            @JsonProperty("external_provider_id") private val externalProviderId: String,
-            @JsonProperty("provider_type") private val providerType: String,
+            @JsonProperty("external_provider_id")
+            @ExcludeMissing
+            private val externalProviderId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            private val providerType: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
+            fun externalProviderId(): String =
+                externalProviderId.getRequired("external_provider_id")
+
+            fun providerType(): String = providerType.getRequired("provider_type")
+
             @JsonProperty("external_provider_id")
-            fun externalProviderId(): String = externalProviderId
+            @ExcludeMissing
+            fun _externalProviderId(): JsonField<String> = externalProviderId
 
-            @JsonProperty("provider_type") fun providerType(): String = providerType
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            fun _providerType(): JsonField<String> = providerType
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): AccountingProvider = apply {
+                if (!validated) {
+                    externalProviderId()
+                    providerType()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1662,8 +2579,8 @@ constructor(
 
             class Builder {
 
-                private var externalProviderId: String? = null
-                private var providerType: String? = null
+                private var externalProviderId: JsonField<String>? = null
+                private var providerType: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1673,11 +2590,18 @@ constructor(
                     additionalProperties = accountingProvider.additionalProperties.toMutableMap()
                 }
 
-                fun externalProviderId(externalProviderId: String) = apply {
+                fun externalProviderId(externalProviderId: String) =
+                    externalProviderId(JsonField.of(externalProviderId))
+
+                fun externalProviderId(externalProviderId: JsonField<String>) = apply {
                     this.externalProviderId = externalProviderId
                 }
 
-                fun providerType(providerType: String) = apply { this.providerType = providerType }
+                fun providerType(providerType: String) = providerType(JsonField.of(providerType))
+
+                fun providerType(providerType: JsonField<String>) = apply {
+                    this.providerType = providerType
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1751,33 +2675,73 @@ constructor(
     class BillingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
+
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
+
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): BillingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1787,12 +2751,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1806,30 +2770,42 @@ constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1896,6 +2872,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2030,17 +3014,30 @@ constructor(
     class ReportingConfiguration
     @JsonCreator
     private constructor(
-        @JsonProperty("exempt") private val exempt: Boolean,
+        @JsonProperty("exempt")
+        @ExcludeMissing
+        private val exempt: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("exempt") fun exempt(): Boolean = exempt
+        fun exempt(): Boolean = exempt.getRequired("exempt")
+
+        @JsonProperty("exempt") @ExcludeMissing fun _exempt(): JsonField<Boolean> = exempt
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReportingConfiguration = apply {
+            if (!validated) {
+                exempt()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2050,7 +3047,7 @@ constructor(
 
         class Builder {
 
-            private var exempt: Boolean? = null
+            private var exempt: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2059,7 +3056,9 @@ constructor(
                 additionalProperties = reportingConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun exempt(exempt: Boolean) = apply { this.exempt = exempt }
+            fun exempt(exempt: Boolean) = exempt(JsonField.of(exempt))
+
+            fun exempt(exempt: JsonField<Boolean>) = apply { this.exempt = exempt }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -2109,33 +3108,73 @@ constructor(
     class ShippingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
+
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
+
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ShippingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2145,12 +3184,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2164,30 +3203,42 @@ constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2246,6 +3297,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun newAvalaraTaxConfiguration(): Optional<NewAvalaraTaxConfiguration> =
             Optional.ofNullable(newAvalaraTaxConfiguration)
 
@@ -2274,6 +3327,17 @@ constructor(
             }
         }
 
+        fun validate(): TaxConfiguration = apply {
+            if (!validated) {
+                if (newAvalaraTaxConfiguration == null && newTaxJarConfiguration == null) {
+                    throw OrbInvalidDataException("Unknown TaxConfiguration: $_json")
+                }
+                newAvalaraTaxConfiguration?.validate()
+                newTaxJarConfiguration?.validate()
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
@@ -2328,14 +3392,23 @@ constructor(
 
                 when (taxProvider) {
                     "avalara" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>())?.let {
-                            return TaxConfiguration(newAvalaraTaxConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(
+                                    newAvalaraTaxConfiguration = it,
+                                    _json = json
+                                )
+                            }
                     }
                     "taxjar" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>())?.let {
-                            return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
+                            }
                     }
                 }
 
@@ -2365,24 +3438,53 @@ constructor(
         class NewAvalaraTaxConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
-            @JsonProperty("tax_exemption_code") private val taxExemptionCode: String?,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
+            @JsonProperty("tax_exemption_code")
+            @ExcludeMissing
+            private val taxExemptionCode: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            fun taxExemptionCode(): Optional<String> =
+                Optional.ofNullable(taxExemptionCode.getNullable("tax_exemption_code"))
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
+
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonProperty("tax_exemption_code")
-            fun taxExemptionCode(): Optional<String> = Optional.ofNullable(taxExemptionCode)
+            @ExcludeMissing
+            fun _taxExemptionCode(): JsonField<String> = taxExemptionCode
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewAvalaraTaxConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    taxExemptionCode()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2392,9 +3494,9 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
-                private var taxExemptionCode: String? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
+                private var taxExemptionCode: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2406,17 +3508,26 @@ constructor(
                         newAvalaraTaxConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxExemptionCode(taxExemptionCode: String?) = apply {
-                    this.taxExemptionCode = taxExemptionCode
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
                 }
 
+                fun taxExemptionCode(taxExemptionCode: String?) =
+                    taxExemptionCode(JsonField.ofNullable(taxExemptionCode))
+
                 fun taxExemptionCode(taxExemptionCode: Optional<String>) =
                     taxExemptionCode(taxExemptionCode.orElse(null))
 
+                fun taxExemptionCode(taxExemptionCode: JsonField<String>) = apply {
+                    this.taxExemptionCode = taxExemptionCode
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -2521,20 +3632,42 @@ constructor(
         class NewTaxJarConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewTaxJarConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2544,8 +3677,8 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2556,9 +3689,15 @@ constructor(
                         newTaxJarConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
+
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -2770,23 +3909,44 @@ constructor(
     class TaxId
     @JsonCreator
     private constructor(
-        @JsonProperty("country") private val country: Country,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("value") private val value: String,
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<Country> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("country") fun country(): Country = country
+        fun country(): Country = country.getRequired("country")
+
+        fun type(): Type = type.getRequired("type")
+
+        fun value(): String = value.getRequired("value")
 
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("value") fun value(): String = value
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
+
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): TaxId = apply {
+            if (!validated) {
+                country()
+                type()
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2796,9 +3956,9 @@ constructor(
 
         class Builder {
 
-            private var country: Country? = null
-            private var type: Type? = null
-            private var value: String? = null
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2809,11 +3969,17 @@ constructor(
                 additionalProperties = taxId.additionalProperties.toMutableMap()
             }
 
-            fun country(country: Country) = apply { this.country = country }
+            fun country(country: Country) = country(JsonField.of(country))
+
+            fun country(country: JsonField<Country>) = apply { this.country = country }
+
+            fun type(type: Type) = type(JsonField.of(type))
+
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
-            fun type(type: Type) = apply { this.type = type }
+            fun value(value: String) = value(JsonField.of(value))
 
-            fun value(value: String) = apply { this.value = value }
+            fun value(value: JsonField<String>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdParams.kt
index b614b8e3..6273e81b 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -32,6 +33,108 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint allows you to create a new ledger entry for a specified customer's balance. This
+ * can be used to increment balance, deduct credits, and change the expiry date of existing credits.
+ *
+ * ## Effects of adding a ledger entry
+ * 1. After calling this endpoint, [Fetch Credit Balance](fetch-customer-credits) will return a
+ *    credit block that represents the changes (i.e. balance changes or transfers).
+ * 2. A ledger entry will be added to the credits ledger for this customer, and therefore returned
+ *    in the [View Credits Ledger](fetch-customer-credits-ledger) response as well as serialized in
+ *    the response to this request. In the case of deductions without a specified block, multiple
+ *    ledger entries may be created if the deduction spans credit blocks.
+ * 3. If `invoice_settings` is specified, an invoice will be created that reflects the cost of the
+ *    credits (based on `amount` and `per_unit_cost_basis`).
+ *
+ * ## Adding credits
+ *
+ * Adding credits is done by creating an entry of type `increment`. This requires the caller to
+ * specify a number of credits as well as an optional expiry date in `YYYY-MM-DD` format. Orb also
+ * recommends specifying a description to assist with auditing. When adding credits, the caller can
+ * also specify a cost basis per-credit, to indicate how much in USD a customer paid for a single
+ * credit in a block. This can later be used for revenue recognition.
+ *
+ * The following snippet illustrates a sample request body to increment credits which will expire in
+ * January of 2022.
+ *
+ * ```json
+ * {
+ *   "entry_type": "increment",
+ *   "amount": 100,
+ *   "expiry_date": "2022-12-28",
+ *   "per_unit_cost_basis": "0.20",
+ *   "description": "Purchased 100 credits"
+ * }
+ * ```
+ *
+ * Note that by default, Orb will always first increment any _negative_ balance in existing blocks
+ * before adding the remaining amount to the desired credit block.
+ *
+ * ### Invoicing for credits
+ *
+ * By default, Orb manipulates the credit ledger but does not charge for credits. However, if you
+ * pass `invoice_settings` in the body of this request, Orb will also generate a one-off invoice for
+ * the customer for the credits pre-purchase. Note that you _must_ provide the
+ * `per_unit_cost_basis`, since the total charges on the invoice are calculated by multiplying the
+ * cost basis with the number of credit units added.
+ *
+ * ## Deducting Credits
+ *
+ * Orb allows you to deduct credits from a customer by creating an entry of type `decrement`. Orb
+ * matches the algorithm for automatic deductions for determining which credit blocks to decrement
+ * from. In the case that the deduction leads to multiple ledger entries, the response from this
+ * endpoint will be the final deduction. Orb also optionally allows specifying a description to
+ * assist with auditing.
+ *
+ * The following snippet illustrates a sample request body to decrement credits.
+ *
+ * ```json
+ * {
+ *   "entry_type": "decrement",
+ *   "amount": 20,
+ *   "description": "Removing excess credits"
+ * }
+ * ```
+ *
+ * ## Changing credits expiry
+ *
+ * If you'd like to change when existing credits expire, you should create a ledger entry of type
+ * `expiration_change`. For this entry, the required parameter `expiry_date` identifies the
+ * _originating_ block, and the required parameter `target_expiry_date` identifies when the
+ * transferred credits should now expire. A new credit block will be created with expiry date
+ * `target_expiry_date`, with the same cost basis data as the original credit block, if present.
+ *
+ * Note that the balance of the block with the given `expiry_date` must be at least equal to the
+ * desired transfer amount determined by the `amount` parameter.
+ *
+ * The following snippet illustrates a sample request body to extend the expiration date of credits
+ * by one year:
+ * ```json
+ * {
+ *   "entry_type": "expiration_change",
+ *   "amount": 10,
+ *   "expiry_date": "2022-12-28",
+ *   "block_id": "UiUhFWeLHPrBY4Ad",
+ *   "target_expiry_date": "2023-12-28",
+ *   "description": "Extending credit validity"
+ * }
+ * ```
+ *
+ * ## Voiding credits
+ *
+ * If you'd like to void a credit block, create a ledger entry of type `void`. For this entry,
+ * `block_id` is required to identify the block, and `amount` indicates how many credits to void, up
+ * to the block's initial balance. Pass in a `void_reason` of `refund` if the void is due to a
+ * refund.
+ *
+ * ## Amendment
+ *
+ * If you'd like to undo a decrement on a credit block, create a ledger entry of type `amendment`.
+ * For this entry, `block_id` is required to identify the block that was originally decremented
+ * from, and `amount` indicates how many credits to return to the customer, up to the block's
+ * initial balance.
+ */
 class CustomerCreditLedgerCreateEntryByExternalIdParams
 constructor(
     private val externalCustomerId: String,
@@ -611,15 +714,33 @@ constructor(
     class AddIncrementCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("effective_date") private val effectiveDate: OffsetDateTime?,
-        @JsonProperty("expiry_date") private val expiryDate: OffsetDateTime?,
-        @JsonProperty("invoice_settings") private val invoiceSettings: InvoiceSettings?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("per_unit_cost_basis") private val perUnitCostBasis: String?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("effective_date")
+        @ExcludeMissing
+        private val effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("expiry_date")
+        @ExcludeMissing
+        private val expiryDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        private val invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        private val perUnitCostBasis: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -628,15 +749,72 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
+
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * An ISO 8601 format date that denotes when this credit balance should become available for
+         * use.
+         */
+        fun effectiveDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(effectiveDate.getNullable("effective_date"))
+
+        /** An ISO 8601 format date that denotes when this credit balance should expire. */
+        fun expiryDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(expiryDate.getNullable("expiry_date"))
+
+        /**
+         * Passing `invoice_settings` automatically generates an invoice for the newly added
+         * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as the
+         * calculation of the invoice total is done on that basis.
+         */
+        fun invoiceSettings(): Optional<InvoiceSettings> =
+            Optional.ofNullable(invoiceSettings.getNullable("invoice_settings"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * Can only be specified when entry_type=increment. How much, in the customer's currency, a
+         * customer paid for a single credit in this block
+         */
+        fun perUnitCostBasis(): Optional<String> =
+            Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -644,18 +822,21 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * An ISO 8601 format date that denotes when this credit balance should become available for
          * use.
          */
         @JsonProperty("effective_date")
-        fun effectiveDate(): Optional<OffsetDateTime> = Optional.ofNullable(effectiveDate)
+        @ExcludeMissing
+        fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
         /** An ISO 8601 format date that denotes when this credit balance should expire. */
         @JsonProperty("expiry_date")
-        fun expiryDate(): Optional<OffsetDateTime> = Optional.ofNullable(expiryDate)
+        @ExcludeMissing
+        fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
         /**
          * Passing `invoice_settings` automatically generates an invoice for the newly added
@@ -663,26 +844,45 @@ constructor(
          * calculation of the invoice total is done on that basis.
          */
         @JsonProperty("invoice_settings")
-        fun invoiceSettings(): Optional<InvoiceSettings> = Optional.ofNullable(invoiceSettings)
+        @ExcludeMissing
+        fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * Can only be specified when entry_type=increment. How much, in the customer's currency, a
          * customer paid for a single credit in this block
          */
         @JsonProperty("per_unit_cost_basis")
-        fun perUnitCostBasis(): Optional<String> = Optional.ofNullable(perUnitCostBasis)
+        @ExcludeMissing
+        fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddIncrementCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                entryType()
+                currency()
+                description()
+                effectiveDate()
+                expiryDate()
+                invoiceSettings().map { it.validate() }
+                metadata().map { it.validate() }
+                perUnitCostBasis()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -692,15 +892,15 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var effectiveDate: OffsetDateTime? = null
-            private var expiryDate: OffsetDateTime? = null
-            private var invoiceSettings: InvoiceSettings? = null
-            private var metadata: Metadata? = null
-            private var perUnitCostBasis: String? = null
+            private var amount: JsonField<Double>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -725,15 +925,23 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -741,12 +949,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -755,13 +969,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * An ISO 8601 format date that denotes when this credit balance should become available
              * for use.
              */
-            fun effectiveDate(effectiveDate: OffsetDateTime?) = apply {
-                this.effectiveDate = effectiveDate
-            }
+            fun effectiveDate(effectiveDate: OffsetDateTime?) =
+                effectiveDate(JsonField.ofNullable(effectiveDate))
 
             /**
              * An ISO 8601 format date that denotes when this credit balance should become available
@@ -770,21 +992,34 @@ constructor(
             fun effectiveDate(effectiveDate: Optional<OffsetDateTime>) =
                 effectiveDate(effectiveDate.orElse(null))
 
+            /**
+             * An ISO 8601 format date that denotes when this credit balance should become available
+             * for use.
+             */
+            fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
+                this.effectiveDate = effectiveDate
+            }
+
             /** An ISO 8601 format date that denotes when this credit balance should expire. */
-            fun expiryDate(expiryDate: OffsetDateTime?) = apply { this.expiryDate = expiryDate }
+            fun expiryDate(expiryDate: OffsetDateTime?) =
+                expiryDate(JsonField.ofNullable(expiryDate))
 
             /** An ISO 8601 format date that denotes when this credit balance should expire. */
             fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
                 expiryDate(expiryDate.orElse(null))
 
+            /** An ISO 8601 format date that denotes when this credit balance should expire. */
+            fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
+                this.expiryDate = expiryDate
+            }
+
             /**
              * Passing `invoice_settings` automatically generates an invoice for the newly added
              * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as
              * the calculation of the invoice total is done on that basis.
              */
-            fun invoiceSettings(invoiceSettings: InvoiceSettings?) = apply {
-                this.invoiceSettings = invoiceSettings
-            }
+            fun invoiceSettings(invoiceSettings: InvoiceSettings?) =
+                invoiceSettings(JsonField.ofNullable(invoiceSettings))
 
             /**
              * Passing `invoice_settings` automatically generates an invoice for the newly added
@@ -794,12 +1029,21 @@ constructor(
             fun invoiceSettings(invoiceSettings: Optional<InvoiceSettings>) =
                 invoiceSettings(invoiceSettings.orElse(null))
 
+            /**
+             * Passing `invoice_settings` automatically generates an invoice for the newly added
+             * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as
+             * the calculation of the invoice total is done on that basis.
+             */
+            fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
+                this.invoiceSettings = invoiceSettings
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -808,13 +1052,19 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * Can only be specified when entry_type=increment. How much, in the customer's
              * currency, a customer paid for a single credit in this block
              */
-            fun perUnitCostBasis(perUnitCostBasis: String?) = apply {
-                this.perUnitCostBasis = perUnitCostBasis
-            }
+            fun perUnitCostBasis(perUnitCostBasis: String?) =
+                perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
 
             /**
              * Can only be specified when entry_type=increment. How much, in the customer's
@@ -823,6 +1073,14 @@ constructor(
             fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
                 perUnitCostBasis(perUnitCostBasis.orElse(null))
 
+            /**
+             * Can only be specified when entry_type=increment. How much, in the customer's
+             * currency, a customer paid for a single credit in this block
+             */
+            fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
+                this.perUnitCostBasis = perUnitCostBasis
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -917,11 +1175,18 @@ constructor(
         class InvoiceSettings
         @JsonCreator
         private constructor(
-            @JsonProperty("auto_collection") private val autoCollection: Boolean,
-            @JsonProperty("net_terms") private val netTerms: Long,
-            @JsonProperty("memo") private val memo: String?,
+            @JsonProperty("auto_collection")
+            @ExcludeMissing
+            private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("net_terms")
+            @ExcludeMissing
+            private val netTerms: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("memo")
+            @ExcludeMissing
+            private val memo: JsonField<String> = JsonMissing.of(),
             @JsonProperty("require_successful_payment")
-            private val requireSuccessfulPayment: Boolean?,
+            @ExcludeMissing
+            private val requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
@@ -930,29 +1195,67 @@ constructor(
              * Whether the credits purchase invoice should auto collect with the customer's saved
              * payment method.
              */
-            @JsonProperty("auto_collection") fun autoCollection(): Boolean = autoCollection
+            fun autoCollection(): Boolean = autoCollection.getRequired("auto_collection")
 
             /**
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0.
              */
-            @JsonProperty("net_terms") fun netTerms(): Long = netTerms
+            fun netTerms(): Long = netTerms.getRequired("net_terms")
 
             /** An optional memo to display on the invoice. */
-            @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+            fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
 
             /**
              * If true, the new credit block will require that the corresponding invoice is paid
              * before it can be drawn down from.
              */
-            @JsonProperty("require_successful_payment")
             fun requireSuccessfulPayment(): Optional<Boolean> =
-                Optional.ofNullable(requireSuccessfulPayment)
+                Optional.ofNullable(
+                    requireSuccessfulPayment.getNullable("require_successful_payment")
+                )
+
+            /**
+             * Whether the credits purchase invoice should auto collect with the customer's saved
+             * payment method.
+             */
+            @JsonProperty("auto_collection")
+            @ExcludeMissing
+            fun _autoCollection(): JsonField<Boolean> = autoCollection
+
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0.
+             */
+            @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
+
+            /** An optional memo to display on the invoice. */
+            @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
+
+            /**
+             * If true, the new credit block will require that the corresponding invoice is paid
+             * before it can be drawn down from.
+             */
+            @JsonProperty("require_successful_payment")
+            @ExcludeMissing
+            fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoiceSettings = apply {
+                if (!validated) {
+                    autoCollection()
+                    netTerms()
+                    memo()
+                    requireSuccessfulPayment()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -962,10 +1265,10 @@ constructor(
 
             class Builder {
 
-                private var autoCollection: Boolean? = null
-                private var netTerms: Long? = null
-                private var memo: String? = null
-                private var requireSuccessfulPayment: Boolean? = null
+                private var autoCollection: JsonField<Boolean>? = null
+                private var netTerms: JsonField<Long>? = null
+                private var memo: JsonField<String> = JsonMissing.of()
+                private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -981,7 +1284,14 @@ constructor(
                  * Whether the credits purchase invoice should auto collect with the customer's
                  * saved payment method.
                  */
-                fun autoCollection(autoCollection: Boolean) = apply {
+                fun autoCollection(autoCollection: Boolean) =
+                    autoCollection(JsonField.of(autoCollection))
+
+                /**
+                 * Whether the credits purchase invoice should auto collect with the customer's
+                 * saved payment method.
+                 */
+                fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
                     this.autoCollection = autoCollection
                 }
 
@@ -990,36 +1300,38 @@ constructor(
                  * date for the invoice. If you intend the invoice to be due on issue, set this
                  * to 0.
                  */
-                fun netTerms(netTerms: Long) = apply { this.netTerms = netTerms }
+                fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+
+                /**
+                 * The net terms determines the difference between the invoice date and the issue
+                 * date for the invoice. If you intend the invoice to be due on issue, set this
+                 * to 0.
+                 */
+                fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
                 /** An optional memo to display on the invoice. */
-                fun memo(memo: String?) = apply { this.memo = memo }
+                fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
                 /** An optional memo to display on the invoice. */
                 fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
-                /**
-                 * If true, the new credit block will require that the corresponding invoice is paid
-                 * before it can be drawn down from.
-                 */
-                fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean?) = apply {
-                    this.requireSuccessfulPayment = requireSuccessfulPayment
-                }
+                /** An optional memo to display on the invoice. */
+                fun memo(memo: JsonField<String>) = apply { this.memo = memo }
 
                 /**
                  * If true, the new credit block will require that the corresponding invoice is paid
                  * before it can be drawn down from.
                  */
                 fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean) =
-                    requireSuccessfulPayment(requireSuccessfulPayment as Boolean?)
+                    requireSuccessfulPayment(JsonField.of(requireSuccessfulPayment))
 
                 /**
                  * If true, the new credit block will require that the corresponding invoice is paid
                  * before it can be drawn down from.
                  */
-                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                fun requireSuccessfulPayment(requireSuccessfulPayment: Optional<Boolean>) =
-                    requireSuccessfulPayment(requireSuccessfulPayment.orElse(null) as Boolean?)
+                fun requireSuccessfulPayment(requireSuccessfulPayment: JsonField<Boolean>) = apply {
+                    this.requireSuccessfulPayment = requireSuccessfulPayment
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1090,6 +1402,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1170,11 +1490,21 @@ constructor(
     class AddDecrementCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -1183,15 +1513,46 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1199,19 +1560,33 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddDecrementCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1221,11 +1596,11 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var amount: JsonField<Double>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1246,15 +1621,23 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1262,12 +1645,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1276,12 +1665,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1290,6 +1688,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1388,6 +1793,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1468,47 +1881,113 @@ constructor(
     class AddExpirationChangeCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("expiry_date") private val expiryDate: OffsetDateTime?,
-        @JsonProperty("target_expiry_date") private val targetExpiryDate: LocalDate,
-        @JsonProperty("amount") private val amount: Double?,
-        @JsonProperty("block_id") private val blockId: String?,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("expiry_date")
+        @ExcludeMissing
+        private val expiryDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("target_expiry_date")
+        @ExcludeMissing
+        private val targetExpiryDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /** An ISO 8601 format date that identifies the origination credit block to expire */
+        fun expiryDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(expiryDate.getNullable("expiry_date"))
+
+        /**
+         * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting when
+         * credits transferred (as part of a partial block expiration) should expire.
+         */
+        fun targetExpiryDate(): LocalDate = targetExpiryDate.getRequired("target_expiry_date")
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        fun amount(): Optional<Double> = Optional.ofNullable(amount.getNullable("amount"))
+
+        /**
+         * The ID of the block affected by an expiration_change, used to differentiate between
+         * multiple blocks with the same `expiry_date`.
+         */
+        fun blockId(): Optional<String> = Optional.ofNullable(blockId.getNullable("block_id"))
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /** An ISO 8601 format date that identifies the origination credit block to expire */
         @JsonProperty("expiry_date")
-        fun expiryDate(): Optional<OffsetDateTime> = Optional.ofNullable(expiryDate)
+        @ExcludeMissing
+        fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
         /**
          * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting when
          * credits transferred (as part of a partial block expiration) should expire.
          */
-        @JsonProperty("target_expiry_date") fun targetExpiryDate(): LocalDate = targetExpiryDate
+        @JsonProperty("target_expiry_date")
+        @ExcludeMissing
+        fun _targetExpiryDate(): JsonField<LocalDate> = targetExpiryDate
 
         /**
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Optional<Double> = Optional.ofNullable(amount)
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
         /**
          * The ID of the block affected by an expiration_change, used to differentiate between
          * multiple blocks with the same `expiry_date`.
          */
-        @JsonProperty("block_id") fun blockId(): Optional<String> = Optional.ofNullable(blockId)
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1516,19 +1995,36 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddExpirationChangeCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                entryType()
+                expiryDate()
+                targetExpiryDate()
+                amount()
+                blockId()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1538,14 +2034,14 @@ constructor(
 
         class Builder {
 
-            private var entryType: EntryType? = null
-            private var expiryDate: OffsetDateTime? = null
-            private var targetExpiryDate: LocalDate? = null
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var expiryDate: JsonField<OffsetDateTime>? = null
+            private var targetExpiryDate: JsonField<LocalDate>? = null
+            private var amount: JsonField<Double> = JsonMissing.of()
+            private var blockId: JsonField<String> = JsonMissing.of()
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1567,20 +2063,35 @@ constructor(
                         .toMutableMap()
             }
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /** An ISO 8601 format date that identifies the origination credit block to expire */
-            fun expiryDate(expiryDate: OffsetDateTime?) = apply { this.expiryDate = expiryDate }
+            fun expiryDate(expiryDate: OffsetDateTime?) =
+                expiryDate(JsonField.ofNullable(expiryDate))
 
             /** An ISO 8601 format date that identifies the origination credit block to expire */
             fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
                 expiryDate(expiryDate.orElse(null))
 
+            /** An ISO 8601 format date that identifies the origination credit block to expire */
+            fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
+                this.expiryDate = expiryDate
+            }
+
+            /**
+             * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting
+             * when credits transferred (as part of a partial block expiration) should expire.
+             */
+            fun targetExpiryDate(targetExpiryDate: LocalDate) =
+                targetExpiryDate(JsonField.of(targetExpiryDate))
+
             /**
              * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting
              * when credits transferred (as part of a partial block expiration) should expire.
              */
-            fun targetExpiryDate(targetExpiryDate: LocalDate) = apply {
+            fun targetExpiryDate(targetExpiryDate: JsonField<LocalDate>) = apply {
                 this.targetExpiryDate = targetExpiryDate
             }
 
@@ -1588,7 +2099,7 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double?) = apply { this.amount = amount }
+            fun amount(amount: Double?) = amount(JsonField.ofNullable(amount))
 
             /**
              * The number of credits to effect. Note that this is required for increment, decrement,
@@ -1603,11 +2114,17 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun amount(amount: Optional<Double>) = amount(amount.orElse(null) as Double?)
 
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
             /**
              * The ID of the block affected by an expiration_change, used to differentiate between
              * multiple blocks with the same `expiry_date`.
              */
-            fun blockId(blockId: String?) = apply { this.blockId = blockId }
+            fun blockId(blockId: String?) = blockId(JsonField.ofNullable(blockId))
 
             /**
              * The ID of the block affected by an expiration_change, used to differentiate between
@@ -1615,11 +2132,17 @@ constructor(
              */
             fun blockId(blockId: Optional<String>) = blockId(blockId.orElse(null))
 
+            /**
+             * The ID of the block affected by an expiration_change, used to differentiate between
+             * multiple blocks with the same `expiry_date`.
+             */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1627,12 +2150,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1641,12 +2170,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1655,6 +2193,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1677,7 +2222,7 @@ constructor(
             fun build(): AddExpirationChangeCreditLedgerEntryRequestParams =
                 AddExpirationChangeCreditLedgerEntryRequestParams(
                     checkNotNull(entryType) { "`entryType` is required but was not set" },
-                    expiryDate,
+                    checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
                     checkNotNull(targetExpiryDate) {
                         "`targetExpiryDate` is required but was not set"
                     },
@@ -1758,6 +2303,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1838,13 +2391,27 @@ constructor(
     class AddVoidCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("block_id") private val blockId: String,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("void_reason") private val voidReason: VoidReason?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        private val voidReason: JsonField<VoidReason> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -1853,18 +2420,56 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
 
         /** The ID of the block to void. */
-        @JsonProperty("block_id") fun blockId(): String = blockId
+        fun blockId(): String = blockId.getRequired("block_id")
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** Can only be specified when `entry_type=void`. The reason for the void. */
+        fun voidReason(): Optional<VoidReason> =
+            Optional.ofNullable(voidReason.getNullable("void_reason"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
+
+        /** The ID of the block to void. */
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1872,23 +2477,40 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /** Can only be specified when `entry_type=void`. The reason for the void. */
         @JsonProperty("void_reason")
-        fun voidReason(): Optional<VoidReason> = Optional.ofNullable(voidReason)
+        @ExcludeMissing
+        fun _voidReason(): JsonField<VoidReason> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddVoidCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                blockId()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                voidReason()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1898,13 +2520,13 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
-            private var voidReason: VoidReason? = null
+            private var amount: JsonField<Double>? = null
+            private var blockId: JsonField<String>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var voidReason: JsonField<VoidReason> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1926,18 +2548,29 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
+
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
 
             /** The ID of the block to void. */
-            fun blockId(blockId: String) = apply { this.blockId = blockId }
+            fun blockId(blockId: String) = blockId(JsonField.of(blockId))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /** The ID of the block to void. */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1945,12 +2578,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1959,12 +2598,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1973,12 +2621,24 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /** Can only be specified when `entry_type=void`. The reason for the void. */
-            fun voidReason(voidReason: VoidReason?) = apply { this.voidReason = voidReason }
+            fun voidReason(voidReason: VoidReason?) = voidReason(JsonField.ofNullable(voidReason))
 
             /** Can only be specified when `entry_type=void`. The reason for the void. */
             fun voidReason(voidReason: Optional<VoidReason>) = voidReason(voidReason.orElse(null))
 
+            /** Can only be specified when `entry_type=void`. The reason for the void. */
+            fun voidReason(voidReason: JsonField<VoidReason>) = apply {
+                this.voidReason = voidReason
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2079,6 +2739,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2210,12 +2878,24 @@ constructor(
     class AddAmendmentCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("block_id") private val blockId: String,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -2224,18 +2904,52 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement or
          * void operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
+
+        /** The ID of the block to reverse a decrement from. */
+        fun blockId(): String = blockId.getRequired("block_id")
+
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement or
+         * void operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
         /** The ID of the block to reverse a decrement from. */
-        @JsonProperty("block_id") fun blockId(): String = blockId
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -2243,19 +2957,34 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddAmendmentCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                blockId()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2265,12 +2994,12 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var amount: JsonField<Double>? = null
+            private var blockId: JsonField<String>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2292,18 +3021,29 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement
              * or void operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
+
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement
+             * or void operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
 
             /** The ID of the block to reverse a decrement from. */
-            fun blockId(blockId: String) = apply { this.blockId = blockId }
+            fun blockId(blockId: String) = blockId(JsonField.of(blockId))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /** The ID of the block to reverse a decrement from. */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -2311,12 +3051,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -2325,12 +3071,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -2339,6 +3094,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2438,6 +3200,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdResponse.kt
index aeba2f02..3389f9a5 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryByExternalIdResponse.kt
@@ -453,38 +453,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -520,19 +534,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -581,7 +595,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -652,19 +668,23 @@ private constructor(
 
             fun build(): IncrementLedgerEntry =
                 IncrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -694,13 +714,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -726,9 +748,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -743,14 +765,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -780,9 +809,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -824,11 +855,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -853,8 +884,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -868,8 +899,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -899,8 +933,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1225,44 +1261,58 @@ private constructor(
 
         fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("event_id") @ExcludeMissing fun _eventId() = eventId
+        @JsonProperty("event_id") @ExcludeMissing fun _eventId(): JsonField<String> = eventId
 
-        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId() = invoiceId
+        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1301,19 +1351,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var eventId: JsonField<String> = JsonMissing.of()
             private var invoiceId: JsonField<String> = JsonMissing.of()
             private var priceId: JsonField<String> = JsonMissing.of()
@@ -1368,7 +1418,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -1418,15 +1470,21 @@ private constructor(
                 this.startingBalance = startingBalance
             }
 
-            fun eventId(eventId: String) = eventId(JsonField.of(eventId))
+            fun eventId(eventId: String?) = eventId(JsonField.ofNullable(eventId))
+
+            fun eventId(eventId: Optional<String>) = eventId(eventId.orElse(null))
 
             fun eventId(eventId: JsonField<String>) = apply { this.eventId = eventId }
 
-            fun invoiceId(invoiceId: String) = invoiceId(JsonField.of(invoiceId))
+            fun invoiceId(invoiceId: String?) = invoiceId(JsonField.ofNullable(invoiceId))
+
+            fun invoiceId(invoiceId: Optional<String>) = invoiceId(invoiceId.orElse(null))
 
             fun invoiceId(invoiceId: JsonField<String>) = apply { this.invoiceId = invoiceId }
 
-            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
+
+            fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
             fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
 
@@ -1451,19 +1509,23 @@ private constructor(
 
             fun build(): DecrementLedgerEntry =
                 DecrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     eventId,
                     invoiceId,
                     priceId,
@@ -1496,13 +1558,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1528,9 +1592,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1545,14 +1609,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -1582,9 +1653,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1626,11 +1699,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1655,8 +1728,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1670,8 +1743,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -1701,8 +1777,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2018,42 +2096,56 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2090,20 +2182,20 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2154,7 +2246,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2197,8 +2291,11 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime) =
-                newBlockExpiryDate(JsonField.of(newBlockExpiryDate))
+            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime?) =
+                newBlockExpiryDate(JsonField.ofNullable(newBlockExpiryDate))
+
+            fun newBlockExpiryDate(newBlockExpiryDate: Optional<OffsetDateTime>) =
+                newBlockExpiryDate(newBlockExpiryDate.orElse(null))
 
             fun newBlockExpiryDate(newBlockExpiryDate: JsonField<OffsetDateTime>) = apply {
                 this.newBlockExpiryDate = newBlockExpiryDate
@@ -2232,20 +2329,26 @@ private constructor(
 
             fun build(): ExpirationChangeLedgerEntry =
                 ExpirationChangeLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2275,13 +2378,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2307,9 +2412,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2324,14 +2429,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -2361,9 +2473,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2405,11 +2519,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2434,8 +2548,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2449,8 +2563,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -2480,8 +2597,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2791,38 +2910,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2858,19 +2991,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2920,7 +3053,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2991,19 +3126,23 @@ private constructor(
 
             fun build(): CreditBlockExpiryLedgerEntry =
                 CreditBlockExpiryLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3033,13 +3172,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3065,9 +3206,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3082,14 +3223,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3119,9 +3267,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3163,11 +3313,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3192,8 +3342,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3207,8 +3357,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -3238,8 +3391,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3560,42 +3715,60 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3633,21 +3806,21 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3698,7 +3871,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -3752,7 +3927,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -3777,21 +3954,25 @@ private constructor(
 
             fun build(): VoidLedgerEntry =
                 VoidLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3821,13 +4002,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3853,9 +4036,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3870,14 +4053,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3907,9 +4097,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3951,11 +4143,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3980,8 +4172,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3995,8 +4187,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4026,8 +4221,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4354,46 +4551,64 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4432,22 +4647,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4499,7 +4714,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -4560,7 +4777,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -4585,22 +4804,28 @@ private constructor(
 
             fun build(): VoidInitiatedLedgerEntry =
                 VoidInitiatedLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4630,13 +4855,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4662,9 +4889,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4679,14 +4906,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -4716,9 +4950,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4760,11 +4996,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4789,8 +5025,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4804,8 +5040,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4835,8 +5074,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5146,38 +5387,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5213,19 +5468,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5274,7 +5529,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -5345,19 +5602,23 @@ private constructor(
 
             fun build(): AmendmentLedgerEntry =
                 AmendmentLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5387,13 +5648,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5419,9 +5682,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5436,14 +5699,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -5473,9 +5743,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5517,11 +5789,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5546,8 +5818,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5561,8 +5833,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -5592,8 +5867,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryParams.kt
index 23109e67..03cff2f9 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -32,6 +33,108 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint allows you to create a new ledger entry for a specified customer's balance. This
+ * can be used to increment balance, deduct credits, and change the expiry date of existing credits.
+ *
+ * ## Effects of adding a ledger entry
+ * 1. After calling this endpoint, [Fetch Credit Balance](fetch-customer-credits) will return a
+ *    credit block that represents the changes (i.e. balance changes or transfers).
+ * 2. A ledger entry will be added to the credits ledger for this customer, and therefore returned
+ *    in the [View Credits Ledger](fetch-customer-credits-ledger) response as well as serialized in
+ *    the response to this request. In the case of deductions without a specified block, multiple
+ *    ledger entries may be created if the deduction spans credit blocks.
+ * 3. If `invoice_settings` is specified, an invoice will be created that reflects the cost of the
+ *    credits (based on `amount` and `per_unit_cost_basis`).
+ *
+ * ## Adding credits
+ *
+ * Adding credits is done by creating an entry of type `increment`. This requires the caller to
+ * specify a number of credits as well as an optional expiry date in `YYYY-MM-DD` format. Orb also
+ * recommends specifying a description to assist with auditing. When adding credits, the caller can
+ * also specify a cost basis per-credit, to indicate how much in USD a customer paid for a single
+ * credit in a block. This can later be used for revenue recognition.
+ *
+ * The following snippet illustrates a sample request body to increment credits which will expire in
+ * January of 2022.
+ *
+ * ```json
+ * {
+ *   "entry_type": "increment",
+ *   "amount": 100,
+ *   "expiry_date": "2022-12-28",
+ *   "per_unit_cost_basis": "0.20",
+ *   "description": "Purchased 100 credits"
+ * }
+ * ```
+ *
+ * Note that by default, Orb will always first increment any _negative_ balance in existing blocks
+ * before adding the remaining amount to the desired credit block.
+ *
+ * ### Invoicing for credits
+ *
+ * By default, Orb manipulates the credit ledger but does not charge for credits. However, if you
+ * pass `invoice_settings` in the body of this request, Orb will also generate a one-off invoice for
+ * the customer for the credits pre-purchase. Note that you _must_ provide the
+ * `per_unit_cost_basis`, since the total charges on the invoice are calculated by multiplying the
+ * cost basis with the number of credit units added.
+ *
+ * ## Deducting Credits
+ *
+ * Orb allows you to deduct credits from a customer by creating an entry of type `decrement`. Orb
+ * matches the algorithm for automatic deductions for determining which credit blocks to decrement
+ * from. In the case that the deduction leads to multiple ledger entries, the response from this
+ * endpoint will be the final deduction. Orb also optionally allows specifying a description to
+ * assist with auditing.
+ *
+ * The following snippet illustrates a sample request body to decrement credits.
+ *
+ * ```json
+ * {
+ *   "entry_type": "decrement",
+ *   "amount": 20,
+ *   "description": "Removing excess credits"
+ * }
+ * ```
+ *
+ * ## Changing credits expiry
+ *
+ * If you'd like to change when existing credits expire, you should create a ledger entry of type
+ * `expiration_change`. For this entry, the required parameter `expiry_date` identifies the
+ * _originating_ block, and the required parameter `target_expiry_date` identifies when the
+ * transferred credits should now expire. A new credit block will be created with expiry date
+ * `target_expiry_date`, with the same cost basis data as the original credit block, if present.
+ *
+ * Note that the balance of the block with the given `expiry_date` must be at least equal to the
+ * desired transfer amount determined by the `amount` parameter.
+ *
+ * The following snippet illustrates a sample request body to extend the expiration date of credits
+ * by one year:
+ * ```json
+ * {
+ *   "entry_type": "expiration_change",
+ *   "amount": 10,
+ *   "expiry_date": "2022-12-28",
+ *   "block_id": "UiUhFWeLHPrBY4Ad",
+ *   "target_expiry_date": "2023-12-28",
+ *   "description": "Extending credit validity"
+ * }
+ * ```
+ *
+ * ## Voiding credits
+ *
+ * If you'd like to void a credit block, create a ledger entry of type `void`. For this entry,
+ * `block_id` is required to identify the block, and `amount` indicates how many credits to void, up
+ * to the block's initial balance. Pass in a `void_reason` of `refund` if the void is due to a
+ * refund.
+ *
+ * ## Amendment
+ *
+ * If you'd like to undo a decrement on a credit block, create a ledger entry of type `amendment`.
+ * For this entry, `block_id` is required to identify the block that was originally decremented
+ * from, and `amount` indicates how many credits to return to the customer, up to the block's
+ * initial balance.
+ */
 class CustomerCreditLedgerCreateEntryParams
 constructor(
     private val customerId: String,
@@ -595,15 +698,33 @@ constructor(
     class AddIncrementCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("effective_date") private val effectiveDate: OffsetDateTime?,
-        @JsonProperty("expiry_date") private val expiryDate: OffsetDateTime?,
-        @JsonProperty("invoice_settings") private val invoiceSettings: InvoiceSettings?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("per_unit_cost_basis") private val perUnitCostBasis: String?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("effective_date")
+        @ExcludeMissing
+        private val effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("expiry_date")
+        @ExcludeMissing
+        private val expiryDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        private val invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        private val perUnitCostBasis: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -612,15 +733,72 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
+
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * An ISO 8601 format date that denotes when this credit balance should become available for
+         * use.
+         */
+        fun effectiveDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(effectiveDate.getNullable("effective_date"))
+
+        /** An ISO 8601 format date that denotes when this credit balance should expire. */
+        fun expiryDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(expiryDate.getNullable("expiry_date"))
+
+        /**
+         * Passing `invoice_settings` automatically generates an invoice for the newly added
+         * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as the
+         * calculation of the invoice total is done on that basis.
+         */
+        fun invoiceSettings(): Optional<InvoiceSettings> =
+            Optional.ofNullable(invoiceSettings.getNullable("invoice_settings"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * Can only be specified when entry_type=increment. How much, in the customer's currency, a
+         * customer paid for a single credit in this block
+         */
+        fun perUnitCostBasis(): Optional<String> =
+            Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -628,18 +806,21 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * An ISO 8601 format date that denotes when this credit balance should become available for
          * use.
          */
         @JsonProperty("effective_date")
-        fun effectiveDate(): Optional<OffsetDateTime> = Optional.ofNullable(effectiveDate)
+        @ExcludeMissing
+        fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
         /** An ISO 8601 format date that denotes when this credit balance should expire. */
         @JsonProperty("expiry_date")
-        fun expiryDate(): Optional<OffsetDateTime> = Optional.ofNullable(expiryDate)
+        @ExcludeMissing
+        fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
         /**
          * Passing `invoice_settings` automatically generates an invoice for the newly added
@@ -647,26 +828,45 @@ constructor(
          * calculation of the invoice total is done on that basis.
          */
         @JsonProperty("invoice_settings")
-        fun invoiceSettings(): Optional<InvoiceSettings> = Optional.ofNullable(invoiceSettings)
+        @ExcludeMissing
+        fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * Can only be specified when entry_type=increment. How much, in the customer's currency, a
          * customer paid for a single credit in this block
          */
         @JsonProperty("per_unit_cost_basis")
-        fun perUnitCostBasis(): Optional<String> = Optional.ofNullable(perUnitCostBasis)
+        @ExcludeMissing
+        fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddIncrementCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                entryType()
+                currency()
+                description()
+                effectiveDate()
+                expiryDate()
+                invoiceSettings().map { it.validate() }
+                metadata().map { it.validate() }
+                perUnitCostBasis()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -676,15 +876,15 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var effectiveDate: OffsetDateTime? = null
-            private var expiryDate: OffsetDateTime? = null
-            private var invoiceSettings: InvoiceSettings? = null
-            private var metadata: Metadata? = null
-            private var perUnitCostBasis: String? = null
+            private var amount: JsonField<Double>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -709,15 +909,23 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -725,12 +933,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -739,13 +953,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * An ISO 8601 format date that denotes when this credit balance should become available
              * for use.
              */
-            fun effectiveDate(effectiveDate: OffsetDateTime?) = apply {
-                this.effectiveDate = effectiveDate
-            }
+            fun effectiveDate(effectiveDate: OffsetDateTime?) =
+                effectiveDate(JsonField.ofNullable(effectiveDate))
 
             /**
              * An ISO 8601 format date that denotes when this credit balance should become available
@@ -754,21 +976,34 @@ constructor(
             fun effectiveDate(effectiveDate: Optional<OffsetDateTime>) =
                 effectiveDate(effectiveDate.orElse(null))
 
+            /**
+             * An ISO 8601 format date that denotes when this credit balance should become available
+             * for use.
+             */
+            fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
+                this.effectiveDate = effectiveDate
+            }
+
             /** An ISO 8601 format date that denotes when this credit balance should expire. */
-            fun expiryDate(expiryDate: OffsetDateTime?) = apply { this.expiryDate = expiryDate }
+            fun expiryDate(expiryDate: OffsetDateTime?) =
+                expiryDate(JsonField.ofNullable(expiryDate))
 
             /** An ISO 8601 format date that denotes when this credit balance should expire. */
             fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
                 expiryDate(expiryDate.orElse(null))
 
+            /** An ISO 8601 format date that denotes when this credit balance should expire. */
+            fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
+                this.expiryDate = expiryDate
+            }
+
             /**
              * Passing `invoice_settings` automatically generates an invoice for the newly added
              * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as
              * the calculation of the invoice total is done on that basis.
              */
-            fun invoiceSettings(invoiceSettings: InvoiceSettings?) = apply {
-                this.invoiceSettings = invoiceSettings
-            }
+            fun invoiceSettings(invoiceSettings: InvoiceSettings?) =
+                invoiceSettings(JsonField.ofNullable(invoiceSettings))
 
             /**
              * Passing `invoice_settings` automatically generates an invoice for the newly added
@@ -778,12 +1013,21 @@ constructor(
             fun invoiceSettings(invoiceSettings: Optional<InvoiceSettings>) =
                 invoiceSettings(invoiceSettings.orElse(null))
 
+            /**
+             * Passing `invoice_settings` automatically generates an invoice for the newly added
+             * credits. If `invoice_settings` is passed, you must specify per_unit_cost_basis, as
+             * the calculation of the invoice total is done on that basis.
+             */
+            fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
+                this.invoiceSettings = invoiceSettings
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -792,13 +1036,19 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * Can only be specified when entry_type=increment. How much, in the customer's
              * currency, a customer paid for a single credit in this block
              */
-            fun perUnitCostBasis(perUnitCostBasis: String?) = apply {
-                this.perUnitCostBasis = perUnitCostBasis
-            }
+            fun perUnitCostBasis(perUnitCostBasis: String?) =
+                perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
 
             /**
              * Can only be specified when entry_type=increment. How much, in the customer's
@@ -807,6 +1057,14 @@ constructor(
             fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
                 perUnitCostBasis(perUnitCostBasis.orElse(null))
 
+            /**
+             * Can only be specified when entry_type=increment. How much, in the customer's
+             * currency, a customer paid for a single credit in this block
+             */
+            fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
+                this.perUnitCostBasis = perUnitCostBasis
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -901,11 +1159,18 @@ constructor(
         class InvoiceSettings
         @JsonCreator
         private constructor(
-            @JsonProperty("auto_collection") private val autoCollection: Boolean,
-            @JsonProperty("net_terms") private val netTerms: Long,
-            @JsonProperty("memo") private val memo: String?,
+            @JsonProperty("auto_collection")
+            @ExcludeMissing
+            private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("net_terms")
+            @ExcludeMissing
+            private val netTerms: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("memo")
+            @ExcludeMissing
+            private val memo: JsonField<String> = JsonMissing.of(),
             @JsonProperty("require_successful_payment")
-            private val requireSuccessfulPayment: Boolean?,
+            @ExcludeMissing
+            private val requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
@@ -914,29 +1179,67 @@ constructor(
              * Whether the credits purchase invoice should auto collect with the customer's saved
              * payment method.
              */
-            @JsonProperty("auto_collection") fun autoCollection(): Boolean = autoCollection
+            fun autoCollection(): Boolean = autoCollection.getRequired("auto_collection")
 
             /**
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0.
              */
-            @JsonProperty("net_terms") fun netTerms(): Long = netTerms
+            fun netTerms(): Long = netTerms.getRequired("net_terms")
 
             /** An optional memo to display on the invoice. */
-            @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+            fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
 
             /**
              * If true, the new credit block will require that the corresponding invoice is paid
              * before it can be drawn down from.
              */
-            @JsonProperty("require_successful_payment")
             fun requireSuccessfulPayment(): Optional<Boolean> =
-                Optional.ofNullable(requireSuccessfulPayment)
+                Optional.ofNullable(
+                    requireSuccessfulPayment.getNullable("require_successful_payment")
+                )
+
+            /**
+             * Whether the credits purchase invoice should auto collect with the customer's saved
+             * payment method.
+             */
+            @JsonProperty("auto_collection")
+            @ExcludeMissing
+            fun _autoCollection(): JsonField<Boolean> = autoCollection
+
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0.
+             */
+            @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
+
+            /** An optional memo to display on the invoice. */
+            @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
+
+            /**
+             * If true, the new credit block will require that the corresponding invoice is paid
+             * before it can be drawn down from.
+             */
+            @JsonProperty("require_successful_payment")
+            @ExcludeMissing
+            fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoiceSettings = apply {
+                if (!validated) {
+                    autoCollection()
+                    netTerms()
+                    memo()
+                    requireSuccessfulPayment()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -946,10 +1249,10 @@ constructor(
 
             class Builder {
 
-                private var autoCollection: Boolean? = null
-                private var netTerms: Long? = null
-                private var memo: String? = null
-                private var requireSuccessfulPayment: Boolean? = null
+                private var autoCollection: JsonField<Boolean>? = null
+                private var netTerms: JsonField<Long>? = null
+                private var memo: JsonField<String> = JsonMissing.of()
+                private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -965,7 +1268,14 @@ constructor(
                  * Whether the credits purchase invoice should auto collect with the customer's
                  * saved payment method.
                  */
-                fun autoCollection(autoCollection: Boolean) = apply {
+                fun autoCollection(autoCollection: Boolean) =
+                    autoCollection(JsonField.of(autoCollection))
+
+                /**
+                 * Whether the credits purchase invoice should auto collect with the customer's
+                 * saved payment method.
+                 */
+                fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
                     this.autoCollection = autoCollection
                 }
 
@@ -974,36 +1284,38 @@ constructor(
                  * date for the invoice. If you intend the invoice to be due on issue, set this
                  * to 0.
                  */
-                fun netTerms(netTerms: Long) = apply { this.netTerms = netTerms }
+                fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+
+                /**
+                 * The net terms determines the difference between the invoice date and the issue
+                 * date for the invoice. If you intend the invoice to be due on issue, set this
+                 * to 0.
+                 */
+                fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
                 /** An optional memo to display on the invoice. */
-                fun memo(memo: String?) = apply { this.memo = memo }
+                fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
                 /** An optional memo to display on the invoice. */
                 fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
-                /**
-                 * If true, the new credit block will require that the corresponding invoice is paid
-                 * before it can be drawn down from.
-                 */
-                fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean?) = apply {
-                    this.requireSuccessfulPayment = requireSuccessfulPayment
-                }
+                /** An optional memo to display on the invoice. */
+                fun memo(memo: JsonField<String>) = apply { this.memo = memo }
 
                 /**
                  * If true, the new credit block will require that the corresponding invoice is paid
                  * before it can be drawn down from.
                  */
                 fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean) =
-                    requireSuccessfulPayment(requireSuccessfulPayment as Boolean?)
+                    requireSuccessfulPayment(JsonField.of(requireSuccessfulPayment))
 
                 /**
                  * If true, the new credit block will require that the corresponding invoice is paid
                  * before it can be drawn down from.
                  */
-                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                fun requireSuccessfulPayment(requireSuccessfulPayment: Optional<Boolean>) =
-                    requireSuccessfulPayment(requireSuccessfulPayment.orElse(null) as Boolean?)
+                fun requireSuccessfulPayment(requireSuccessfulPayment: JsonField<Boolean>) = apply {
+                    this.requireSuccessfulPayment = requireSuccessfulPayment
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1074,6 +1386,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1154,11 +1474,21 @@ constructor(
     class AddDecrementCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -1167,15 +1497,46 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1183,19 +1544,33 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddDecrementCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1205,11 +1580,11 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var amount: JsonField<Double>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1230,15 +1605,23 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1246,12 +1629,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1260,12 +1649,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1274,6 +1672,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1372,6 +1777,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1452,47 +1865,113 @@ constructor(
     class AddExpirationChangeCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("expiry_date") private val expiryDate: OffsetDateTime?,
-        @JsonProperty("target_expiry_date") private val targetExpiryDate: LocalDate,
-        @JsonProperty("amount") private val amount: Double?,
-        @JsonProperty("block_id") private val blockId: String?,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("expiry_date")
+        @ExcludeMissing
+        private val expiryDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("target_expiry_date")
+        @ExcludeMissing
+        private val targetExpiryDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /** An ISO 8601 format date that identifies the origination credit block to expire */
+        fun expiryDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(expiryDate.getNullable("expiry_date"))
+
+        /**
+         * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting when
+         * credits transferred (as part of a partial block expiration) should expire.
+         */
+        fun targetExpiryDate(): LocalDate = targetExpiryDate.getRequired("target_expiry_date")
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        fun amount(): Optional<Double> = Optional.ofNullable(amount.getNullable("amount"))
+
+        /**
+         * The ID of the block affected by an expiration_change, used to differentiate between
+         * multiple blocks with the same `expiry_date`.
+         */
+        fun blockId(): Optional<String> = Optional.ofNullable(blockId.getNullable("block_id"))
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /** An ISO 8601 format date that identifies the origination credit block to expire */
         @JsonProperty("expiry_date")
-        fun expiryDate(): Optional<OffsetDateTime> = Optional.ofNullable(expiryDate)
+        @ExcludeMissing
+        fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
         /**
          * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting when
          * credits transferred (as part of a partial block expiration) should expire.
          */
-        @JsonProperty("target_expiry_date") fun targetExpiryDate(): LocalDate = targetExpiryDate
+        @JsonProperty("target_expiry_date")
+        @ExcludeMissing
+        fun _targetExpiryDate(): JsonField<LocalDate> = targetExpiryDate
 
         /**
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Optional<Double> = Optional.ofNullable(amount)
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
         /**
          * The ID of the block affected by an expiration_change, used to differentiate between
          * multiple blocks with the same `expiry_date`.
          */
-        @JsonProperty("block_id") fun blockId(): Optional<String> = Optional.ofNullable(blockId)
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1500,19 +1979,36 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddExpirationChangeCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                entryType()
+                expiryDate()
+                targetExpiryDate()
+                amount()
+                blockId()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1522,14 +2018,14 @@ constructor(
 
         class Builder {
 
-            private var entryType: EntryType? = null
-            private var expiryDate: OffsetDateTime? = null
-            private var targetExpiryDate: LocalDate? = null
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var expiryDate: JsonField<OffsetDateTime>? = null
+            private var targetExpiryDate: JsonField<LocalDate>? = null
+            private var amount: JsonField<Double> = JsonMissing.of()
+            private var blockId: JsonField<String> = JsonMissing.of()
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1551,20 +2047,35 @@ constructor(
                         .toMutableMap()
             }
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /** An ISO 8601 format date that identifies the origination credit block to expire */
-            fun expiryDate(expiryDate: OffsetDateTime?) = apply { this.expiryDate = expiryDate }
+            fun expiryDate(expiryDate: OffsetDateTime?) =
+                expiryDate(JsonField.ofNullable(expiryDate))
 
             /** An ISO 8601 format date that identifies the origination credit block to expire */
             fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
                 expiryDate(expiryDate.orElse(null))
 
+            /** An ISO 8601 format date that identifies the origination credit block to expire */
+            fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
+                this.expiryDate = expiryDate
+            }
+
+            /**
+             * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting
+             * when credits transferred (as part of a partial block expiration) should expire.
+             */
+            fun targetExpiryDate(targetExpiryDate: LocalDate) =
+                targetExpiryDate(JsonField.of(targetExpiryDate))
+
             /**
              * A future date (specified in YYYY-MM-DD format) used for expiration change, denoting
              * when credits transferred (as part of a partial block expiration) should expire.
              */
-            fun targetExpiryDate(targetExpiryDate: LocalDate) = apply {
+            fun targetExpiryDate(targetExpiryDate: JsonField<LocalDate>) = apply {
                 this.targetExpiryDate = targetExpiryDate
             }
 
@@ -1572,7 +2083,7 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double?) = apply { this.amount = amount }
+            fun amount(amount: Double?) = amount(JsonField.ofNullable(amount))
 
             /**
              * The number of credits to effect. Note that this is required for increment, decrement,
@@ -1587,11 +2098,17 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun amount(amount: Optional<Double>) = amount(amount.orElse(null) as Double?)
 
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
+
             /**
              * The ID of the block affected by an expiration_change, used to differentiate between
              * multiple blocks with the same `expiry_date`.
              */
-            fun blockId(blockId: String?) = apply { this.blockId = blockId }
+            fun blockId(blockId: String?) = blockId(JsonField.ofNullable(blockId))
 
             /**
              * The ID of the block affected by an expiration_change, used to differentiate between
@@ -1599,11 +2116,17 @@ constructor(
              */
             fun blockId(blockId: Optional<String>) = blockId(blockId.orElse(null))
 
+            /**
+             * The ID of the block affected by an expiration_change, used to differentiate between
+             * multiple blocks with the same `expiry_date`.
+             */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1611,12 +2134,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1625,12 +2154,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1639,6 +2177,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1661,7 +2206,7 @@ constructor(
             fun build(): AddExpirationChangeCreditLedgerEntryRequestParams =
                 AddExpirationChangeCreditLedgerEntryRequestParams(
                     checkNotNull(entryType) { "`entryType` is required but was not set" },
-                    expiryDate,
+                    checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
                     checkNotNull(targetExpiryDate) {
                         "`targetExpiryDate` is required but was not set"
                     },
@@ -1742,6 +2287,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1822,13 +2375,27 @@ constructor(
     class AddVoidCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("block_id") private val blockId: String,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("void_reason") private val voidReason: VoidReason?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        private val voidReason: JsonField<VoidReason> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -1837,18 +2404,56 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement,
          * void, or undo operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
 
         /** The ID of the block to void. */
-        @JsonProperty("block_id") fun blockId(): String = blockId
+        fun blockId(): String = blockId.getRequired("block_id")
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** Can only be specified when `entry_type=void`. The reason for the void. */
+        fun voidReason(): Optional<VoidReason> =
+            Optional.ofNullable(voidReason.getNullable("void_reason"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement,
+         * void, or undo operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
+
+        /** The ID of the block to void. */
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
+
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1856,23 +2461,40 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /** Can only be specified when `entry_type=void`. The reason for the void. */
         @JsonProperty("void_reason")
-        fun voidReason(): Optional<VoidReason> = Optional.ofNullable(voidReason)
+        @ExcludeMissing
+        fun _voidReason(): JsonField<VoidReason> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddVoidCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                blockId()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                voidReason()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1882,13 +2504,13 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
-            private var voidReason: VoidReason? = null
+            private var amount: JsonField<Double>? = null
+            private var blockId: JsonField<String>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var voidReason: JsonField<VoidReason> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1910,18 +2532,29 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement,
              * void, or undo operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
+
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement,
+             * void, or undo operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
 
             /** The ID of the block to void. */
-            fun blockId(blockId: String) = apply { this.blockId = blockId }
+            fun blockId(blockId: String) = blockId(JsonField.of(blockId))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /** The ID of the block to void. */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -1929,12 +2562,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -1943,12 +2582,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1957,12 +2605,24 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /** Can only be specified when `entry_type=void`. The reason for the void. */
-            fun voidReason(voidReason: VoidReason?) = apply { this.voidReason = voidReason }
+            fun voidReason(voidReason: VoidReason?) = voidReason(JsonField.ofNullable(voidReason))
 
             /** Can only be specified when `entry_type=void`. The reason for the void. */
             fun voidReason(voidReason: Optional<VoidReason>) = voidReason(voidReason.orElse(null))
 
+            /** Can only be specified when `entry_type=void`. The reason for the void. */
+            fun voidReason(voidReason: JsonField<VoidReason>) = apply {
+                this.voidReason = voidReason
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2063,6 +2723,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2194,12 +2862,24 @@ constructor(
     class AddAmendmentCreditLedgerEntryRequestParams
     @JsonCreator
     private constructor(
-        @JsonProperty("amount") private val amount: Double,
-        @JsonProperty("block_id") private val blockId: String,
-        @JsonProperty("entry_type") private val entryType: EntryType,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("block_id")
+        @ExcludeMissing
+        private val blockId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        private val entryType: JsonField<EntryType> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -2208,18 +2888,52 @@ constructor(
          * The number of credits to effect. Note that this is required for increment, decrement or
          * void operations.
          */
-        @JsonProperty("amount") fun amount(): Double = amount
+        fun amount(): Double = amount.getRequired("amount")
+
+        /** The ID of the block to reverse a decrement from. */
+        fun blockId(): String = blockId.getRequired("block_id")
+
+        fun entryType(): EntryType = entryType.getRequired("entry_type")
+
+        /**
+         * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /**
+         * Optional metadata that can be specified when adding ledger results via the API. For
+         * example, this can be used to note an increment refers to trial credits, or for noting
+         * corrections as a result of an incident, etc.
+         */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The number of credits to effect. Note that this is required for increment, decrement or
+         * void operations.
+         */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
         /** The ID of the block to reverse a decrement from. */
-        @JsonProperty("block_id") fun blockId(): String = blockId
+        @JsonProperty("block_id") @ExcludeMissing fun _blockId(): JsonField<String> = blockId
 
-        @JsonProperty("entry_type") fun entryType(): EntryType = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         /**
          * The currency or custom pricing unit to use for this ledger entry. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional metadata that can be specified when adding ledger results via the API. For
@@ -2227,19 +2941,34 @@ constructor(
          * corrections as a result of an incident, etc.
          */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddAmendmentCreditLedgerEntryRequestParams = apply {
+            if (!validated) {
+                amount()
+                blockId()
+                entryType()
+                currency()
+                description()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2249,12 +2978,12 @@ constructor(
 
         class Builder {
 
-            private var amount: Double? = null
-            private var blockId: String? = null
-            private var entryType: EntryType? = null
-            private var currency: String? = null
-            private var description: String? = null
-            private var metadata: Metadata? = null
+            private var amount: JsonField<Double>? = null
+            private var blockId: JsonField<String>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var description: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2276,18 +3005,29 @@ constructor(
              * The number of credits to effect. Note that this is required for increment, decrement
              * or void operations.
              */
-            fun amount(amount: Double) = apply { this.amount = amount }
+            fun amount(amount: Double) = amount(JsonField.of(amount))
+
+            /**
+             * The number of credits to effect. Note that this is required for increment, decrement
+             * or void operations.
+             */
+            fun amount(amount: JsonField<Double>) = apply { this.amount = amount }
 
             /** The ID of the block to reverse a decrement from. */
-            fun blockId(blockId: String) = apply { this.blockId = blockId }
+            fun blockId(blockId: String) = blockId(JsonField.of(blockId))
 
-            fun entryType(entryType: EntryType) = apply { this.entryType = entryType }
+            /** The ID of the block to reverse a decrement from. */
+            fun blockId(blockId: JsonField<String>) = apply { this.blockId = blockId }
+
+            fun entryType(entryType: EntryType) = entryType(JsonField.of(entryType))
+
+            fun entryType(entryType: JsonField<EntryType>) = apply { this.entryType = entryType }
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
              * real-world currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * The currency or custom pricing unit to use for this ledger entry. If this is a
@@ -2295,12 +3035,18 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * The currency or custom pricing unit to use for this ledger entry. If this is a
+             * real-world currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
              * example, this can be used to note an increment refers to trial credits, or for noting
              * corrections as a result of an incident, etc.
              */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /**
              * Optional metadata that can be specified when adding ledger results via the API. For
@@ -2309,12 +3055,21 @@ constructor(
              */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /**
+             * Optional metadata that can be specified when adding ledger results via the API. For
+             * example, this can be used to note an increment refers to trial credits, or for noting
+             * corrections as a result of an incident, etc.
+             */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -2323,6 +3078,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2422,6 +3184,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryResponse.kt
index 2ff60595..c33a94e1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerCreateEntryResponse.kt
@@ -440,38 +440,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -507,19 +521,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -568,7 +582,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -639,19 +655,23 @@ private constructor(
 
             fun build(): IncrementLedgerEntry =
                 IncrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -681,13 +701,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -713,9 +735,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -730,14 +752,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -767,9 +796,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -811,11 +842,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -840,8 +871,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -855,8 +886,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -886,8 +920,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1212,44 +1248,58 @@ private constructor(
 
         fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("event_id") @ExcludeMissing fun _eventId() = eventId
+        @JsonProperty("event_id") @ExcludeMissing fun _eventId(): JsonField<String> = eventId
 
-        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId() = invoiceId
+        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1288,19 +1338,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var eventId: JsonField<String> = JsonMissing.of()
             private var invoiceId: JsonField<String> = JsonMissing.of()
             private var priceId: JsonField<String> = JsonMissing.of()
@@ -1355,7 +1405,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -1405,15 +1457,21 @@ private constructor(
                 this.startingBalance = startingBalance
             }
 
-            fun eventId(eventId: String) = eventId(JsonField.of(eventId))
+            fun eventId(eventId: String?) = eventId(JsonField.ofNullable(eventId))
+
+            fun eventId(eventId: Optional<String>) = eventId(eventId.orElse(null))
 
             fun eventId(eventId: JsonField<String>) = apply { this.eventId = eventId }
 
-            fun invoiceId(invoiceId: String) = invoiceId(JsonField.of(invoiceId))
+            fun invoiceId(invoiceId: String?) = invoiceId(JsonField.ofNullable(invoiceId))
+
+            fun invoiceId(invoiceId: Optional<String>) = invoiceId(invoiceId.orElse(null))
 
             fun invoiceId(invoiceId: JsonField<String>) = apply { this.invoiceId = invoiceId }
 
-            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
+
+            fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
             fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
 
@@ -1438,19 +1496,23 @@ private constructor(
 
             fun build(): DecrementLedgerEntry =
                 DecrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     eventId,
                     invoiceId,
                     priceId,
@@ -1483,13 +1545,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1515,9 +1579,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1532,14 +1596,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -1569,9 +1640,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1613,11 +1686,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1642,8 +1715,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1657,8 +1730,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -1688,8 +1764,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2005,42 +2083,56 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2077,20 +2169,20 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2141,7 +2233,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2184,8 +2278,11 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime) =
-                newBlockExpiryDate(JsonField.of(newBlockExpiryDate))
+            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime?) =
+                newBlockExpiryDate(JsonField.ofNullable(newBlockExpiryDate))
+
+            fun newBlockExpiryDate(newBlockExpiryDate: Optional<OffsetDateTime>) =
+                newBlockExpiryDate(newBlockExpiryDate.orElse(null))
 
             fun newBlockExpiryDate(newBlockExpiryDate: JsonField<OffsetDateTime>) = apply {
                 this.newBlockExpiryDate = newBlockExpiryDate
@@ -2219,20 +2316,26 @@ private constructor(
 
             fun build(): ExpirationChangeLedgerEntry =
                 ExpirationChangeLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2262,13 +2365,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2294,9 +2399,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2311,14 +2416,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -2348,9 +2460,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2392,11 +2506,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2421,8 +2535,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2436,8 +2550,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -2467,8 +2584,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2778,38 +2897,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2845,19 +2978,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2907,7 +3040,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2978,19 +3113,23 @@ private constructor(
 
             fun build(): CreditBlockExpiryLedgerEntry =
                 CreditBlockExpiryLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3020,13 +3159,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3052,9 +3193,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3069,14 +3210,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3106,9 +3254,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3150,11 +3300,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3179,8 +3329,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3194,8 +3344,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -3225,8 +3378,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3547,42 +3702,60 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3620,21 +3793,21 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3685,7 +3858,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -3739,7 +3914,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -3764,21 +3941,25 @@ private constructor(
 
             fun build(): VoidLedgerEntry =
                 VoidLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3808,13 +3989,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3840,9 +4023,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3857,14 +4040,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3894,9 +4084,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3938,11 +4130,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3967,8 +4159,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3982,8 +4174,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4013,8 +4208,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4341,46 +4538,64 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4419,22 +4634,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4486,7 +4701,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -4547,7 +4764,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -4572,22 +4791,28 @@ private constructor(
 
             fun build(): VoidInitiatedLedgerEntry =
                 VoidInitiatedLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4617,13 +4842,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4649,9 +4876,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4666,14 +4893,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -4703,9 +4937,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4747,11 +4983,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4776,8 +5012,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4791,8 +5027,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4822,8 +5061,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5133,38 +5374,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5200,19 +5455,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5261,7 +5516,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -5332,19 +5589,23 @@ private constructor(
 
             fun build(): AmendmentLedgerEntry =
                 AmendmentLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5374,13 +5635,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5406,9 +5669,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5423,14 +5686,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -5460,9 +5730,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5504,11 +5776,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5533,8 +5805,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5548,8 +5820,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -5579,8 +5854,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdParams.kt
index 668f951b..2bc4387d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdParams.kt
@@ -14,6 +14,84 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * The credits ledger provides _auditing_ functionality over Orb's credits system with a list of
+ * actions that have taken place to modify a customer's credit balance. This
+ * [paginated endpoint](../reference/pagination) lists these entries, starting from the most recent
+ * ledger entry.
+ *
+ * More details on using Orb's real-time credit feature are
+ * [here](../guides/product-catalog/prepurchase.md).
+ *
+ * There are four major types of modifications to credit balance, detailed below.
+ *
+ * ## Increment
+ *
+ * Credits (which optionally expire on a future date) can be added via the API ([Add Ledger
+ * Entry](create-ledger-entry)). The ledger entry for such an action will always contain the total
+ * eligible starting and ending balance for the customer at the time the entry was added to the
+ * ledger.
+ *
+ * ## Decrement
+ *
+ * Deductions can occur as a result of an API call to create a ledger entry (see
+ * [Add Ledger Entry](create-ledger-entry)), or automatically as a result of incurring usage. Both
+ * ledger entries present the `decrement` entry type.
+ *
+ * As usage for a customer is reported into Orb, credits may be deducted according to the customer's
+ * plan configuration. An automated deduction of this type will result in a ledger entry, also with
+ * a starting and ending balance. In order to provide better tracing capabilities for automatic
+ * deductions, Orb always associates each automatic deduction with the `event_id` at the time of
+ * ingestion, used to pinpoint _why_ credit deduction took place and to ensure that credits are
+ * never deducted without an associated usage event.
+ *
+ * By default, Orb uses an algorithm that automatically deducts from the _soonest expiring credit
+ * block_ first in order to ensure that all credits are utilized appropriately. As an example, if
+ * trial credits with an expiration date of 2 weeks from now are present for a customer, they will
+ * be used before any deductions take place from a non-expiring credit block.
+ *
+ * If there are multiple blocks with the same expiration date, Orb will deduct from the block with
+ * the _lower cost basis_ first (e.g. trial credits with a $0 cost basis before paid credits with a
+ * $5.00 cost basis).
+ *
+ * It's also possible for a single usage event's deduction to _span_ credit blocks. In this case,
+ * Orb will deduct from the next block, ending at the credit block which consists of unexpiring
+ * credits. Each of these deductions will lead to a _separate_ ledger entry, one per credit block
+ * that is deducted from. By default, the customer's total credit balance in Orb can be negative as
+ * a result of a decrement.
+ *
+ * ## Expiration change
+ *
+ * The expiry of credits can be changed as a result of the API (See
+ * [Add Ledger Entry](create-ledger-entry)). This will create a ledger entry that specifies the
+ * balance as well as the initial and target expiry dates.
+ *
+ * Note that for this entry type, `starting_balance` will equal `ending_balance`, and the `amount`
+ * represents the balance transferred. The credit block linked to the ledger entry is the source
+ * credit block from which there was an expiration change
+ *
+ * ## Credits expiry
+ *
+ * When a set of credits expire on pre-set expiration date, the customer's balance automatically
+ * reflects this change and adds an entry to the ledger indicating this event. Note that credit
+ * expiry should always happen close to a date boundary in the customer's timezone.
+ *
+ * ## Void initiated
+ *
+ * Credit blocks can be voided via the API. The `amount` on this entry corresponds to the number of
+ * credits that were remaining in the block at time of void. `void_reason` will be populated if the
+ * void is created with a reason.
+ *
+ * ## Void
+ *
+ * When a set of credits is voided, the customer's balance automatically reflects this change and
+ * adds an entry to the ledger indicating this event.
+ *
+ * ## Amendment
+ *
+ * When credits are added to a customer's balance as a result of a correction, this entry will be
+ * added to the ledger to indicate the adjustment of credits.
+ */
 class CustomerCreditLedgerListByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdResponse.kt
index 48b9960e..7ec6413b 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListByExternalIdResponse.kt
@@ -451,38 +451,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -518,19 +532,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -579,7 +593,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -650,19 +666,23 @@ private constructor(
 
             fun build(): IncrementLedgerEntry =
                 IncrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -692,13 +712,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -724,9 +746,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -741,14 +763,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -778,9 +807,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -822,11 +853,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -851,8 +882,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -866,8 +897,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -897,8 +931,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1223,44 +1259,58 @@ private constructor(
 
         fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("event_id") @ExcludeMissing fun _eventId() = eventId
+        @JsonProperty("event_id") @ExcludeMissing fun _eventId(): JsonField<String> = eventId
 
-        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId() = invoiceId
+        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1299,19 +1349,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var eventId: JsonField<String> = JsonMissing.of()
             private var invoiceId: JsonField<String> = JsonMissing.of()
             private var priceId: JsonField<String> = JsonMissing.of()
@@ -1366,7 +1416,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -1416,15 +1468,21 @@ private constructor(
                 this.startingBalance = startingBalance
             }
 
-            fun eventId(eventId: String) = eventId(JsonField.of(eventId))
+            fun eventId(eventId: String?) = eventId(JsonField.ofNullable(eventId))
+
+            fun eventId(eventId: Optional<String>) = eventId(eventId.orElse(null))
 
             fun eventId(eventId: JsonField<String>) = apply { this.eventId = eventId }
 
-            fun invoiceId(invoiceId: String) = invoiceId(JsonField.of(invoiceId))
+            fun invoiceId(invoiceId: String?) = invoiceId(JsonField.ofNullable(invoiceId))
+
+            fun invoiceId(invoiceId: Optional<String>) = invoiceId(invoiceId.orElse(null))
 
             fun invoiceId(invoiceId: JsonField<String>) = apply { this.invoiceId = invoiceId }
 
-            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
+
+            fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
             fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
 
@@ -1449,19 +1507,23 @@ private constructor(
 
             fun build(): DecrementLedgerEntry =
                 DecrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     eventId,
                     invoiceId,
                     priceId,
@@ -1494,13 +1556,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1526,9 +1590,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1543,14 +1607,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -1580,9 +1651,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1624,11 +1697,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1653,8 +1726,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1668,8 +1741,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -1699,8 +1775,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2016,42 +2094,56 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2088,20 +2180,20 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2152,7 +2244,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2195,8 +2289,11 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime) =
-                newBlockExpiryDate(JsonField.of(newBlockExpiryDate))
+            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime?) =
+                newBlockExpiryDate(JsonField.ofNullable(newBlockExpiryDate))
+
+            fun newBlockExpiryDate(newBlockExpiryDate: Optional<OffsetDateTime>) =
+                newBlockExpiryDate(newBlockExpiryDate.orElse(null))
 
             fun newBlockExpiryDate(newBlockExpiryDate: JsonField<OffsetDateTime>) = apply {
                 this.newBlockExpiryDate = newBlockExpiryDate
@@ -2230,20 +2327,26 @@ private constructor(
 
             fun build(): ExpirationChangeLedgerEntry =
                 ExpirationChangeLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2273,13 +2376,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2305,9 +2410,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2322,14 +2427,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -2359,9 +2471,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2403,11 +2517,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2432,8 +2546,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2447,8 +2561,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -2478,8 +2595,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2789,38 +2908,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2856,19 +2989,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2918,7 +3051,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2989,19 +3124,23 @@ private constructor(
 
             fun build(): CreditBlockExpiryLedgerEntry =
                 CreditBlockExpiryLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3031,13 +3170,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3063,9 +3204,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3080,14 +3221,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3117,9 +3265,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3161,11 +3311,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3190,8 +3340,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3205,8 +3355,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -3236,8 +3389,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3558,42 +3713,60 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3631,21 +3804,21 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3696,7 +3869,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -3750,7 +3925,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -3775,21 +3952,25 @@ private constructor(
 
             fun build(): VoidLedgerEntry =
                 VoidLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3819,13 +4000,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3851,9 +4034,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3868,14 +4051,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3905,9 +4095,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3949,11 +4141,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3978,8 +4170,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3993,8 +4185,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4024,8 +4219,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4352,46 +4549,64 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4430,22 +4645,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4497,7 +4712,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -4558,7 +4775,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -4583,22 +4802,28 @@ private constructor(
 
             fun build(): VoidInitiatedLedgerEntry =
                 VoidInitiatedLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4628,13 +4853,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4660,9 +4887,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4677,14 +4904,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -4714,9 +4948,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4758,11 +4994,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4787,8 +5023,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4802,8 +5038,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4833,8 +5072,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5144,38 +5385,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5211,19 +5466,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5272,7 +5527,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -5343,19 +5600,23 @@ private constructor(
 
             fun build(): AmendmentLedgerEntry =
                 AmendmentLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5385,13 +5646,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5417,9 +5680,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5434,14 +5697,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -5471,9 +5741,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5515,11 +5787,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5544,8 +5816,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5559,8 +5831,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -5590,8 +5865,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListParams.kt
index 5f8c9371..90f10db2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListParams.kt
@@ -14,6 +14,84 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * The credits ledger provides _auditing_ functionality over Orb's credits system with a list of
+ * actions that have taken place to modify a customer's credit balance. This
+ * [paginated endpoint](../reference/pagination) lists these entries, starting from the most recent
+ * ledger entry.
+ *
+ * More details on using Orb's real-time credit feature are
+ * [here](../guides/product-catalog/prepurchase.md).
+ *
+ * There are four major types of modifications to credit balance, detailed below.
+ *
+ * ## Increment
+ *
+ * Credits (which optionally expire on a future date) can be added via the API ([Add Ledger
+ * Entry](create-ledger-entry)). The ledger entry for such an action will always contain the total
+ * eligible starting and ending balance for the customer at the time the entry was added to the
+ * ledger.
+ *
+ * ## Decrement
+ *
+ * Deductions can occur as a result of an API call to create a ledger entry (see
+ * [Add Ledger Entry](create-ledger-entry)), or automatically as a result of incurring usage. Both
+ * ledger entries present the `decrement` entry type.
+ *
+ * As usage for a customer is reported into Orb, credits may be deducted according to the customer's
+ * plan configuration. An automated deduction of this type will result in a ledger entry, also with
+ * a starting and ending balance. In order to provide better tracing capabilities for automatic
+ * deductions, Orb always associates each automatic deduction with the `event_id` at the time of
+ * ingestion, used to pinpoint _why_ credit deduction took place and to ensure that credits are
+ * never deducted without an associated usage event.
+ *
+ * By default, Orb uses an algorithm that automatically deducts from the _soonest expiring credit
+ * block_ first in order to ensure that all credits are utilized appropriately. As an example, if
+ * trial credits with an expiration date of 2 weeks from now are present for a customer, they will
+ * be used before any deductions take place from a non-expiring credit block.
+ *
+ * If there are multiple blocks with the same expiration date, Orb will deduct from the block with
+ * the _lower cost basis_ first (e.g. trial credits with a $0 cost basis before paid credits with a
+ * $5.00 cost basis).
+ *
+ * It's also possible for a single usage event's deduction to _span_ credit blocks. In this case,
+ * Orb will deduct from the next block, ending at the credit block which consists of unexpiring
+ * credits. Each of these deductions will lead to a _separate_ ledger entry, one per credit block
+ * that is deducted from. By default, the customer's total credit balance in Orb can be negative as
+ * a result of a decrement.
+ *
+ * ## Expiration change
+ *
+ * The expiry of credits can be changed as a result of the API (See
+ * [Add Ledger Entry](create-ledger-entry)). This will create a ledger entry that specifies the
+ * balance as well as the initial and target expiry dates.
+ *
+ * Note that for this entry type, `starting_balance` will equal `ending_balance`, and the `amount`
+ * represents the balance transferred. The credit block linked to the ledger entry is the source
+ * credit block from which there was an expiration change
+ *
+ * ## Credits expiry
+ *
+ * When a set of credits expire on pre-set expiration date, the customer's balance automatically
+ * reflects this change and adds an entry to the ledger indicating this event. Note that credit
+ * expiry should always happen close to a date boundary in the customer's timezone.
+ *
+ * ## Void initiated
+ *
+ * Credit blocks can be voided via the API. The `amount` on this entry corresponds to the number of
+ * credits that were remaining in the block at time of void. `void_reason` will be populated if the
+ * void is created with a reason.
+ *
+ * ## Void
+ *
+ * When a set of credits is voided, the customer's balance automatically reflects this change and
+ * adds an entry to the ledger indicating this event.
+ *
+ * ## Amendment
+ *
+ * When credits are added to a customer's balance as a result of a correction, this entry will be
+ * added to the ledger to indicate the adjustment of credits.
+ */
 class CustomerCreditLedgerListParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListResponse.kt
index 9465c031..a38e8399 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditLedgerListResponse.kt
@@ -431,38 +431,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -498,19 +512,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -559,7 +573,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -630,19 +646,23 @@ private constructor(
 
             fun build(): IncrementLedgerEntry =
                 IncrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -672,13 +692,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -704,9 +726,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -721,14 +743,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -758,9 +787,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -802,11 +833,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -831,8 +862,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -846,8 +877,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -877,8 +911,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1203,44 +1239,58 @@ private constructor(
 
         fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("event_id") @ExcludeMissing fun _eventId() = eventId
+        @JsonProperty("event_id") @ExcludeMissing fun _eventId(): JsonField<String> = eventId
 
-        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId() = invoiceId
+        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1279,19 +1329,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var eventId: JsonField<String> = JsonMissing.of()
             private var invoiceId: JsonField<String> = JsonMissing.of()
             private var priceId: JsonField<String> = JsonMissing.of()
@@ -1346,7 +1396,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -1396,15 +1448,21 @@ private constructor(
                 this.startingBalance = startingBalance
             }
 
-            fun eventId(eventId: String) = eventId(JsonField.of(eventId))
+            fun eventId(eventId: String?) = eventId(JsonField.ofNullable(eventId))
+
+            fun eventId(eventId: Optional<String>) = eventId(eventId.orElse(null))
 
             fun eventId(eventId: JsonField<String>) = apply { this.eventId = eventId }
 
-            fun invoiceId(invoiceId: String) = invoiceId(JsonField.of(invoiceId))
+            fun invoiceId(invoiceId: String?) = invoiceId(JsonField.ofNullable(invoiceId))
+
+            fun invoiceId(invoiceId: Optional<String>) = invoiceId(invoiceId.orElse(null))
 
             fun invoiceId(invoiceId: JsonField<String>) = apply { this.invoiceId = invoiceId }
 
-            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
+
+            fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
             fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
 
@@ -1429,19 +1487,23 @@ private constructor(
 
             fun build(): DecrementLedgerEntry =
                 DecrementLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     eventId,
                     invoiceId,
                     priceId,
@@ -1474,13 +1536,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1506,9 +1570,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1523,14 +1587,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -1560,9 +1631,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1604,11 +1677,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1633,8 +1706,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1648,8 +1721,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -1679,8 +1755,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1996,42 +2074,56 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2068,20 +2160,20 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2132,7 +2224,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2175,8 +2269,11 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime) =
-                newBlockExpiryDate(JsonField.of(newBlockExpiryDate))
+            fun newBlockExpiryDate(newBlockExpiryDate: OffsetDateTime?) =
+                newBlockExpiryDate(JsonField.ofNullable(newBlockExpiryDate))
+
+            fun newBlockExpiryDate(newBlockExpiryDate: Optional<OffsetDateTime>) =
+                newBlockExpiryDate(newBlockExpiryDate.orElse(null))
 
             fun newBlockExpiryDate(newBlockExpiryDate: JsonField<OffsetDateTime>) = apply {
                 this.newBlockExpiryDate = newBlockExpiryDate
@@ -2210,20 +2307,26 @@ private constructor(
 
             fun build(): ExpirationChangeLedgerEntry =
                 ExpirationChangeLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2253,13 +2356,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2285,9 +2390,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2302,14 +2407,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -2339,9 +2451,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2383,11 +2497,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2412,8 +2526,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2427,8 +2541,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -2458,8 +2575,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2769,38 +2888,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2836,19 +2969,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2898,7 +3031,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -2969,19 +3104,23 @@ private constructor(
 
             fun build(): CreditBlockExpiryLedgerEntry =
                 CreditBlockExpiryLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3011,13 +3150,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3043,9 +3184,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3060,14 +3201,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3097,9 +3245,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3141,11 +3291,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3170,8 +3320,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3185,8 +3335,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -3216,8 +3369,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3538,42 +3693,60 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3611,21 +3784,21 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3676,7 +3849,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -3730,7 +3905,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -3755,21 +3932,25 @@ private constructor(
 
             fun build(): VoidLedgerEntry =
                 VoidLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3799,13 +3980,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3831,9 +4014,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3848,14 +4031,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -3885,9 +4075,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3929,11 +4121,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3958,8 +4150,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3973,8 +4165,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4004,8 +4199,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4332,46 +4529,64 @@ private constructor(
         fun voidReason(): Optional<String> =
             Optional.ofNullable(voidReason.getNullable("void_reason"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonProperty("new_block_expiry_date")
         @ExcludeMissing
-        fun _newBlockExpiryDate() = newBlockExpiryDate
+        fun _newBlockExpiryDate(): JsonField<OffsetDateTime> = newBlockExpiryDate
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
-        @JsonProperty("void_amount") @ExcludeMissing fun _voidAmount() = voidAmount
+        @JsonProperty("void_amount")
+        @ExcludeMissing
+        fun _voidAmount(): JsonField<Double> = voidAmount
 
-        @JsonProperty("void_reason") @ExcludeMissing fun _voidReason() = voidReason
+        @JsonProperty("void_reason")
+        @ExcludeMissing
+        fun _voidReason(): JsonField<String> = voidReason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4410,22 +4625,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var newBlockExpiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
-            private var voidAmount: JsonField<Double> = JsonMissing.of()
-            private var voidReason: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var newBlockExpiryDate: JsonField<OffsetDateTime>? = null
+            private var startingBalance: JsonField<Double>? = null
+            private var voidAmount: JsonField<Double>? = null
+            private var voidReason: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4477,7 +4692,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -4538,7 +4755,9 @@ private constructor(
 
             fun voidAmount(voidAmount: JsonField<Double>) = apply { this.voidAmount = voidAmount }
 
-            fun voidReason(voidReason: String) = voidReason(JsonField.of(voidReason))
+            fun voidReason(voidReason: String?) = voidReason(JsonField.ofNullable(voidReason))
+
+            fun voidReason(voidReason: Optional<String>) = voidReason(voidReason.orElse(null))
 
             fun voidReason(voidReason: JsonField<String>) = apply { this.voidReason = voidReason }
 
@@ -4563,22 +4782,28 @@ private constructor(
 
             fun build(): VoidInitiatedLedgerEntry =
                 VoidInitiatedLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    newBlockExpiryDate,
-                    startingBalance,
-                    voidAmount,
-                    voidReason,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(newBlockExpiryDate) {
+                        "`newBlockExpiryDate` is required but was not set"
+                    },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(voidAmount) { "`voidAmount` is required but was not set" },
+                    checkNotNull(voidReason) { "`voidReason` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4608,13 +4833,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4640,9 +4867,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4657,14 +4884,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -4694,9 +4928,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4738,11 +4974,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4767,8 +5003,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4782,8 +5018,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -4813,8 +5052,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5124,38 +5365,52 @@ private constructor(
 
         fun startingBalance(): Double = startingBalance.getRequired("starting_balance")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<Double> = amount
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_block") @ExcludeMissing fun _creditBlock() = creditBlock
+        @JsonProperty("credit_block")
+        @ExcludeMissing
+        fun _creditBlock(): JsonField<CreditBlock> = creditBlock
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+        @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<Double> = endingBalance
 
-        @JsonProperty("entry_status") @ExcludeMissing fun _entryStatus() = entryStatus
+        @JsonProperty("entry_status")
+        @ExcludeMissing
+        fun _entryStatus(): JsonField<EntryStatus> = entryStatus
 
-        @JsonProperty("entry_type") @ExcludeMissing fun _entryType() = entryType
+        @JsonProperty("entry_type")
+        @ExcludeMissing
+        fun _entryType(): JsonField<EntryType> = entryType
 
         @JsonProperty("ledger_sequence_number")
         @ExcludeMissing
-        fun _ledgerSequenceNumber() = ledgerSequenceNumber
+        fun _ledgerSequenceNumber(): JsonField<Long> = ledgerSequenceNumber
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<Double> = startingBalance
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5191,19 +5446,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditBlock: JsonField<CreditBlock> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var customer: JsonField<Customer> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<Double> = JsonMissing.of()
-            private var entryStatus: JsonField<EntryStatus> = JsonMissing.of()
-            private var entryType: JsonField<EntryType> = JsonMissing.of()
-            private var ledgerSequenceNumber: JsonField<Long> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var startingBalance: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditBlock: JsonField<CreditBlock>? = null
+            private var currency: JsonField<String>? = null
+            private var customer: JsonField<Customer>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<Double>? = null
+            private var entryStatus: JsonField<EntryStatus>? = null
+            private var entryType: JsonField<EntryType>? = null
+            private var ledgerSequenceNumber: JsonField<Long>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var startingBalance: JsonField<Double>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5252,7 +5507,9 @@ private constructor(
 
             fun customer(customer: JsonField<Customer>) = apply { this.customer = customer }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
@@ -5323,19 +5580,23 @@ private constructor(
 
             fun build(): AmendmentLedgerEntry =
                 AmendmentLedgerEntry(
-                    id,
-                    amount,
-                    createdAt,
-                    creditBlock,
-                    currency,
-                    customer,
-                    description,
-                    endingBalance,
-                    entryStatus,
-                    entryType,
-                    ledgerSequenceNumber,
-                    metadata,
-                    startingBalance,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditBlock) { "`creditBlock` is required but was not set" },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(customer) { "`customer` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(entryStatus) { "`entryStatus` is required but was not set" },
+                    checkNotNull(entryType) { "`entryType` is required but was not set" },
+                    checkNotNull(ledgerSequenceNumber) {
+                        "`ledgerSequenceNumber` is required but was not set"
+                    },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5365,13 +5626,15 @@ private constructor(
             fun perUnitCostBasis(): Optional<String> =
                 Optional.ofNullable(perUnitCostBasis.getNullable("per_unit_cost_basis"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+            @JsonProperty("expiry_date")
+            @ExcludeMissing
+            fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
             @JsonProperty("per_unit_cost_basis")
             @ExcludeMissing
-            fun _perUnitCostBasis() = perUnitCostBasis
+            fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5397,9 +5660,9 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var expiryDate: JsonField<OffsetDateTime>? = null
+                private var perUnitCostBasis: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5414,14 +5677,21 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+                fun expiryDate(expiryDate: OffsetDateTime?) =
+                    expiryDate(JsonField.ofNullable(expiryDate))
+
+                fun expiryDate(expiryDate: Optional<OffsetDateTime>) =
+                    expiryDate(expiryDate.orElse(null))
 
                 fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
                     this.expiryDate = expiryDate
                 }
 
-                fun perUnitCostBasis(perUnitCostBasis: String) =
-                    perUnitCostBasis(JsonField.of(perUnitCostBasis))
+                fun perUnitCostBasis(perUnitCostBasis: String?) =
+                    perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+                fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+                    perUnitCostBasis(perUnitCostBasis.orElse(null))
 
                 fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                     this.perUnitCostBasis = perUnitCostBasis
@@ -5451,9 +5721,11 @@ private constructor(
 
                 fun build(): CreditBlock =
                     CreditBlock(
-                        id,
-                        expiryDate,
-                        perUnitCostBasis,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                        checkNotNull(perUnitCostBasis) {
+                            "`perUnitCostBasis` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5495,11 +5767,11 @@ private constructor(
             fun externalCustomerId(): Optional<String> =
                 Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonProperty("external_customer_id")
             @ExcludeMissing
-            fun _externalCustomerId() = externalCustomerId
+            fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5524,8 +5796,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var externalCustomerId: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var externalCustomerId: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5539,8 +5811,11 @@ private constructor(
 
                 fun id(id: JsonField<String>) = apply { this.id = id }
 
-                fun externalCustomerId(externalCustomerId: String) =
-                    externalCustomerId(JsonField.of(externalCustomerId))
+                fun externalCustomerId(externalCustomerId: String?) =
+                    externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+                fun externalCustomerId(externalCustomerId: Optional<String>) =
+                    externalCustomerId(externalCustomerId.orElse(null))
 
                 fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                     this.externalCustomerId = externalCustomerId
@@ -5570,8 +5845,10 @@ private constructor(
 
                 fun build(): Customer =
                     Customer(
-                        id,
-                        externalCustomerId,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(externalCustomerId) {
+                            "`externalCustomerId` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdParams.kt
index 0d5b699b..dcf9edbb 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdParams.kt
@@ -8,6 +8,15 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Returns a paginated list of unexpired, non-zero credit blocks for a customer.
+ *
+ * If `include_all_blocks` is set to `true`, all credit blocks (including expired and depleted
+ * blocks) will be included in the response.
+ *
+ * Note that `currency` defaults to credits if not specified. To use a real world currency, set
+ * `currency` to an ISO 4217 string.
+ */
 class CustomerCreditListByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdResponse.kt
index e48839cc..0519355a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListByExternalIdResponse.kt
@@ -63,21 +63,27 @@ private constructor(
 
     fun status(): Status = status.getRequired("status")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("balance") @ExcludeMissing fun _balance() = balance
+    @JsonProperty("balance") @ExcludeMissing fun _balance(): JsonField<Double> = balance
 
-    @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+    @JsonProperty("effective_date")
+    @ExcludeMissing
+    fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-    @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+    @JsonProperty("expiry_date")
+    @ExcludeMissing
+    fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
     @JsonProperty("maximum_initial_balance")
     @ExcludeMissing
-    fun _maximumInitialBalance() = maximumInitialBalance
+    fun _maximumInitialBalance(): JsonField<Double> = maximumInitialBalance
 
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -107,13 +113,13 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var balance: JsonField<Double> = JsonMissing.of()
-        private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var maximumInitialBalance: JsonField<Double> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var balance: JsonField<Double>? = null
+        private var effectiveDate: JsonField<OffsetDateTime>? = null
+        private var expiryDate: JsonField<OffsetDateTime>? = null
+        private var maximumInitialBalance: JsonField<Double>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var status: JsonField<Status>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -139,28 +145,43 @@ private constructor(
 
         fun balance(balance: JsonField<Double>) = apply { this.balance = balance }
 
-        fun effectiveDate(effectiveDate: OffsetDateTime) =
-            effectiveDate(JsonField.of(effectiveDate))
+        fun effectiveDate(effectiveDate: OffsetDateTime?) =
+            effectiveDate(JsonField.ofNullable(effectiveDate))
+
+        fun effectiveDate(effectiveDate: Optional<OffsetDateTime>) =
+            effectiveDate(effectiveDate.orElse(null))
 
         fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
             this.effectiveDate = effectiveDate
         }
 
-        fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+        fun expiryDate(expiryDate: OffsetDateTime?) = expiryDate(JsonField.ofNullable(expiryDate))
+
+        fun expiryDate(expiryDate: Optional<OffsetDateTime>) = expiryDate(expiryDate.orElse(null))
 
         fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
             this.expiryDate = expiryDate
         }
 
+        fun maximumInitialBalance(maximumInitialBalance: Double?) =
+            maximumInitialBalance(JsonField.ofNullable(maximumInitialBalance))
+
         fun maximumInitialBalance(maximumInitialBalance: Double) =
-            maximumInitialBalance(JsonField.of(maximumInitialBalance))
+            maximumInitialBalance(maximumInitialBalance as Double?)
+
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun maximumInitialBalance(maximumInitialBalance: Optional<Double>) =
+            maximumInitialBalance(maximumInitialBalance.orElse(null) as Double?)
 
         fun maximumInitialBalance(maximumInitialBalance: JsonField<Double>) = apply {
             this.maximumInitialBalance = maximumInitialBalance
         }
 
-        fun perUnitCostBasis(perUnitCostBasis: String) =
-            perUnitCostBasis(JsonField.of(perUnitCostBasis))
+        fun perUnitCostBasis(perUnitCostBasis: String?) =
+            perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+        fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+            perUnitCostBasis(perUnitCostBasis.orElse(null))
 
         fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
             this.perUnitCostBasis = perUnitCostBasis
@@ -191,13 +212,15 @@ private constructor(
 
         fun build(): CustomerCreditListByExternalIdResponse =
             CustomerCreditListByExternalIdResponse(
-                id,
-                balance,
-                effectiveDate,
-                expiryDate,
-                maximumInitialBalance,
-                perUnitCostBasis,
-                status,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(balance) { "`balance` is required but was not set" },
+                checkNotNull(effectiveDate) { "`effectiveDate` is required but was not set" },
+                checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                checkNotNull(maximumInitialBalance) {
+                    "`maximumInitialBalance` is required but was not set"
+                },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListParams.kt
index 7834e45b..a0d5a550 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListParams.kt
@@ -8,6 +8,15 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Returns a paginated list of unexpired, non-zero credit blocks for a customer.
+ *
+ * If `include_all_blocks` is set to `true`, all credit blocks (including expired and depleted
+ * blocks) will be included in the response.
+ *
+ * Note that `currency` defaults to credits if not specified. To use a real world currency, set
+ * `currency` to an ISO 4217 string.
+ */
 class CustomerCreditListParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListResponse.kt
index c568724b..7b4ab765 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditListResponse.kt
@@ -63,21 +63,27 @@ private constructor(
 
     fun status(): Status = status.getRequired("status")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("balance") @ExcludeMissing fun _balance() = balance
+    @JsonProperty("balance") @ExcludeMissing fun _balance(): JsonField<Double> = balance
 
-    @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+    @JsonProperty("effective_date")
+    @ExcludeMissing
+    fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-    @JsonProperty("expiry_date") @ExcludeMissing fun _expiryDate() = expiryDate
+    @JsonProperty("expiry_date")
+    @ExcludeMissing
+    fun _expiryDate(): JsonField<OffsetDateTime> = expiryDate
 
     @JsonProperty("maximum_initial_balance")
     @ExcludeMissing
-    fun _maximumInitialBalance() = maximumInitialBalance
+    fun _maximumInitialBalance(): JsonField<Double> = maximumInitialBalance
 
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -107,13 +113,13 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var balance: JsonField<Double> = JsonMissing.of()
-        private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var expiryDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var maximumInitialBalance: JsonField<Double> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var balance: JsonField<Double>? = null
+        private var effectiveDate: JsonField<OffsetDateTime>? = null
+        private var expiryDate: JsonField<OffsetDateTime>? = null
+        private var maximumInitialBalance: JsonField<Double>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var status: JsonField<Status>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -136,28 +142,43 @@ private constructor(
 
         fun balance(balance: JsonField<Double>) = apply { this.balance = balance }
 
-        fun effectiveDate(effectiveDate: OffsetDateTime) =
-            effectiveDate(JsonField.of(effectiveDate))
+        fun effectiveDate(effectiveDate: OffsetDateTime?) =
+            effectiveDate(JsonField.ofNullable(effectiveDate))
+
+        fun effectiveDate(effectiveDate: Optional<OffsetDateTime>) =
+            effectiveDate(effectiveDate.orElse(null))
 
         fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
             this.effectiveDate = effectiveDate
         }
 
-        fun expiryDate(expiryDate: OffsetDateTime) = expiryDate(JsonField.of(expiryDate))
+        fun expiryDate(expiryDate: OffsetDateTime?) = expiryDate(JsonField.ofNullable(expiryDate))
+
+        fun expiryDate(expiryDate: Optional<OffsetDateTime>) = expiryDate(expiryDate.orElse(null))
 
         fun expiryDate(expiryDate: JsonField<OffsetDateTime>) = apply {
             this.expiryDate = expiryDate
         }
 
+        fun maximumInitialBalance(maximumInitialBalance: Double?) =
+            maximumInitialBalance(JsonField.ofNullable(maximumInitialBalance))
+
         fun maximumInitialBalance(maximumInitialBalance: Double) =
-            maximumInitialBalance(JsonField.of(maximumInitialBalance))
+            maximumInitialBalance(maximumInitialBalance as Double?)
+
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun maximumInitialBalance(maximumInitialBalance: Optional<Double>) =
+            maximumInitialBalance(maximumInitialBalance.orElse(null) as Double?)
 
         fun maximumInitialBalance(maximumInitialBalance: JsonField<Double>) = apply {
             this.maximumInitialBalance = maximumInitialBalance
         }
 
-        fun perUnitCostBasis(perUnitCostBasis: String) =
-            perUnitCostBasis(JsonField.of(perUnitCostBasis))
+        fun perUnitCostBasis(perUnitCostBasis: String?) =
+            perUnitCostBasis(JsonField.ofNullable(perUnitCostBasis))
+
+        fun perUnitCostBasis(perUnitCostBasis: Optional<String>) =
+            perUnitCostBasis(perUnitCostBasis.orElse(null))
 
         fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
             this.perUnitCostBasis = perUnitCostBasis
@@ -188,13 +209,15 @@ private constructor(
 
         fun build(): CustomerCreditListResponse =
             CustomerCreditListResponse(
-                id,
-                balance,
-                effectiveDate,
-                expiryDate,
-                maximumInitialBalance,
-                perUnitCostBasis,
-                status,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(balance) { "`balance` is required but was not set" },
+                checkNotNull(effectiveDate) { "`effectiveDate` is required but was not set" },
+                checkNotNull(expiryDate) { "`expiryDate` is required but was not set" },
+                checkNotNull(maximumInitialBalance) {
+                    "`maximumInitialBalance` is required but was not set"
+                },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdParams.kt
index 03ff4dff..c6eeec34 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,14 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to create a new top-up for a specified customer's balance. While this
+ * top-up is active, the customer's balance will added in increments of the specified amount
+ * whenever the balance reaches the specified threshold.
+ *
+ * If a top-up already exists for this customer in the same currency, the existing top-up will be
+ * replaced.
+ */
 class CustomerCreditTopUpCreateByExternalIdParams
 constructor(
     private val externalCustomerId: String,
@@ -59,12 +68,42 @@ constructor(
     /** The unit of expires_after. */
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> = body.expiresAfterUnit()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The amount to increment when the threshold is reached. */
+    fun _amount(): JsonField<String> = body._amount()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
+     * it must match the customer's invoicing currency.
+     */
+    fun _currency(): JsonField<String> = body._currency()
+
+    /** Settings for invoices generated by triggered top-ups. */
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = body._invoiceSettings()
+
+    /** How much, in the customer's currency, to charge for each unit. */
+    fun _perUnitCostBasis(): JsonField<String> = body._perUnitCostBasis()
+
+    /**
+     * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
+     * the top-up will be triggered.
+     */
+    fun _threshold(): JsonField<String> = body._threshold()
+
+    /**
+     * The number of days or months after which the top-up expires. If unspecified, it does not
+     * expire.
+     */
+    fun _expiresAfter(): JsonField<Long> = body._expiresAfter()
+
+    /** The unit of expires_after. */
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = body._expiresAfterUnit()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerCreditTopUpCreateByExternalIdBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -82,53 +121,120 @@ constructor(
     class CustomerCreditTopUpCreateByExternalIdBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("amount") private val amount: String,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("invoice_settings") private val invoiceSettings: InvoiceSettings,
-        @JsonProperty("per_unit_cost_basis") private val perUnitCostBasis: String,
-        @JsonProperty("threshold") private val threshold: String,
-        @JsonProperty("expires_after") private val expiresAfter: Long?,
-        @JsonProperty("expires_after_unit") private val expiresAfterUnit: ExpiresAfterUnit?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        private val invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of(),
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        private val perUnitCostBasis: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("threshold")
+        @ExcludeMissing
+        private val threshold: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("expires_after")
+        @ExcludeMissing
+        private val expiresAfter: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("expires_after_unit")
+        @ExcludeMissing
+        private val expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The amount to increment when the threshold is reached. */
-        @JsonProperty("amount") fun amount(): String = amount
+        fun amount(): String = amount.getRequired("amount")
+
+        /**
+         * The currency or custom pricing unit to use for this top-up. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** Settings for invoices generated by triggered top-ups. */
+        fun invoiceSettings(): InvoiceSettings = invoiceSettings.getRequired("invoice_settings")
+
+        /** How much, in the customer's currency, to charge for each unit. */
+        fun perUnitCostBasis(): String = perUnitCostBasis.getRequired("per_unit_cost_basis")
+
+        /**
+         * The threshold at which to trigger the top-up. If the balance is at or below this
+         * threshold, the top-up will be triggered.
+         */
+        fun threshold(): String = threshold.getRequired("threshold")
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(): Optional<Long> =
+            Optional.ofNullable(expiresAfter.getNullable("expires_after"))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
+            Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
+
+        /** The amount to increment when the threshold is reached. */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /**
          * The currency or custom pricing unit to use for this top-up. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** Settings for invoices generated by triggered top-ups. */
-        @JsonProperty("invoice_settings") fun invoiceSettings(): InvoiceSettings = invoiceSettings
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
         /** How much, in the customer's currency, to charge for each unit. */
-        @JsonProperty("per_unit_cost_basis") fun perUnitCostBasis(): String = perUnitCostBasis
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
         /**
          * The threshold at which to trigger the top-up. If the balance is at or below this
          * threshold, the top-up will be triggered.
          */
-        @JsonProperty("threshold") fun threshold(): String = threshold
+        @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
         @JsonProperty("expires_after")
-        fun expiresAfter(): Optional<Long> = Optional.ofNullable(expiresAfter)
+        @ExcludeMissing
+        fun _expiresAfter(): JsonField<Long> = expiresAfter
 
         /** The unit of expires_after. */
         @JsonProperty("expires_after_unit")
-        fun expiresAfterUnit(): Optional<ExpiresAfterUnit> = Optional.ofNullable(expiresAfterUnit)
+        @ExcludeMissing
+        fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerCreditTopUpCreateByExternalIdBody = apply {
+            if (!validated) {
+                amount()
+                currency()
+                invoiceSettings().validate()
+                perUnitCostBasis()
+                threshold()
+                expiresAfter()
+                expiresAfterUnit()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -138,13 +244,13 @@ constructor(
 
         class Builder {
 
-            private var amount: String? = null
-            private var currency: String? = null
-            private var invoiceSettings: InvoiceSettings? = null
-            private var perUnitCostBasis: String? = null
-            private var threshold: String? = null
-            private var expiresAfter: Long? = null
-            private var expiresAfterUnit: ExpiresAfterUnit? = null
+            private var amount: JsonField<String>? = null
+            private var currency: JsonField<String>? = null
+            private var invoiceSettings: JsonField<InvoiceSettings>? = null
+            private var perUnitCostBasis: JsonField<String>? = null
+            private var threshold: JsonField<String>? = null
+            private var expiresAfter: JsonField<Long> = JsonMissing.of()
+            private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -163,21 +269,38 @@ constructor(
             }
 
             /** The amount to increment when the threshold is reached. */
-            fun amount(amount: String) = apply { this.amount = amount }
+            fun amount(amount: String) = amount(JsonField.of(amount))
+
+            /** The amount to increment when the threshold is reached. */
+            fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
             /**
              * The currency or custom pricing unit to use for this top-up. If this is a real-world
              * currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /**
+             * The currency or custom pricing unit to use for this top-up. If this is a real-world
+             * currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /** Settings for invoices generated by triggered top-ups. */
-            fun invoiceSettings(invoiceSettings: InvoiceSettings) = apply {
+            fun invoiceSettings(invoiceSettings: InvoiceSettings) =
+                invoiceSettings(JsonField.of(invoiceSettings))
+
+            /** Settings for invoices generated by triggered top-ups. */
+            fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
                 this.invoiceSettings = invoiceSettings
             }
 
             /** How much, in the customer's currency, to charge for each unit. */
-            fun perUnitCostBasis(perUnitCostBasis: String) = apply {
+            fun perUnitCostBasis(perUnitCostBasis: String) =
+                perUnitCostBasis(JsonField.of(perUnitCostBasis))
+
+            /** How much, in the customer's currency, to charge for each unit. */
+            fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                 this.perUnitCostBasis = perUnitCostBasis
             }
 
@@ -185,13 +308,19 @@ constructor(
              * The threshold at which to trigger the top-up. If the balance is at or below this
              * threshold, the top-up will be triggered.
              */
-            fun threshold(threshold: String) = apply { this.threshold = threshold }
+            fun threshold(threshold: String) = threshold(JsonField.of(threshold))
+
+            /**
+             * The threshold at which to trigger the top-up. If the balance is at or below this
+             * threshold, the top-up will be triggered.
+             */
+            fun threshold(threshold: JsonField<String>) = apply { this.threshold = threshold }
 
             /**
              * The number of days or months after which the top-up expires. If unspecified, it does
              * not expire.
              */
-            fun expiresAfter(expiresAfter: Long?) = apply { this.expiresAfter = expiresAfter }
+            fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
 
             /**
              * The number of days or months after which the top-up expires. If unspecified, it does
@@ -207,15 +336,27 @@ constructor(
             fun expiresAfter(expiresAfter: Optional<Long>) =
                 expiresAfter(expiresAfter.orElse(null) as Long?)
 
-            /** The unit of expires_after. */
-            fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) = apply {
-                this.expiresAfterUnit = expiresAfterUnit
+            /**
+             * The number of days or months after which the top-up expires. If unspecified, it does
+             * not expire.
+             */
+            fun expiresAfter(expiresAfter: JsonField<Long>) = apply {
+                this.expiresAfter = expiresAfter
             }
 
+            /** The unit of expires_after. */
+            fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+                expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
             /** The unit of expires_after. */
             fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
                 expiresAfterUnit(expiresAfterUnit.orElse(null))
 
+            /** The unit of expires_after. */
+            fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
+                this.expiresAfterUnit = expiresAfterUnit
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -305,28 +446,53 @@ constructor(
         /** The amount to increment when the threshold is reached. */
         fun amount(amount: String) = apply { body.amount(amount) }
 
+        /** The amount to increment when the threshold is reached. */
+        fun amount(amount: JsonField<String>) = apply { body.amount(amount) }
+
         /**
          * The currency or custom pricing unit to use for this top-up. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /**
+         * The currency or custom pricing unit to use for this top-up. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** Settings for invoices generated by triggered top-ups. */
         fun invoiceSettings(invoiceSettings: InvoiceSettings) = apply {
             body.invoiceSettings(invoiceSettings)
         }
 
+        /** Settings for invoices generated by triggered top-ups. */
+        fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
+            body.invoiceSettings(invoiceSettings)
+        }
+
         /** How much, in the customer's currency, to charge for each unit. */
         fun perUnitCostBasis(perUnitCostBasis: String) = apply {
             body.perUnitCostBasis(perUnitCostBasis)
         }
 
+        /** How much, in the customer's currency, to charge for each unit. */
+        fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
+            body.perUnitCostBasis(perUnitCostBasis)
+        }
+
         /**
          * The threshold at which to trigger the top-up. If the balance is at or below this
          * threshold, the top-up will be triggered.
          */
         fun threshold(threshold: String) = apply { body.threshold(threshold) }
 
+        /**
+         * The threshold at which to trigger the top-up. If the balance is at or below this
+         * threshold, the top-up will be triggered.
+         */
+        fun threshold(threshold: JsonField<String>) = apply { body.threshold(threshold) }
+
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
@@ -347,6 +513,12 @@ constructor(
         fun expiresAfter(expiresAfter: Optional<Long>) =
             expiresAfter(expiresAfter.orElse(null) as Long?)
 
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: JsonField<Long>) = apply { body.expiresAfter(expiresAfter) }
+
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) = apply {
             body.expiresAfterUnit(expiresAfterUnit)
@@ -356,6 +528,30 @@ constructor(
         fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
             expiresAfterUnit(expiresAfterUnit.orElse(null))
 
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
+            body.expiresAfterUnit(expiresAfterUnit)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -454,25 +650,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerCreditTopUpCreateByExternalIdParams =
             CustomerCreditTopUpCreateByExternalIdParams(
                 checkNotNull(externalCustomerId) {
@@ -489,10 +666,18 @@ constructor(
     class InvoiceSettings
     @JsonCreator
     private constructor(
-        @JsonProperty("auto_collection") private val autoCollection: Boolean,
-        @JsonProperty("net_terms") private val netTerms: Long,
-        @JsonProperty("memo") private val memo: String?,
-        @JsonProperty("require_successful_payment") private val requireSuccessfulPayment: Boolean?,
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("memo")
+        @ExcludeMissing
+        private val memo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("require_successful_payment")
+        @ExcludeMissing
+        private val requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -501,29 +686,65 @@ constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") fun autoCollection(): Boolean = autoCollection
+        fun autoCollection(): Boolean = autoCollection.getRequired("auto_collection")
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") fun netTerms(): Long = netTerms
+        fun netTerms(): Long = netTerms.getRequired("net_terms")
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+        fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
          * invoice is paid before they can be drawn down from.
          */
-        @JsonProperty("require_successful_payment")
         fun requireSuccessfulPayment(): Optional<Boolean> =
-            Optional.ofNullable(requireSuccessfulPayment)
+            Optional.ofNullable(requireSuccessfulPayment.getNullable("require_successful_payment"))
+
+        /**
+         * Whether the credits purchase invoice should auto collect with the customer's saved
+         * payment method.
+         */
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
+
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0.
+         */
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
+
+        /** An optional memo to display on the invoice. */
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
+
+        /**
+         * If true, new credit blocks created by this top-up will require that the corresponding
+         * invoice is paid before they can be drawn down from.
+         */
+        @JsonProperty("require_successful_payment")
+        @ExcludeMissing
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceSettings = apply {
+            if (!validated) {
+                autoCollection()
+                netTerms()
+                memo()
+                requireSuccessfulPayment()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -533,10 +754,10 @@ constructor(
 
         class Builder {
 
-            private var autoCollection: Boolean? = null
-            private var netTerms: Long? = null
-            private var memo: String? = null
-            private var requireSuccessfulPayment: Boolean? = null
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
+            private var memo: JsonField<String> = JsonMissing.of()
+            private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -552,7 +773,14 @@ constructor(
              * Whether the credits purchase invoice should auto collect with the customer's saved
              * payment method.
              */
-            fun autoCollection(autoCollection: Boolean) = apply {
+            fun autoCollection(autoCollection: Boolean) =
+                autoCollection(JsonField.of(autoCollection))
+
+            /**
+             * Whether the credits purchase invoice should auto collect with the customer's saved
+             * payment method.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
                 this.autoCollection = autoCollection
             }
 
@@ -560,36 +788,37 @@ constructor(
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0.
              */
-            fun netTerms(netTerms: Long) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String?) = apply { this.memo = memo }
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
-            /**
-             * If true, new credit blocks created by this top-up will require that the corresponding
-             * invoice is paid before they can be drawn down from.
-             */
-            fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean?) = apply {
-                this.requireSuccessfulPayment = requireSuccessfulPayment
-            }
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: JsonField<String>) = apply { this.memo = memo }
 
             /**
              * If true, new credit blocks created by this top-up will require that the corresponding
              * invoice is paid before they can be drawn down from.
              */
             fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean) =
-                requireSuccessfulPayment(requireSuccessfulPayment as Boolean?)
+                requireSuccessfulPayment(JsonField.of(requireSuccessfulPayment))
 
             /**
              * If true, new credit blocks created by this top-up will require that the corresponding
              * invoice is paid before they can be drawn down from.
              */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun requireSuccessfulPayment(requireSuccessfulPayment: Optional<Boolean>) =
-                requireSuccessfulPayment(requireSuccessfulPayment.orElse(null) as Boolean?)
+            fun requireSuccessfulPayment(requireSuccessfulPayment: JsonField<Boolean>) = apply {
+                this.requireSuccessfulPayment = requireSuccessfulPayment
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdResponse.kt
index c18400a8..fcd28688 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateByExternalIdResponse.kt
@@ -81,37 +81,45 @@ private constructor(
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
         Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The amount to increment when the threshold is reached. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /**
      * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
      * it must match the customer's invoicing currency.
      */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /** Settings for invoices generated by triggered top-ups. */
-    @JsonProperty("invoice_settings") @ExcludeMissing fun _invoiceSettings() = invoiceSettings
+    @JsonProperty("invoice_settings")
+    @ExcludeMissing
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
     /** How much, in the customer's currency, to charge for each unit. */
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
     /**
      * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
      * the top-up will be triggered.
      */
-    @JsonProperty("threshold") @ExcludeMissing fun _threshold() = threshold
+    @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
     /**
      * The number of days or months after which the top-up expires. If unspecified, it does not
      * expire.
      */
-    @JsonProperty("expires_after") @ExcludeMissing fun _expiresAfter() = expiresAfter
+    @JsonProperty("expires_after")
+    @ExcludeMissing
+    fun _expiresAfter(): JsonField<Long> = expiresAfter
 
     /** The unit of expires_after. */
-    @JsonProperty("expires_after_unit") @ExcludeMissing fun _expiresAfterUnit() = expiresAfterUnit
+    @JsonProperty("expires_after_unit")
+    @ExcludeMissing
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -142,12 +150,12 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var threshold: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amount: JsonField<String>? = null
+        private var currency: JsonField<String>? = null
+        private var invoiceSettings: JsonField<InvoiceSettings>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var threshold: JsonField<String>? = null
         private var expiresAfter: JsonField<Long> = JsonMissing.of()
         private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -225,7 +233,21 @@ private constructor(
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
-        fun expiresAfter(expiresAfter: Long) = expiresAfter(JsonField.of(expiresAfter))
+        fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: Long) = expiresAfter(expiresAfter as Long?)
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun expiresAfter(expiresAfter: Optional<Long>) =
+            expiresAfter(expiresAfter.orElse(null) as Long?)
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
@@ -234,8 +256,12 @@ private constructor(
         fun expiresAfter(expiresAfter: JsonField<Long>) = apply { this.expiresAfter = expiresAfter }
 
         /** The unit of expires_after. */
-        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit) =
-            expiresAfterUnit(JsonField.of(expiresAfterUnit))
+        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+            expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
+            expiresAfterUnit(expiresAfterUnit.orElse(null))
 
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
@@ -263,12 +289,12 @@ private constructor(
 
         fun build(): CustomerCreditTopUpCreateByExternalIdResponse =
             CustomerCreditTopUpCreateByExternalIdResponse(
-                id,
-                amount,
-                currency,
-                invoiceSettings,
-                perUnitCostBasis,
-                threshold,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(invoiceSettings) { "`invoiceSettings` is required but was not set" },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(threshold) { "`threshold` is required but was not set" },
                 expiresAfter,
                 expiresAfterUnit,
                 additionalProperties.toImmutable(),
@@ -322,16 +348,18 @@ private constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
@@ -339,7 +367,7 @@ private constructor(
          */
         @JsonProperty("require_successful_payment")
         @ExcludeMissing
-        fun _requireSuccessfulPayment() = requireSuccessfulPayment
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -366,8 +394,8 @@ private constructor(
 
         class Builder {
 
-            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
             private var memo: JsonField<String> = JsonMissing.of()
             private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -409,7 +437,10 @@ private constructor(
             fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -450,8 +481,8 @@ private constructor(
 
             fun build(): InvoiceSettings =
                 InvoiceSettings(
-                    autoCollection,
-                    netTerms,
+                    checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                    checkNotNull(netTerms) { "`netTerms` is required but was not set" },
                     memo,
                     requireSuccessfulPayment,
                     additionalProperties.toImmutable(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateParams.kt
index 52cea74b..af24104e 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,14 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to create a new top-up for a specified customer's balance. While this
+ * top-up is active, the customer's balance will added in increments of the specified amount
+ * whenever the balance reaches the specified threshold.
+ *
+ * If a top-up already exists for this customer in the same currency, the existing top-up will be
+ * replaced.
+ */
 class CustomerCreditTopUpCreateParams
 constructor(
     private val customerId: String,
@@ -59,12 +68,42 @@ constructor(
     /** The unit of expires_after. */
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> = body.expiresAfterUnit()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The amount to increment when the threshold is reached. */
+    fun _amount(): JsonField<String> = body._amount()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
+     * it must match the customer's invoicing currency.
+     */
+    fun _currency(): JsonField<String> = body._currency()
+
+    /** Settings for invoices generated by triggered top-ups. */
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = body._invoiceSettings()
+
+    /** How much, in the customer's currency, to charge for each unit. */
+    fun _perUnitCostBasis(): JsonField<String> = body._perUnitCostBasis()
+
+    /**
+     * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
+     * the top-up will be triggered.
+     */
+    fun _threshold(): JsonField<String> = body._threshold()
+
+    /**
+     * The number of days or months after which the top-up expires. If unspecified, it does not
+     * expire.
+     */
+    fun _expiresAfter(): JsonField<Long> = body._expiresAfter()
+
+    /** The unit of expires_after. */
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = body._expiresAfterUnit()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerCreditTopUpCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -82,53 +121,120 @@ constructor(
     class CustomerCreditTopUpCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("amount") private val amount: String,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("invoice_settings") private val invoiceSettings: InvoiceSettings,
-        @JsonProperty("per_unit_cost_basis") private val perUnitCostBasis: String,
-        @JsonProperty("threshold") private val threshold: String,
-        @JsonProperty("expires_after") private val expiresAfter: Long?,
-        @JsonProperty("expires_after_unit") private val expiresAfterUnit: ExpiresAfterUnit?,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        private val invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of(),
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        private val perUnitCostBasis: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("threshold")
+        @ExcludeMissing
+        private val threshold: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("expires_after")
+        @ExcludeMissing
+        private val expiresAfter: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("expires_after_unit")
+        @ExcludeMissing
+        private val expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The amount to increment when the threshold is reached. */
-        @JsonProperty("amount") fun amount(): String = amount
+        fun amount(): String = amount.getRequired("amount")
+
+        /**
+         * The currency or custom pricing unit to use for this top-up. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** Settings for invoices generated by triggered top-ups. */
+        fun invoiceSettings(): InvoiceSettings = invoiceSettings.getRequired("invoice_settings")
+
+        /** How much, in the customer's currency, to charge for each unit. */
+        fun perUnitCostBasis(): String = perUnitCostBasis.getRequired("per_unit_cost_basis")
+
+        /**
+         * The threshold at which to trigger the top-up. If the balance is at or below this
+         * threshold, the top-up will be triggered.
+         */
+        fun threshold(): String = threshold.getRequired("threshold")
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(): Optional<Long> =
+            Optional.ofNullable(expiresAfter.getNullable("expires_after"))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
+            Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
+
+        /** The amount to increment when the threshold is reached. */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /**
          * The currency or custom pricing unit to use for this top-up. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** Settings for invoices generated by triggered top-ups. */
-        @JsonProperty("invoice_settings") fun invoiceSettings(): InvoiceSettings = invoiceSettings
+        @JsonProperty("invoice_settings")
+        @ExcludeMissing
+        fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
         /** How much, in the customer's currency, to charge for each unit. */
-        @JsonProperty("per_unit_cost_basis") fun perUnitCostBasis(): String = perUnitCostBasis
+        @JsonProperty("per_unit_cost_basis")
+        @ExcludeMissing
+        fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
         /**
          * The threshold at which to trigger the top-up. If the balance is at or below this
          * threshold, the top-up will be triggered.
          */
-        @JsonProperty("threshold") fun threshold(): String = threshold
+        @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
         @JsonProperty("expires_after")
-        fun expiresAfter(): Optional<Long> = Optional.ofNullable(expiresAfter)
+        @ExcludeMissing
+        fun _expiresAfter(): JsonField<Long> = expiresAfter
 
         /** The unit of expires_after. */
         @JsonProperty("expires_after_unit")
-        fun expiresAfterUnit(): Optional<ExpiresAfterUnit> = Optional.ofNullable(expiresAfterUnit)
+        @ExcludeMissing
+        fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerCreditTopUpCreateBody = apply {
+            if (!validated) {
+                amount()
+                currency()
+                invoiceSettings().validate()
+                perUnitCostBasis()
+                threshold()
+                expiresAfter()
+                expiresAfterUnit()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -138,13 +244,13 @@ constructor(
 
         class Builder {
 
-            private var amount: String? = null
-            private var currency: String? = null
-            private var invoiceSettings: InvoiceSettings? = null
-            private var perUnitCostBasis: String? = null
-            private var threshold: String? = null
-            private var expiresAfter: Long? = null
-            private var expiresAfterUnit: ExpiresAfterUnit? = null
+            private var amount: JsonField<String>? = null
+            private var currency: JsonField<String>? = null
+            private var invoiceSettings: JsonField<InvoiceSettings>? = null
+            private var perUnitCostBasis: JsonField<String>? = null
+            private var threshold: JsonField<String>? = null
+            private var expiresAfter: JsonField<Long> = JsonMissing.of()
+            private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -162,21 +268,38 @@ constructor(
                 }
 
             /** The amount to increment when the threshold is reached. */
-            fun amount(amount: String) = apply { this.amount = amount }
+            fun amount(amount: String) = amount(JsonField.of(amount))
+
+            /** The amount to increment when the threshold is reached. */
+            fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
             /**
              * The currency or custom pricing unit to use for this top-up. If this is a real-world
              * currency, it must match the customer's invoicing currency.
              */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /**
+             * The currency or custom pricing unit to use for this top-up. If this is a real-world
+             * currency, it must match the customer's invoicing currency.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /** Settings for invoices generated by triggered top-ups. */
-            fun invoiceSettings(invoiceSettings: InvoiceSettings) = apply {
+            fun invoiceSettings(invoiceSettings: InvoiceSettings) =
+                invoiceSettings(JsonField.of(invoiceSettings))
+
+            /** Settings for invoices generated by triggered top-ups. */
+            fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
                 this.invoiceSettings = invoiceSettings
             }
 
             /** How much, in the customer's currency, to charge for each unit. */
-            fun perUnitCostBasis(perUnitCostBasis: String) = apply {
+            fun perUnitCostBasis(perUnitCostBasis: String) =
+                perUnitCostBasis(JsonField.of(perUnitCostBasis))
+
+            /** How much, in the customer's currency, to charge for each unit. */
+            fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
                 this.perUnitCostBasis = perUnitCostBasis
             }
 
@@ -184,13 +307,19 @@ constructor(
              * The threshold at which to trigger the top-up. If the balance is at or below this
              * threshold, the top-up will be triggered.
              */
-            fun threshold(threshold: String) = apply { this.threshold = threshold }
+            fun threshold(threshold: String) = threshold(JsonField.of(threshold))
+
+            /**
+             * The threshold at which to trigger the top-up. If the balance is at or below this
+             * threshold, the top-up will be triggered.
+             */
+            fun threshold(threshold: JsonField<String>) = apply { this.threshold = threshold }
 
             /**
              * The number of days or months after which the top-up expires. If unspecified, it does
              * not expire.
              */
-            fun expiresAfter(expiresAfter: Long?) = apply { this.expiresAfter = expiresAfter }
+            fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
 
             /**
              * The number of days or months after which the top-up expires. If unspecified, it does
@@ -206,15 +335,27 @@ constructor(
             fun expiresAfter(expiresAfter: Optional<Long>) =
                 expiresAfter(expiresAfter.orElse(null) as Long?)
 
-            /** The unit of expires_after. */
-            fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) = apply {
-                this.expiresAfterUnit = expiresAfterUnit
+            /**
+             * The number of days or months after which the top-up expires. If unspecified, it does
+             * not expire.
+             */
+            fun expiresAfter(expiresAfter: JsonField<Long>) = apply {
+                this.expiresAfter = expiresAfter
             }
 
+            /** The unit of expires_after. */
+            fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+                expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
             /** The unit of expires_after. */
             fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
                 expiresAfterUnit(expiresAfterUnit.orElse(null))
 
+            /** The unit of expires_after. */
+            fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
+                this.expiresAfterUnit = expiresAfterUnit
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -300,28 +441,53 @@ constructor(
         /** The amount to increment when the threshold is reached. */
         fun amount(amount: String) = apply { body.amount(amount) }
 
+        /** The amount to increment when the threshold is reached. */
+        fun amount(amount: JsonField<String>) = apply { body.amount(amount) }
+
         /**
          * The currency or custom pricing unit to use for this top-up. If this is a real-world
          * currency, it must match the customer's invoicing currency.
          */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /**
+         * The currency or custom pricing unit to use for this top-up. If this is a real-world
+         * currency, it must match the customer's invoicing currency.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** Settings for invoices generated by triggered top-ups. */
         fun invoiceSettings(invoiceSettings: InvoiceSettings) = apply {
             body.invoiceSettings(invoiceSettings)
         }
 
+        /** Settings for invoices generated by triggered top-ups. */
+        fun invoiceSettings(invoiceSettings: JsonField<InvoiceSettings>) = apply {
+            body.invoiceSettings(invoiceSettings)
+        }
+
         /** How much, in the customer's currency, to charge for each unit. */
         fun perUnitCostBasis(perUnitCostBasis: String) = apply {
             body.perUnitCostBasis(perUnitCostBasis)
         }
 
+        /** How much, in the customer's currency, to charge for each unit. */
+        fun perUnitCostBasis(perUnitCostBasis: JsonField<String>) = apply {
+            body.perUnitCostBasis(perUnitCostBasis)
+        }
+
         /**
          * The threshold at which to trigger the top-up. If the balance is at or below this
          * threshold, the top-up will be triggered.
          */
         fun threshold(threshold: String) = apply { body.threshold(threshold) }
 
+        /**
+         * The threshold at which to trigger the top-up. If the balance is at or below this
+         * threshold, the top-up will be triggered.
+         */
+        fun threshold(threshold: JsonField<String>) = apply { body.threshold(threshold) }
+
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
@@ -342,6 +508,12 @@ constructor(
         fun expiresAfter(expiresAfter: Optional<Long>) =
             expiresAfter(expiresAfter.orElse(null) as Long?)
 
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: JsonField<Long>) = apply { body.expiresAfter(expiresAfter) }
+
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) = apply {
             body.expiresAfterUnit(expiresAfterUnit)
@@ -351,6 +523,30 @@ constructor(
         fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
             expiresAfterUnit(expiresAfterUnit.orElse(null))
 
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
+            body.expiresAfterUnit(expiresAfterUnit)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -449,25 +645,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerCreditTopUpCreateParams =
             CustomerCreditTopUpCreateParams(
                 checkNotNull(customerId) { "`customerId` is required but was not set" },
@@ -482,10 +659,18 @@ constructor(
     class InvoiceSettings
     @JsonCreator
     private constructor(
-        @JsonProperty("auto_collection") private val autoCollection: Boolean,
-        @JsonProperty("net_terms") private val netTerms: Long,
-        @JsonProperty("memo") private val memo: String?,
-        @JsonProperty("require_successful_payment") private val requireSuccessfulPayment: Boolean?,
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("memo")
+        @ExcludeMissing
+        private val memo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("require_successful_payment")
+        @ExcludeMissing
+        private val requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -494,29 +679,65 @@ constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") fun autoCollection(): Boolean = autoCollection
+        fun autoCollection(): Boolean = autoCollection.getRequired("auto_collection")
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") fun netTerms(): Long = netTerms
+        fun netTerms(): Long = netTerms.getRequired("net_terms")
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+        fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
          * invoice is paid before they can be drawn down from.
          */
-        @JsonProperty("require_successful_payment")
         fun requireSuccessfulPayment(): Optional<Boolean> =
-            Optional.ofNullable(requireSuccessfulPayment)
+            Optional.ofNullable(requireSuccessfulPayment.getNullable("require_successful_payment"))
+
+        /**
+         * Whether the credits purchase invoice should auto collect with the customer's saved
+         * payment method.
+         */
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
+
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0.
+         */
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
+
+        /** An optional memo to display on the invoice. */
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
+
+        /**
+         * If true, new credit blocks created by this top-up will require that the corresponding
+         * invoice is paid before they can be drawn down from.
+         */
+        @JsonProperty("require_successful_payment")
+        @ExcludeMissing
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceSettings = apply {
+            if (!validated) {
+                autoCollection()
+                netTerms()
+                memo()
+                requireSuccessfulPayment()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -526,10 +747,10 @@ constructor(
 
         class Builder {
 
-            private var autoCollection: Boolean? = null
-            private var netTerms: Long? = null
-            private var memo: String? = null
-            private var requireSuccessfulPayment: Boolean? = null
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
+            private var memo: JsonField<String> = JsonMissing.of()
+            private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -545,7 +766,14 @@ constructor(
              * Whether the credits purchase invoice should auto collect with the customer's saved
              * payment method.
              */
-            fun autoCollection(autoCollection: Boolean) = apply {
+            fun autoCollection(autoCollection: Boolean) =
+                autoCollection(JsonField.of(autoCollection))
+
+            /**
+             * Whether the credits purchase invoice should auto collect with the customer's saved
+             * payment method.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
                 this.autoCollection = autoCollection
             }
 
@@ -553,36 +781,37 @@ constructor(
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0.
              */
-            fun netTerms(netTerms: Long) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String?) = apply { this.memo = memo }
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
-            /**
-             * If true, new credit blocks created by this top-up will require that the corresponding
-             * invoice is paid before they can be drawn down from.
-             */
-            fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean?) = apply {
-                this.requireSuccessfulPayment = requireSuccessfulPayment
-            }
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: JsonField<String>) = apply { this.memo = memo }
 
             /**
              * If true, new credit blocks created by this top-up will require that the corresponding
              * invoice is paid before they can be drawn down from.
              */
             fun requireSuccessfulPayment(requireSuccessfulPayment: Boolean) =
-                requireSuccessfulPayment(requireSuccessfulPayment as Boolean?)
+                requireSuccessfulPayment(JsonField.of(requireSuccessfulPayment))
 
             /**
              * If true, new credit blocks created by this top-up will require that the corresponding
              * invoice is paid before they can be drawn down from.
              */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun requireSuccessfulPayment(requireSuccessfulPayment: Optional<Boolean>) =
-                requireSuccessfulPayment(requireSuccessfulPayment.orElse(null) as Boolean?)
+            fun requireSuccessfulPayment(requireSuccessfulPayment: JsonField<Boolean>) = apply {
+                this.requireSuccessfulPayment = requireSuccessfulPayment
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateResponse.kt
index 914d16d6..f60627af 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpCreateResponse.kt
@@ -81,37 +81,45 @@ private constructor(
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
         Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The amount to increment when the threshold is reached. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /**
      * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
      * it must match the customer's invoicing currency.
      */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /** Settings for invoices generated by triggered top-ups. */
-    @JsonProperty("invoice_settings") @ExcludeMissing fun _invoiceSettings() = invoiceSettings
+    @JsonProperty("invoice_settings")
+    @ExcludeMissing
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
     /** How much, in the customer's currency, to charge for each unit. */
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
     /**
      * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
      * the top-up will be triggered.
      */
-    @JsonProperty("threshold") @ExcludeMissing fun _threshold() = threshold
+    @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
     /**
      * The number of days or months after which the top-up expires. If unspecified, it does not
      * expire.
      */
-    @JsonProperty("expires_after") @ExcludeMissing fun _expiresAfter() = expiresAfter
+    @JsonProperty("expires_after")
+    @ExcludeMissing
+    fun _expiresAfter(): JsonField<Long> = expiresAfter
 
     /** The unit of expires_after. */
-    @JsonProperty("expires_after_unit") @ExcludeMissing fun _expiresAfterUnit() = expiresAfterUnit
+    @JsonProperty("expires_after_unit")
+    @ExcludeMissing
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -142,12 +150,12 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var threshold: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amount: JsonField<String>? = null
+        private var currency: JsonField<String>? = null
+        private var invoiceSettings: JsonField<InvoiceSettings>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var threshold: JsonField<String>? = null
         private var expiresAfter: JsonField<Long> = JsonMissing.of()
         private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -223,7 +231,21 @@ private constructor(
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
-        fun expiresAfter(expiresAfter: Long) = expiresAfter(JsonField.of(expiresAfter))
+        fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: Long) = expiresAfter(expiresAfter as Long?)
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun expiresAfter(expiresAfter: Optional<Long>) =
+            expiresAfter(expiresAfter.orElse(null) as Long?)
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
@@ -232,8 +254,12 @@ private constructor(
         fun expiresAfter(expiresAfter: JsonField<Long>) = apply { this.expiresAfter = expiresAfter }
 
         /** The unit of expires_after. */
-        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit) =
-            expiresAfterUnit(JsonField.of(expiresAfterUnit))
+        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+            expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
+            expiresAfterUnit(expiresAfterUnit.orElse(null))
 
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
@@ -261,12 +287,12 @@ private constructor(
 
         fun build(): CustomerCreditTopUpCreateResponse =
             CustomerCreditTopUpCreateResponse(
-                id,
-                amount,
-                currency,
-                invoiceSettings,
-                perUnitCostBasis,
-                threshold,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(invoiceSettings) { "`invoiceSettings` is required but was not set" },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(threshold) { "`threshold` is required but was not set" },
                 expiresAfter,
                 expiresAfterUnit,
                 additionalProperties.toImmutable(),
@@ -320,16 +346,18 @@ private constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
@@ -337,7 +365,7 @@ private constructor(
          */
         @JsonProperty("require_successful_payment")
         @ExcludeMissing
-        fun _requireSuccessfulPayment() = requireSuccessfulPayment
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -364,8 +392,8 @@ private constructor(
 
         class Builder {
 
-            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
             private var memo: JsonField<String> = JsonMissing.of()
             private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -407,7 +435,10 @@ private constructor(
             fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -448,8 +479,8 @@ private constructor(
 
             fun build(): InvoiceSettings =
                 InvoiceSettings(
-                    autoCollection,
-                    netTerms,
+                    checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                    checkNotNull(netTerms) { "`netTerms` is required but was not set" },
                     memo,
                     requireSuccessfulPayment,
                     additionalProperties.toImmutable(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteByExternalIdParams.kt
index c0113576..dca573a5 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteByExternalIdParams.kt
@@ -10,6 +10,7 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/** Delete top-up by external ID */
 class CustomerCreditTopUpDeleteByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteParams.kt
index 76e318bf..b62ea533 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpDeleteParams.kt
@@ -10,6 +10,7 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/** Delete top-up */
 class CustomerCreditTopUpDeleteParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdParams.kt
index 15040e73..8908293c 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdParams.kt
@@ -8,6 +8,7 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/** List top-ups by external ID */
 class CustomerCreditTopUpListByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdResponse.kt
index 952e4837..58eba3f0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListByExternalIdResponse.kt
@@ -81,37 +81,45 @@ private constructor(
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
         Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The amount to increment when the threshold is reached. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /**
      * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
      * it must match the customer's invoicing currency.
      */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /** Settings for invoices generated by triggered top-ups. */
-    @JsonProperty("invoice_settings") @ExcludeMissing fun _invoiceSettings() = invoiceSettings
+    @JsonProperty("invoice_settings")
+    @ExcludeMissing
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
     /** How much, in the customer's currency, to charge for each unit. */
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
     /**
      * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
      * the top-up will be triggered.
      */
-    @JsonProperty("threshold") @ExcludeMissing fun _threshold() = threshold
+    @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
     /**
      * The number of days or months after which the top-up expires. If unspecified, it does not
      * expire.
      */
-    @JsonProperty("expires_after") @ExcludeMissing fun _expiresAfter() = expiresAfter
+    @JsonProperty("expires_after")
+    @ExcludeMissing
+    fun _expiresAfter(): JsonField<Long> = expiresAfter
 
     /** The unit of expires_after. */
-    @JsonProperty("expires_after_unit") @ExcludeMissing fun _expiresAfterUnit() = expiresAfterUnit
+    @JsonProperty("expires_after_unit")
+    @ExcludeMissing
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -142,12 +150,12 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var threshold: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amount: JsonField<String>? = null
+        private var currency: JsonField<String>? = null
+        private var invoiceSettings: JsonField<InvoiceSettings>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var threshold: JsonField<String>? = null
         private var expiresAfter: JsonField<Long> = JsonMissing.of()
         private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -224,7 +232,21 @@ private constructor(
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
-        fun expiresAfter(expiresAfter: Long) = expiresAfter(JsonField.of(expiresAfter))
+        fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: Long) = expiresAfter(expiresAfter as Long?)
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun expiresAfter(expiresAfter: Optional<Long>) =
+            expiresAfter(expiresAfter.orElse(null) as Long?)
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
@@ -233,8 +255,12 @@ private constructor(
         fun expiresAfter(expiresAfter: JsonField<Long>) = apply { this.expiresAfter = expiresAfter }
 
         /** The unit of expires_after. */
-        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit) =
-            expiresAfterUnit(JsonField.of(expiresAfterUnit))
+        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+            expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
+            expiresAfterUnit(expiresAfterUnit.orElse(null))
 
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
@@ -262,12 +288,12 @@ private constructor(
 
         fun build(): CustomerCreditTopUpListByExternalIdResponse =
             CustomerCreditTopUpListByExternalIdResponse(
-                id,
-                amount,
-                currency,
-                invoiceSettings,
-                perUnitCostBasis,
-                threshold,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(invoiceSettings) { "`invoiceSettings` is required but was not set" },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(threshold) { "`threshold` is required but was not set" },
                 expiresAfter,
                 expiresAfterUnit,
                 additionalProperties.toImmutable(),
@@ -321,16 +347,18 @@ private constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
@@ -338,7 +366,7 @@ private constructor(
          */
         @JsonProperty("require_successful_payment")
         @ExcludeMissing
-        fun _requireSuccessfulPayment() = requireSuccessfulPayment
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -365,8 +393,8 @@ private constructor(
 
         class Builder {
 
-            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
             private var memo: JsonField<String> = JsonMissing.of()
             private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -408,7 +436,10 @@ private constructor(
             fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -449,8 +480,8 @@ private constructor(
 
             fun build(): InvoiceSettings =
                 InvoiceSettings(
-                    autoCollection,
-                    netTerms,
+                    checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                    checkNotNull(netTerms) { "`netTerms` is required but was not set" },
                     memo,
                     requireSuccessfulPayment,
                     additionalProperties.toImmutable(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListParams.kt
index 463a12d2..028efb01 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListParams.kt
@@ -8,6 +8,7 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/** List top-ups */
 class CustomerCreditTopUpListParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListResponse.kt
index 1822b168..d229bc4e 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerCreditTopUpListResponse.kt
@@ -81,37 +81,45 @@ private constructor(
     fun expiresAfterUnit(): Optional<ExpiresAfterUnit> =
         Optional.ofNullable(expiresAfterUnit.getNullable("expires_after_unit"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The amount to increment when the threshold is reached. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /**
      * The currency or custom pricing unit to use for this top-up. If this is a real-world currency,
      * it must match the customer's invoicing currency.
      */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /** Settings for invoices generated by triggered top-ups. */
-    @JsonProperty("invoice_settings") @ExcludeMissing fun _invoiceSettings() = invoiceSettings
+    @JsonProperty("invoice_settings")
+    @ExcludeMissing
+    fun _invoiceSettings(): JsonField<InvoiceSettings> = invoiceSettings
 
     /** How much, in the customer's currency, to charge for each unit. */
-    @JsonProperty("per_unit_cost_basis") @ExcludeMissing fun _perUnitCostBasis() = perUnitCostBasis
+    @JsonProperty("per_unit_cost_basis")
+    @ExcludeMissing
+    fun _perUnitCostBasis(): JsonField<String> = perUnitCostBasis
 
     /**
      * The threshold at which to trigger the top-up. If the balance is at or below this threshold,
      * the top-up will be triggered.
      */
-    @JsonProperty("threshold") @ExcludeMissing fun _threshold() = threshold
+    @JsonProperty("threshold") @ExcludeMissing fun _threshold(): JsonField<String> = threshold
 
     /**
      * The number of days or months after which the top-up expires. If unspecified, it does not
      * expire.
      */
-    @JsonProperty("expires_after") @ExcludeMissing fun _expiresAfter() = expiresAfter
+    @JsonProperty("expires_after")
+    @ExcludeMissing
+    fun _expiresAfter(): JsonField<Long> = expiresAfter
 
     /** The unit of expires_after. */
-    @JsonProperty("expires_after_unit") @ExcludeMissing fun _expiresAfterUnit() = expiresAfterUnit
+    @JsonProperty("expires_after_unit")
+    @ExcludeMissing
+    fun _expiresAfterUnit(): JsonField<ExpiresAfterUnit> = expiresAfterUnit
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -142,12 +150,12 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var invoiceSettings: JsonField<InvoiceSettings> = JsonMissing.of()
-        private var perUnitCostBasis: JsonField<String> = JsonMissing.of()
-        private var threshold: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amount: JsonField<String>? = null
+        private var currency: JsonField<String>? = null
+        private var invoiceSettings: JsonField<InvoiceSettings>? = null
+        private var perUnitCostBasis: JsonField<String>? = null
+        private var threshold: JsonField<String>? = null
         private var expiresAfter: JsonField<Long> = JsonMissing.of()
         private var expiresAfterUnit: JsonField<ExpiresAfterUnit> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -223,7 +231,21 @@ private constructor(
          * The number of days or months after which the top-up expires. If unspecified, it does not
          * expire.
          */
-        fun expiresAfter(expiresAfter: Long) = expiresAfter(JsonField.of(expiresAfter))
+        fun expiresAfter(expiresAfter: Long?) = expiresAfter(JsonField.ofNullable(expiresAfter))
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        fun expiresAfter(expiresAfter: Long) = expiresAfter(expiresAfter as Long?)
+
+        /**
+         * The number of days or months after which the top-up expires. If unspecified, it does not
+         * expire.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun expiresAfter(expiresAfter: Optional<Long>) =
+            expiresAfter(expiresAfter.orElse(null) as Long?)
 
         /**
          * The number of days or months after which the top-up expires. If unspecified, it does not
@@ -232,8 +254,12 @@ private constructor(
         fun expiresAfter(expiresAfter: JsonField<Long>) = apply { this.expiresAfter = expiresAfter }
 
         /** The unit of expires_after. */
-        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit) =
-            expiresAfterUnit(JsonField.of(expiresAfterUnit))
+        fun expiresAfterUnit(expiresAfterUnit: ExpiresAfterUnit?) =
+            expiresAfterUnit(JsonField.ofNullable(expiresAfterUnit))
+
+        /** The unit of expires_after. */
+        fun expiresAfterUnit(expiresAfterUnit: Optional<ExpiresAfterUnit>) =
+            expiresAfterUnit(expiresAfterUnit.orElse(null))
 
         /** The unit of expires_after. */
         fun expiresAfterUnit(expiresAfterUnit: JsonField<ExpiresAfterUnit>) = apply {
@@ -261,12 +287,12 @@ private constructor(
 
         fun build(): CustomerCreditTopUpListResponse =
             CustomerCreditTopUpListResponse(
-                id,
-                amount,
-                currency,
-                invoiceSettings,
-                perUnitCostBasis,
-                threshold,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(invoiceSettings) { "`invoiceSettings` is required but was not set" },
+                checkNotNull(perUnitCostBasis) { "`perUnitCostBasis` is required but was not set" },
+                checkNotNull(threshold) { "`threshold` is required but was not set" },
                 expiresAfter,
                 expiresAfterUnit,
                 additionalProperties.toImmutable(),
@@ -320,16 +346,18 @@ private constructor(
          * Whether the credits purchase invoice should auto collect with the customer's saved
          * payment method.
          */
-        @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /** An optional memo to display on the invoice. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
         /**
          * If true, new credit blocks created by this top-up will require that the corresponding
@@ -337,7 +365,7 @@ private constructor(
          */
         @JsonProperty("require_successful_payment")
         @ExcludeMissing
-        fun _requireSuccessfulPayment() = requireSuccessfulPayment
+        fun _requireSuccessfulPayment(): JsonField<Boolean> = requireSuccessfulPayment
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -364,8 +392,8 @@ private constructor(
 
         class Builder {
 
-            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean>? = null
+            private var netTerms: JsonField<Long>? = null
             private var memo: JsonField<String> = JsonMissing.of()
             private var requireSuccessfulPayment: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -407,7 +435,10 @@ private constructor(
             fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /** An optional memo to display on the invoice. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo to display on the invoice. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo to display on the invoice. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -448,8 +479,8 @@ private constructor(
 
             fun build(): InvoiceSettings =
                 InvoiceSettings(
-                    autoCollection,
-                    netTerms,
+                    checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                    checkNotNull(netTerms) { "`netTerms` is required but was not set" },
                     memo,
                     requireSuccessfulPayment,
                     additionalProperties.toImmutable(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerDeleteParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerDeleteParams.kt
index 63ecd62c..14241f42 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerDeleteParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerDeleteParams.kt
@@ -10,6 +10,20 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This performs a deletion of this customer, its subscriptions, and its invoices, provided the
+ * customer does not have any issued invoices. Customers with issued invoices cannot be deleted.
+ * This operation is irreversible. Note that this is a _soft_ deletion, but the data will be
+ * inaccessible through the API and Orb dashboard. For a hard-deletion, please reach out to the Orb
+ * team directly.
+ *
+ * **Note**: This operation happens asynchronously and can be expected to take a few minutes to
+ * propagate to related resources. However, querying for the customer on subsequent GET requests
+ * while deletion is in process will reflect its deletion with a `deleted: true` property. Once the
+ * customer deletion has been fully processed, the customer will not be returned in the API.
+ *
+ * On successful processing, this returns an empty dictionary (`{}`) in the API.
+ */
 class CustomerDeleteParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchByExternalIdParams.kt
index c08aec62..37ad269c 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchByExternalIdParams.kt
@@ -7,6 +7,13 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch customer details given an `external_customer_id` (see
+ * [Customer ID Aliases](../guides/events-and-metrics/customer-aliases)).
+ *
+ * Note that the resource and semantics of this endpoint exactly mirror
+ * [Get Customer](fetch-customer).
+ */
 class CustomerFetchByExternalIdParams
 constructor(
     private val externalCustomerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchParams.kt
index 854ccfbc..e486a4a2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerFetchParams.kt
@@ -7,6 +7,13 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch customer details given an identifier. If the `Customer` is in the
+ * process of being deleted, only the properties `id` and `deleted: true` will be returned.
+ *
+ * See the [Customer resource](../guides/core-concepts.mdx#customer) for a full discussion of the
+ * Customer model.
+ */
 class CustomerFetchParams
 constructor(
     private val customerId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerListParams.kt
index 376b6f2e..f95e2248 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerListParams.kt
@@ -10,6 +10,13 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all customers for an account. The list of customers is ordered
+ * starting from the most recently created customer. This endpoint follows Orb's
+ * [standardized pagination format](../reference/pagination).
+ *
+ * See [Customer](../guides/concepts#customer) for an overview of the customer model.
+ */
 class CustomerListParams
 constructor(
     private val createdAtGt: OffsetDateTime?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateByExternalIdParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateByExternalIdParams.kt
index 2b6ff818..e2583cf4 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateByExternalIdParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateByExternalIdParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,11 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint is used to update customer details given an `external_customer_id` (see
+ * [Customer ID Aliases](../guides/events-and-metrics/customer-aliases)). Note that the resource and
+ * semantics of this endpoint exactly mirror [Update Customer](update-customer).
+ */
 class CustomerUpdateByExternalIdParams
 constructor(
     private val id: String,
@@ -214,12 +220,187 @@ constructor(
      */
     fun taxId(): Optional<TaxId> = body.taxId()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+        body._accountingSyncConfiguration()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Additional email addresses for this customer. If populated, these email addresses will be
+     * CC'd for customer communications.
+     */
+    fun _additionalEmails(): JsonField<List<String>> = body._additionalEmails()
+
+    /**
+     * Used to determine if invoices for this customer will automatically attempt to charge a saved
+     * payment method, if available. This parameter defaults to `True` when a payment provider is
+     * provided on customer creation.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
+
+    fun _billingAddress(): JsonField<BillingAddress> = body._billingAddress()
+
+    /**
+     * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+     * creation time, will be set at subscription creation time.
+     */
+    fun _currency(): JsonField<String> = body._currency()
+
+    /** A valid customer email, to be used for invoicing and notifications. */
+    fun _email(): JsonField<String> = body._email()
+
+    fun _emailDelivery(): JsonField<Boolean> = body._emailDelivery()
+
+    /**
+     * The external customer ID. This can only be set if empty and the customer has no past or
+     * current subscriptions.
+     */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /** The full name of the customer */
+    fun _name(): JsonField<String> = body._name()
+
+    /**
+     * This is used for creating charges or invoices in an external system via Orb. When not in test
+     * mode:
+     * - the connection must first be configured in the Orb webapp.
+     * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+     *   `netsuite`), any product mappings must first be configured with the Orb team.
+     */
+    fun _paymentProvider(): JsonField<PaymentProvider> = body._paymentProvider()
+
+    /**
+     * The ID of this customer in an external payments solution, such as Stripe. This is used for
+     * creating charges or invoices in the external system via Orb.
+     */
+    fun _paymentProviderId(): JsonField<String> = body._paymentProviderId()
+
+    fun _reportingConfiguration(): JsonField<ReportingConfiguration> =
+        body._reportingConfiguration()
+
+    fun _shippingAddress(): JsonField<ShippingAddress> = body._shippingAddress()
+
+    fun _taxConfiguration(): JsonField<TaxConfiguration> = body._taxConfiguration()
+
+    /**
+     * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
+     * headers of invoices.
+     *
+     * ### Supported Tax ID Countries and Types
+     * |Country             |Type        |Description                                                                                            |
+     * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+     * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+     * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+     * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+     * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+     * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+     * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+     * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+     * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+     * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+     * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+     * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+     * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+     * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+     * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+     * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+     * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+     * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+     * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+     * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+     * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+     * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+     * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+     * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+     * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+     * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+     * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |France              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+     * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+     * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+     * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+     * |India               |`in_gst`    |Indian GST Number                                                                                      |
+     * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+     * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+     * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+     * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+     * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+     * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+     * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+     * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+     * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+     * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+     * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+     * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+     * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+     * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+     * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+     * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+     * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+     * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+     * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+     * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+     * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+     * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+     * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+     * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+     * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+     * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+     * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+     * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+     * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+     * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+     * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+     * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+     * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+     * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+     * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+     * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+     * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+     * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+     * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+     * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+     * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+     * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+     * |United States       |`us_ein`    |United States EIN                                                                                      |
+     * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+     * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+     * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+     */
+    fun _taxId(): JsonField<TaxId> = body._taxId()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerUpdateByExternalIdBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -238,37 +419,256 @@ constructor(
     @JsonCreator
     internal constructor(
         @JsonProperty("accounting_sync_configuration")
-        private val accountingSyncConfiguration: AccountingSyncConfiguration?,
-        @JsonProperty("additional_emails") private val additionalEmails: List<String>?,
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
-        @JsonProperty("billing_address") private val billingAddress: BillingAddress?,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("email") private val email: String?,
-        @JsonProperty("email_delivery") private val emailDelivery: Boolean?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("name") private val name: String?,
-        @JsonProperty("payment_provider") private val paymentProvider: PaymentProvider?,
-        @JsonProperty("payment_provider_id") private val paymentProviderId: String?,
+        @ExcludeMissing
+        private val accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("additional_emails")
+        @ExcludeMissing
+        private val additionalEmails: JsonField<List<String>> = JsonMissing.of(),
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_address")
+        @ExcludeMissing
+        private val billingAddress: JsonField<BillingAddress> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("email")
+        @ExcludeMissing
+        private val email: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("email_delivery")
+        @ExcludeMissing
+        private val emailDelivery: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("payment_provider")
+        @ExcludeMissing
+        private val paymentProvider: JsonField<PaymentProvider> = JsonMissing.of(),
+        @JsonProperty("payment_provider_id")
+        @ExcludeMissing
+        private val paymentProviderId: JsonField<String> = JsonMissing.of(),
         @JsonProperty("reporting_configuration")
-        private val reportingConfiguration: ReportingConfiguration?,
-        @JsonProperty("shipping_address") private val shippingAddress: ShippingAddress?,
-        @JsonProperty("tax_configuration") private val taxConfiguration: TaxConfiguration?,
-        @JsonProperty("tax_id") private val taxId: TaxId?,
+        @ExcludeMissing
+        private val reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of(),
+        @JsonProperty("shipping_address")
+        @ExcludeMissing
+        private val shippingAddress: JsonField<ShippingAddress> = JsonMissing.of(),
+        @JsonProperty("tax_configuration")
+        @ExcludeMissing
+        private val taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of(),
+        @JsonProperty("tax_id")
+        @ExcludeMissing
+        private val taxId: JsonField<TaxId> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
+            Optional.ofNullable(
+                accountingSyncConfiguration.getNullable("accounting_sync_configuration")
+            )
+
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(): Optional<List<String>> =
+            Optional.ofNullable(additionalEmails.getNullable("additional_emails"))
+
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        fun billingAddress(): Optional<BillingAddress> =
+            Optional.ofNullable(billingAddress.getNullable("billing_address"))
+
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /** A valid customer email, to be used for invoicing and notifications. */
+        fun email(): Optional<String> = Optional.ofNullable(email.getNullable("email"))
+
+        fun emailDelivery(): Optional<Boolean> =
+            Optional.ofNullable(emailDelivery.getNullable("email_delivery"))
+
+        /**
+         * The external customer ID. This can only be set if empty and the customer has no past or
+         * current subscriptions.
+         */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The full name of the customer */
+        fun name(): Optional<String> = Optional.ofNullable(name.getNullable("name"))
+
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode:
+         * - the connection must first be configured in the Orb webapp.
+         * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+         *   `netsuite`), any product mappings must first be configured with the Orb team.
+         */
+        fun paymentProvider(): Optional<PaymentProvider> =
+            Optional.ofNullable(paymentProvider.getNullable("payment_provider"))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(): Optional<String> =
+            Optional.ofNullable(paymentProviderId.getNullable("payment_provider_id"))
+
+        fun reportingConfiguration(): Optional<ReportingConfiguration> =
+            Optional.ofNullable(reportingConfiguration.getNullable("reporting_configuration"))
+
+        fun shippingAddress(): Optional<ShippingAddress> =
+            Optional.ofNullable(shippingAddress.getNullable("shipping_address"))
+
+        fun taxConfiguration(): Optional<TaxConfiguration> =
+            Optional.ofNullable(taxConfiguration.getNullable("tax_configuration"))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId.getNullable("tax_id"))
+
         @JsonProperty("accounting_sync_configuration")
-        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
-            Optional.ofNullable(accountingSyncConfiguration)
+        @ExcludeMissing
+        fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+            accountingSyncConfiguration
 
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
          */
         @JsonProperty("additional_emails")
-        fun additionalEmails(): Optional<List<String>> = Optional.ofNullable(additionalEmails)
+        @ExcludeMissing
+        fun _additionalEmails(): JsonField<List<String>> = additionalEmails
 
         /**
          * Used to determine if invoices for this customer will automatically attempt to charge a
@@ -276,39 +676,43 @@ constructor(
          * provider is provided on customer creation.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         @JsonProperty("billing_address")
-        fun billingAddress(): Optional<BillingAddress> = Optional.ofNullable(billingAddress)
+        @ExcludeMissing
+        fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** A valid customer email, to be used for invoicing and notifications. */
-        @JsonProperty("email") fun email(): Optional<String> = Optional.ofNullable(email)
+        @JsonProperty("email") @ExcludeMissing fun _email(): JsonField<String> = email
 
         @JsonProperty("email_delivery")
-        fun emailDelivery(): Optional<Boolean> = Optional.ofNullable(emailDelivery)
+        @ExcludeMissing
+        fun _emailDelivery(): JsonField<Boolean> = emailDelivery
 
         /**
          * The external customer ID. This can only be set if empty and the customer has no past or
          * current subscriptions.
          */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /** The full name of the customer */
-        @JsonProperty("name") fun name(): Optional<String> = Optional.ofNullable(name)
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
@@ -318,24 +722,28 @@ constructor(
          *   `netsuite`), any product mappings must first be configured with the Orb team.
          */
         @JsonProperty("payment_provider")
-        fun paymentProvider(): Optional<PaymentProvider> = Optional.ofNullable(paymentProvider)
+        @ExcludeMissing
+        fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
         @JsonProperty("payment_provider_id")
-        fun paymentProviderId(): Optional<String> = Optional.ofNullable(paymentProviderId)
+        @ExcludeMissing
+        fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
         @JsonProperty("reporting_configuration")
-        fun reportingConfiguration(): Optional<ReportingConfiguration> =
-            Optional.ofNullable(reportingConfiguration)
+        @ExcludeMissing
+        fun _reportingConfiguration(): JsonField<ReportingConfiguration> = reportingConfiguration
 
         @JsonProperty("shipping_address")
-        fun shippingAddress(): Optional<ShippingAddress> = Optional.ofNullable(shippingAddress)
+        @ExcludeMissing
+        fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
         @JsonProperty("tax_configuration")
-        fun taxConfiguration(): Optional<TaxConfiguration> = Optional.ofNullable(taxConfiguration)
+        @ExcludeMissing
+        fun _taxConfiguration(): JsonField<TaxConfiguration> = taxConfiguration
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -443,12 +851,36 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        @JsonProperty("tax_id") fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId)
+        @JsonProperty("tax_id") @ExcludeMissing fun _taxId(): JsonField<TaxId> = taxId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerUpdateByExternalIdBody = apply {
+            if (!validated) {
+                accountingSyncConfiguration().map { it.validate() }
+                additionalEmails()
+                autoCollection()
+                billingAddress().map { it.validate() }
+                currency()
+                email()
+                emailDelivery()
+                externalCustomerId()
+                metadata().map { it.validate() }
+                name()
+                paymentProvider()
+                paymentProviderId()
+                reportingConfiguration().map { it.validate() }
+                shippingAddress().map { it.validate() }
+                taxConfiguration()
+                taxId().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -458,22 +890,23 @@ constructor(
 
         class Builder {
 
-            private var accountingSyncConfiguration: AccountingSyncConfiguration? = null
-            private var additionalEmails: MutableList<String>? = null
-            private var autoCollection: Boolean? = null
-            private var billingAddress: BillingAddress? = null
-            private var currency: String? = null
-            private var email: String? = null
-            private var emailDelivery: Boolean? = null
-            private var externalCustomerId: String? = null
-            private var metadata: Metadata? = null
-            private var name: String? = null
-            private var paymentProvider: PaymentProvider? = null
-            private var paymentProviderId: String? = null
-            private var reportingConfiguration: ReportingConfiguration? = null
-            private var shippingAddress: ShippingAddress? = null
-            private var taxConfiguration: TaxConfiguration? = null
-            private var taxId: TaxId? = null
+            private var accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+                JsonMissing.of()
+            private var additionalEmails: JsonField<MutableList<String>>? = null
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var email: JsonField<String> = JsonMissing.of()
+            private var emailDelivery: JsonField<Boolean> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var name: JsonField<String> = JsonMissing.of()
+            private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
+            private var paymentProviderId: JsonField<String> = JsonMissing.of()
+            private var reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of()
+            private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
+            private var taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of()
+            private var taxId: JsonField<TaxId> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -482,7 +915,7 @@ constructor(
                     accountingSyncConfiguration =
                         customerUpdateByExternalIdBody.accountingSyncConfiguration
                     additionalEmails =
-                        customerUpdateByExternalIdBody.additionalEmails?.toMutableList()
+                        customerUpdateByExternalIdBody.additionalEmails.map { it.toMutableList() }
                     autoCollection = customerUpdateByExternalIdBody.autoCollection
                     billingAddress = customerUpdateByExternalIdBody.billingAddress
                     currency = customerUpdateByExternalIdBody.currency
@@ -503,19 +936,22 @@ constructor(
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: AccountingSyncConfiguration?
-            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+            ) = accountingSyncConfiguration(JsonField.ofNullable(accountingSyncConfiguration))
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
             ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+            fun accountingSyncConfiguration(
+                accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
-            fun additionalEmails(additionalEmails: List<String>?) = apply {
-                this.additionalEmails = additionalEmails?.toMutableList()
-            }
+            fun additionalEmails(additionalEmails: List<String>?) =
+                additionalEmails(JsonField.ofNullable(additionalEmails))
 
             /**
              * Additional email addresses for this customer. If populated, these email addresses
@@ -524,13 +960,29 @@ constructor(
             fun additionalEmails(additionalEmails: Optional<List<String>>) =
                 additionalEmails(additionalEmails.orElse(null))
 
+            /**
+             * Additional email addresses for this customer. If populated, these email addresses
+             * will be CC'd for customer communications.
+             */
+            fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+                this.additionalEmails = additionalEmails.map { it.toMutableList() }
+            }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
             fun addAdditionalEmail(additionalEmail: String) = apply {
                 additionalEmails =
-                    (additionalEmails ?: mutableListOf()).apply { add(additionalEmail) }
+                    (additionalEmails ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(additionalEmail)
+                    }
             }
 
             /**
@@ -538,9 +990,8 @@ constructor(
              * a saved payment method, if available. This parameter defaults to `True` when a
              * payment provider is provided on customer creation.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Used to determine if invoices for this customer will automatically attempt to charge
@@ -558,18 +1009,30 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
-            fun billingAddress(billingAddress: BillingAddress?) = apply {
-                this.billingAddress = billingAddress
+            /**
+             * Used to determine if invoices for this customer will automatically attempt to charge
+             * a saved payment method, if available. This parameter defaults to `True` when a
+             * payment provider is provided on customer creation.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
             }
 
+            fun billingAddress(billingAddress: BillingAddress?) =
+                billingAddress(JsonField.ofNullable(billingAddress))
+
             fun billingAddress(billingAddress: Optional<BillingAddress>) =
                 billingAddress(billingAddress.orElse(null))
 
+            fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+                this.billingAddress = billingAddress
+            }
+
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
              * at creation time, will be set at subscription creation time.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
@@ -577,15 +1040,23 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * An ISO 4217 currency string used for the customer's invoices and balance. If not set
+             * at creation time, will be set at subscription creation time.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /** A valid customer email, to be used for invoicing and notifications. */
-            fun email(email: String?) = apply { this.email = email }
+            fun email(email: String?) = email(JsonField.ofNullable(email))
 
             /** A valid customer email, to be used for invoicing and notifications. */
             fun email(email: Optional<String>) = email(email.orElse(null))
 
-            fun emailDelivery(emailDelivery: Boolean?) = apply {
-                this.emailDelivery = emailDelivery
-            }
+            /** A valid customer email, to be used for invoicing and notifications. */
+            fun email(email: JsonField<String>) = apply { this.email = email }
+
+            fun emailDelivery(emailDelivery: Boolean?) =
+                emailDelivery(JsonField.ofNullable(emailDelivery))
 
             fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
 
@@ -593,13 +1064,16 @@ constructor(
             fun emailDelivery(emailDelivery: Optional<Boolean>) =
                 emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+            fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+                this.emailDelivery = emailDelivery
+            }
+
             /**
              * The external customer ID. This can only be set if empty and the customer has no past
              * or current subscriptions.
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * The external customer ID. This can only be set if empty and the customer has no past
@@ -608,12 +1082,20 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * The external customer ID. This can only be set if empty and the customer has no past
+             * or current subscriptions.
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -622,12 +1104,22 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /** The full name of the customer */
-            fun name(name: String?) = apply { this.name = name }
+            fun name(name: String?) = name(JsonField.ofNullable(name))
 
             /** The full name of the customer */
             fun name(name: Optional<String>) = name(name.orElse(null))
 
+            /** The full name of the customer */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
              * in test mode:
@@ -636,9 +1128,8 @@ constructor(
              *   `bill.com`, `netsuite`), any product mappings must first be configured with the Orb
              *   team.
              */
-            fun paymentProvider(paymentProvider: PaymentProvider?) = apply {
-                this.paymentProvider = paymentProvider
-            }
+            fun paymentProvider(paymentProvider: PaymentProvider?) =
+                paymentProvider(JsonField.ofNullable(paymentProvider))
 
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
@@ -651,54 +1142,188 @@ constructor(
             fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
                 paymentProvider(paymentProvider.orElse(null))
 
+            /**
+             * This is used for creating charges or invoices in an external system via Orb. When not
+             * in test mode:
+             * - the connection must first be configured in the Orb webapp.
+             * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`,
+             *   `bill.com`, `netsuite`), any product mappings must first be configured with the Orb
+             *   team.
+             */
+            fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+                this.paymentProvider = paymentProvider
+            }
+
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: String?) = apply {
-                this.paymentProviderId = paymentProviderId
-            }
+            fun paymentProviderId(paymentProviderId: String?) =
+                paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+            /**
+             * The ID of this customer in an external payments solution, such as Stripe. This is
+             * used for creating charges or invoices in the external system via Orb.
+             */
+            fun paymentProviderId(paymentProviderId: Optional<String>) =
+                paymentProviderId(paymentProviderId.orElse(null))
 
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: Optional<String>) =
-                paymentProviderId(paymentProviderId.orElse(null))
-
-            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-                this.reportingConfiguration = reportingConfiguration
-            }
-
-            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-                reportingConfiguration(reportingConfiguration.orElse(null))
-
-            fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-                this.shippingAddress = shippingAddress
-            }
-
-            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-                shippingAddress(shippingAddress.orElse(null))
-
-            fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-                this.taxConfiguration = taxConfiguration
-            }
-
-            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-                taxConfiguration(taxConfiguration.orElse(null))
-
-            fun taxConfiguration(
-                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-            ) = apply {
-                this.taxConfiguration =
-                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
-            }
-
-            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-                apply {
-                    this.taxConfiguration =
-                        TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration)
-                }
+            fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+                this.paymentProviderId = paymentProviderId
+            }
+
+            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) =
+                reportingConfiguration(JsonField.ofNullable(reportingConfiguration))
+
+            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+                reportingConfiguration(reportingConfiguration.orElse(null))
+
+            fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+                apply {
+                    this.reportingConfiguration = reportingConfiguration
+                }
+
+            fun shippingAddress(shippingAddress: ShippingAddress?) =
+                shippingAddress(JsonField.ofNullable(shippingAddress))
+
+            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+                shippingAddress(shippingAddress.orElse(null))
+
+            fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+                this.shippingAddress = shippingAddress
+            }
+
+            fun taxConfiguration(taxConfiguration: TaxConfiguration?) =
+                taxConfiguration(JsonField.ofNullable(taxConfiguration))
+
+            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+                taxConfiguration(taxConfiguration.orElse(null))
+
+            fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+                this.taxConfiguration = taxConfiguration
+            }
+
+            fun taxConfiguration(
+                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+            ) =
+                taxConfiguration(
+                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
+                )
+
+            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+                taxConfiguration(TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration))
+
+            /**
+             * Tax IDs are commonly required to be displayed on customer invoices, which are added
+             * to the headers of invoices.
+             *
+             * ### Supported Tax ID Countries and Types
+             * |Country             |Type        |Description                                                                                            |
+             * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+             * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+             * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+             * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+             * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+             * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+             * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+             * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+             * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+             * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+             * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+             * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+             * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+             * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+             * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+             * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+             * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+             * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+             * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+             * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+             * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+             * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+             * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+             * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+             * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+             * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+             * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |France              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+             * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+             * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+             * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+             * |India               |`in_gst`    |Indian GST Number                                                                                      |
+             * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+             * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+             * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+             * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+             * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+             * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+             * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+             * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+             * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+             * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+             * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+             * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+             * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+             * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+             * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+             * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+             * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+             * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+             * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+             * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+             * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+             * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+             * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+             * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+             * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+             * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+             * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+             * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+             * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+             * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+             * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+             * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+             * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+             * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+             * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+             * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+             * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+             * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+             * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+             * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+             * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+             * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+             * |United States       |`us_ein`    |United States EIN                                                                                      |
+             * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+             * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+             * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+             */
+            fun taxId(taxId: TaxId?) = taxId(JsonField.ofNullable(taxId))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -806,7 +1431,7 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: TaxId?) = apply { this.taxId = taxId }
+            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -914,7 +1539,7 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+            fun taxId(taxId: JsonField<TaxId>) = apply { this.taxId = taxId }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -938,7 +1563,7 @@ constructor(
             fun build(): CustomerUpdateByExternalIdBody =
                 CustomerUpdateByExternalIdBody(
                     accountingSyncConfiguration,
-                    additionalEmails?.toImmutable(),
+                    (additionalEmails ?: JsonMissing.of()).map { it.toImmutable() },
                     autoCollection,
                     billingAddress,
                     currency,
@@ -1012,6 +1637,10 @@ constructor(
             accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
         ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+        fun accountingSyncConfiguration(
+            accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+        ) = apply { body.accountingSyncConfiguration(accountingSyncConfiguration) }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1027,6 +1656,14 @@ constructor(
         fun additionalEmails(additionalEmails: Optional<List<String>>) =
             additionalEmails(additionalEmails.orElse(null))
 
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+            body.additionalEmails(additionalEmails)
+        }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1058,6 +1695,15 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         fun billingAddress(billingAddress: BillingAddress?) = apply {
             body.billingAddress(billingAddress)
         }
@@ -1065,6 +1711,10 @@ constructor(
         fun billingAddress(billingAddress: Optional<BillingAddress>) =
             billingAddress(billingAddress.orElse(null))
 
+        fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+            body.billingAddress(billingAddress)
+        }
+
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
@@ -1077,12 +1727,21 @@ constructor(
          */
         fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** A valid customer email, to be used for invoicing and notifications. */
         fun email(email: String?) = apply { body.email(email) }
 
         /** A valid customer email, to be used for invoicing and notifications. */
         fun email(email: Optional<String>) = email(email.orElse(null))
 
+        /** A valid customer email, to be used for invoicing and notifications. */
+        fun email(email: JsonField<String>) = apply { body.email(email) }
+
         fun emailDelivery(emailDelivery: Boolean?) = apply { body.emailDelivery(emailDelivery) }
 
         fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
@@ -1091,6 +1750,10 @@ constructor(
         fun emailDelivery(emailDelivery: Optional<Boolean>) =
             emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+        fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+            body.emailDelivery(emailDelivery)
+        }
+
         /**
          * The external customer ID. This can only be set if empty and the customer has no past or
          * current subscriptions.
@@ -1106,6 +1769,14 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /**
+         * The external customer ID. This can only be set if empty and the customer has no past or
+         * current subscriptions.
+         */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -1120,12 +1791,22 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /** The full name of the customer */
         fun name(name: String?) = apply { body.name(name) }
 
         /** The full name of the customer */
         fun name(name: Optional<String>) = name(name.orElse(null))
 
+        /** The full name of the customer */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
          * test mode:
@@ -1147,6 +1828,17 @@ constructor(
         fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
             paymentProvider(paymentProvider.orElse(null))
 
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode:
+         * - the connection must first be configured in the Orb webapp.
+         * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+         *   `netsuite`), any product mappings must first be configured with the Orb team.
+         */
+        fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+            body.paymentProvider(paymentProvider)
+        }
+
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
@@ -1159,38 +1851,167 @@ constructor(
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
-        fun paymentProviderId(paymentProviderId: Optional<String>) =
-            paymentProviderId(paymentProviderId.orElse(null))
-
-        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-            body.reportingConfiguration(reportingConfiguration)
-        }
-
-        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-            reportingConfiguration(reportingConfiguration.orElse(null))
-
-        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-            body.shippingAddress(shippingAddress)
-        }
-
-        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-            shippingAddress(shippingAddress.orElse(null))
-
-        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-            body.taxConfiguration(taxConfiguration)
-        }
-
-        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-            taxConfiguration(taxConfiguration.orElse(null))
-
-        fun taxConfiguration(
-            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
-
-        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-            apply {
-                body.taxConfiguration(newTaxJarConfiguration)
-            }
+        fun paymentProviderId(paymentProviderId: Optional<String>) =
+            paymentProviderId(paymentProviderId.orElse(null))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+            body.paymentProviderId(paymentProviderId)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
+            body.reportingConfiguration(reportingConfiguration)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+            reportingConfiguration(reportingConfiguration.orElse(null))
+
+        fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+            apply {
+                body.reportingConfiguration(reportingConfiguration)
+            }
+
+        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
+
+        fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+            taxConfiguration(taxConfiguration.orElse(null))
+
+        fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(
+            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
+
+        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+            apply {
+                body.taxConfiguration(newTaxJarConfiguration)
+            }
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1298,7 +2119,7 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
+        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1406,7 +2227,26 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+        fun taxId(taxId: JsonField<TaxId>) = apply { body.taxId(taxId) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -1506,25 +2346,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerUpdateByExternalIdParams =
             CustomerUpdateByExternalIdParams(
                 checkNotNull(id) { "`id` is required but was not set" },
@@ -1539,22 +2360,40 @@ constructor(
     @JsonCreator
     private constructor(
         @JsonProperty("accounting_providers")
-        private val accountingProviders: List<AccountingProvider>?,
-        @JsonProperty("excluded") private val excluded: Boolean?,
+        @ExcludeMissing
+        private val accountingProviders: JsonField<List<AccountingProvider>> = JsonMissing.of(),
+        @JsonProperty("excluded")
+        @ExcludeMissing
+        private val excluded: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("accounting_providers")
         fun accountingProviders(): Optional<List<AccountingProvider>> =
-            Optional.ofNullable(accountingProviders)
+            Optional.ofNullable(accountingProviders.getNullable("accounting_providers"))
+
+        fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded.getNullable("excluded"))
+
+        @JsonProperty("accounting_providers")
+        @ExcludeMissing
+        fun _accountingProviders(): JsonField<List<AccountingProvider>> = accountingProviders
 
-        @JsonProperty("excluded") fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded)
+        @JsonProperty("excluded") @ExcludeMissing fun _excluded(): JsonField<Boolean> = excluded
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AccountingSyncConfiguration = apply {
+            if (!validated) {
+                accountingProviders().map { it.forEach { it.validate() } }
+                excluded()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1564,38 +2403,52 @@ constructor(
 
         class Builder {
 
-            private var accountingProviders: MutableList<AccountingProvider>? = null
-            private var excluded: Boolean? = null
+            private var accountingProviders: JsonField<MutableList<AccountingProvider>>? = null
+            private var excluded: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(accountingSyncConfiguration: AccountingSyncConfiguration) = apply {
                 accountingProviders =
-                    accountingSyncConfiguration.accountingProviders?.toMutableList()
+                    accountingSyncConfiguration.accountingProviders.map { it.toMutableList() }
                 excluded = accountingSyncConfiguration.excluded
                 additionalProperties =
                     accountingSyncConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun accountingProviders(accountingProviders: List<AccountingProvider>?) = apply {
-                this.accountingProviders = accountingProviders?.toMutableList()
-            }
+            fun accountingProviders(accountingProviders: List<AccountingProvider>?) =
+                accountingProviders(JsonField.ofNullable(accountingProviders))
 
             fun accountingProviders(accountingProviders: Optional<List<AccountingProvider>>) =
                 accountingProviders(accountingProviders.orElse(null))
 
+            fun accountingProviders(accountingProviders: JsonField<List<AccountingProvider>>) =
+                apply {
+                    this.accountingProviders = accountingProviders.map { it.toMutableList() }
+                }
+
             fun addAccountingProvider(accountingProvider: AccountingProvider) = apply {
                 accountingProviders =
-                    (accountingProviders ?: mutableListOf()).apply { add(accountingProvider) }
+                    (accountingProviders ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(accountingProvider)
+                    }
             }
 
-            fun excluded(excluded: Boolean?) = apply { this.excluded = excluded }
+            fun excluded(excluded: Boolean?) = excluded(JsonField.ofNullable(excluded))
 
             fun excluded(excluded: Boolean) = excluded(excluded as Boolean?)
 
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun excluded(excluded: Optional<Boolean>) = excluded(excluded.orElse(null) as Boolean?)
 
+            fun excluded(excluded: JsonField<Boolean>) = apply { this.excluded = excluded }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1617,7 +2470,7 @@ constructor(
 
             fun build(): AccountingSyncConfiguration =
                 AccountingSyncConfiguration(
-                    accountingProviders?.toImmutable(),
+                    (accountingProviders ?: JsonMissing.of()).map { it.toImmutable() },
                     excluded,
                     additionalProperties.toImmutable(),
                 )
@@ -1627,21 +2480,43 @@ constructor(
         class AccountingProvider
         @JsonCreator
         private constructor(
-            @JsonProperty("external_provider_id") private val externalProviderId: String,
-            @JsonProperty("provider_type") private val providerType: String,
+            @JsonProperty("external_provider_id")
+            @ExcludeMissing
+            private val externalProviderId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            private val providerType: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
+            fun externalProviderId(): String =
+                externalProviderId.getRequired("external_provider_id")
+
+            fun providerType(): String = providerType.getRequired("provider_type")
+
             @JsonProperty("external_provider_id")
-            fun externalProviderId(): String = externalProviderId
+            @ExcludeMissing
+            fun _externalProviderId(): JsonField<String> = externalProviderId
 
-            @JsonProperty("provider_type") fun providerType(): String = providerType
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            fun _providerType(): JsonField<String> = providerType
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): AccountingProvider = apply {
+                if (!validated) {
+                    externalProviderId()
+                    providerType()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1651,8 +2526,8 @@ constructor(
 
             class Builder {
 
-                private var externalProviderId: String? = null
-                private var providerType: String? = null
+                private var externalProviderId: JsonField<String>? = null
+                private var providerType: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1662,11 +2537,18 @@ constructor(
                     additionalProperties = accountingProvider.additionalProperties.toMutableMap()
                 }
 
-                fun externalProviderId(externalProviderId: String) = apply {
+                fun externalProviderId(externalProviderId: String) =
+                    externalProviderId(JsonField.of(externalProviderId))
+
+                fun externalProviderId(externalProviderId: JsonField<String>) = apply {
                     this.externalProviderId = externalProviderId
                 }
 
-                fun providerType(providerType: String) = apply { this.providerType = providerType }
+                fun providerType(providerType: String) = providerType(JsonField.of(providerType))
+
+                fun providerType(providerType: JsonField<String>) = apply {
+                    this.providerType = providerType
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1740,33 +2622,73 @@ constructor(
     class BillingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
+
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
+
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): BillingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1776,12 +2698,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1795,30 +2717,42 @@ constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1885,6 +2819,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2019,17 +2961,30 @@ constructor(
     class ReportingConfiguration
     @JsonCreator
     private constructor(
-        @JsonProperty("exempt") private val exempt: Boolean,
+        @JsonProperty("exempt")
+        @ExcludeMissing
+        private val exempt: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("exempt") fun exempt(): Boolean = exempt
+        fun exempt(): Boolean = exempt.getRequired("exempt")
+
+        @JsonProperty("exempt") @ExcludeMissing fun _exempt(): JsonField<Boolean> = exempt
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReportingConfiguration = apply {
+            if (!validated) {
+                exempt()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2039,7 +2994,7 @@ constructor(
 
         class Builder {
 
-            private var exempt: Boolean? = null
+            private var exempt: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2048,7 +3003,9 @@ constructor(
                 additionalProperties = reportingConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun exempt(exempt: Boolean) = apply { this.exempt = exempt }
+            fun exempt(exempt: Boolean) = exempt(JsonField.of(exempt))
+
+            fun exempt(exempt: JsonField<Boolean>) = apply { this.exempt = exempt }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -2098,33 +3055,73 @@ constructor(
     class ShippingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
+
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
+
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ShippingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2134,12 +3131,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2153,30 +3150,42 @@ constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2235,6 +3244,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun newAvalaraTaxConfiguration(): Optional<NewAvalaraTaxConfiguration> =
             Optional.ofNullable(newAvalaraTaxConfiguration)
 
@@ -2263,6 +3274,17 @@ constructor(
             }
         }
 
+        fun validate(): TaxConfiguration = apply {
+            if (!validated) {
+                if (newAvalaraTaxConfiguration == null && newTaxJarConfiguration == null) {
+                    throw OrbInvalidDataException("Unknown TaxConfiguration: $_json")
+                }
+                newAvalaraTaxConfiguration?.validate()
+                newTaxJarConfiguration?.validate()
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
@@ -2317,14 +3339,23 @@ constructor(
 
                 when (taxProvider) {
                     "avalara" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>())?.let {
-                            return TaxConfiguration(newAvalaraTaxConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(
+                                    newAvalaraTaxConfiguration = it,
+                                    _json = json
+                                )
+                            }
                     }
                     "taxjar" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>())?.let {
-                            return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
+                            }
                     }
                 }
 
@@ -2354,24 +3385,53 @@ constructor(
         class NewAvalaraTaxConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
-            @JsonProperty("tax_exemption_code") private val taxExemptionCode: String?,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
+            @JsonProperty("tax_exemption_code")
+            @ExcludeMissing
+            private val taxExemptionCode: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            fun taxExemptionCode(): Optional<String> =
+                Optional.ofNullable(taxExemptionCode.getNullable("tax_exemption_code"))
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
+
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonProperty("tax_exemption_code")
-            fun taxExemptionCode(): Optional<String> = Optional.ofNullable(taxExemptionCode)
+            @ExcludeMissing
+            fun _taxExemptionCode(): JsonField<String> = taxExemptionCode
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewAvalaraTaxConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    taxExemptionCode()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2381,9 +3441,9 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
-                private var taxExemptionCode: String? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
+                private var taxExemptionCode: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2395,17 +3455,26 @@ constructor(
                         newAvalaraTaxConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxExemptionCode(taxExemptionCode: String?) = apply {
-                    this.taxExemptionCode = taxExemptionCode
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
                 }
 
+                fun taxExemptionCode(taxExemptionCode: String?) =
+                    taxExemptionCode(JsonField.ofNullable(taxExemptionCode))
+
                 fun taxExemptionCode(taxExemptionCode: Optional<String>) =
                     taxExemptionCode(taxExemptionCode.orElse(null))
 
+                fun taxExemptionCode(taxExemptionCode: JsonField<String>) = apply {
+                    this.taxExemptionCode = taxExemptionCode
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -2510,20 +3579,42 @@ constructor(
         class NewTaxJarConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewTaxJarConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2533,8 +3624,8 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2545,9 +3636,15 @@ constructor(
                         newTaxJarConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
+
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -2759,23 +3856,44 @@ constructor(
     class TaxId
     @JsonCreator
     private constructor(
-        @JsonProperty("country") private val country: Country,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("value") private val value: String,
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<Country> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("country") fun country(): Country = country
+        fun country(): Country = country.getRequired("country")
+
+        fun type(): Type = type.getRequired("type")
+
+        fun value(): String = value.getRequired("value")
 
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("value") fun value(): String = value
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
+
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): TaxId = apply {
+            if (!validated) {
+                country()
+                type()
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2785,9 +3903,9 @@ constructor(
 
         class Builder {
 
-            private var country: Country? = null
-            private var type: Type? = null
-            private var value: String? = null
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2798,11 +3916,17 @@ constructor(
                 additionalProperties = taxId.additionalProperties.toMutableMap()
             }
 
-            fun country(country: Country) = apply { this.country = country }
+            fun country(country: Country) = country(JsonField.of(country))
+
+            fun country(country: JsonField<Country>) = apply { this.country = country }
+
+            fun type(type: Type) = type(JsonField.of(type))
+
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
-            fun type(type: Type) = apply { this.type = type }
+            fun value(value: String) = value(JsonField.of(value))
 
-            fun value(value: String) = apply { this.value = value }
+            fun value(value: JsonField<String>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateParams.kt
index f33b0e2f..28ed28bf 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/CustomerUpdateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,12 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint can be used to update the `payment_provider`, `payment_provider_id`, `name`,
+ * `email`, `email_delivery`, `tax_id`, `auto_collection`, `metadata`, `shipping_address`,
+ * `billing_address`, and `additional_emails` of an existing customer. Other fields on a customer
+ * are currently immutable.
+ */
 class CustomerUpdateParams
 constructor(
     private val customerId: String,
@@ -214,12 +221,187 @@ constructor(
      */
     fun taxId(): Optional<TaxId> = body.taxId()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+        body._accountingSyncConfiguration()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Additional email addresses for this customer. If populated, these email addresses will be
+     * CC'd for customer communications.
+     */
+    fun _additionalEmails(): JsonField<List<String>> = body._additionalEmails()
+
+    /**
+     * Used to determine if invoices for this customer will automatically attempt to charge a saved
+     * payment method, if available. This parameter defaults to `True` when a payment provider is
+     * provided on customer creation.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
+
+    fun _billingAddress(): JsonField<BillingAddress> = body._billingAddress()
+
+    /**
+     * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+     * creation time, will be set at subscription creation time.
+     */
+    fun _currency(): JsonField<String> = body._currency()
+
+    /** A valid customer email, to be used for invoicing and notifications. */
+    fun _email(): JsonField<String> = body._email()
+
+    fun _emailDelivery(): JsonField<Boolean> = body._emailDelivery()
+
+    /**
+     * The external customer ID. This can only be set if empty and the customer has no past or
+     * current subscriptions.
+     */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /** The full name of the customer */
+    fun _name(): JsonField<String> = body._name()
+
+    /**
+     * This is used for creating charges or invoices in an external system via Orb. When not in test
+     * mode:
+     * - the connection must first be configured in the Orb webapp.
+     * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+     *   `netsuite`), any product mappings must first be configured with the Orb team.
+     */
+    fun _paymentProvider(): JsonField<PaymentProvider> = body._paymentProvider()
+
+    /**
+     * The ID of this customer in an external payments solution, such as Stripe. This is used for
+     * creating charges or invoices in the external system via Orb.
+     */
+    fun _paymentProviderId(): JsonField<String> = body._paymentProviderId()
+
+    fun _reportingConfiguration(): JsonField<ReportingConfiguration> =
+        body._reportingConfiguration()
+
+    fun _shippingAddress(): JsonField<ShippingAddress> = body._shippingAddress()
+
+    fun _taxConfiguration(): JsonField<TaxConfiguration> = body._taxConfiguration()
+
+    /**
+     * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
+     * headers of invoices.
+     *
+     * ### Supported Tax ID Countries and Types
+     * |Country             |Type        |Description                                                                                            |
+     * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+     * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+     * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+     * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+     * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+     * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+     * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+     * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+     * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+     * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+     * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+     * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+     * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+     * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+     * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+     * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+     * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+     * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+     * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+     * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+     * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+     * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+     * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+     * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+     * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+     * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+     * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+     * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |France              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+     * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+     * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+     * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+     * |India               |`in_gst`    |Indian GST Number                                                                                      |
+     * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+     * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+     * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+     * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+     * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+     * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+     * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+     * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+     * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+     * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+     * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+     * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+     * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+     * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+     * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+     * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+     * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+     * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+     * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+     * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+     * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+     * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+     * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+     * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+     * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+     * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+     * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+     * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+     * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+     * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+     * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+     * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+     * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+     * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+     * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+     * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+     * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+     * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+     * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+     * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+     * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+     * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+     * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+     * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+     * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+     * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+     * |United States       |`us_ein`    |United States EIN                                                                                      |
+     * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+     * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+     * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+     */
+    fun _taxId(): JsonField<TaxId> = body._taxId()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): CustomerUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -238,37 +420,256 @@ constructor(
     @JsonCreator
     internal constructor(
         @JsonProperty("accounting_sync_configuration")
-        private val accountingSyncConfiguration: AccountingSyncConfiguration?,
-        @JsonProperty("additional_emails") private val additionalEmails: List<String>?,
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
-        @JsonProperty("billing_address") private val billingAddress: BillingAddress?,
-        @JsonProperty("currency") private val currency: String?,
-        @JsonProperty("email") private val email: String?,
-        @JsonProperty("email_delivery") private val emailDelivery: Boolean?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("name") private val name: String?,
-        @JsonProperty("payment_provider") private val paymentProvider: PaymentProvider?,
-        @JsonProperty("payment_provider_id") private val paymentProviderId: String?,
+        @ExcludeMissing
+        private val accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("additional_emails")
+        @ExcludeMissing
+        private val additionalEmails: JsonField<List<String>> = JsonMissing.of(),
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_address")
+        @ExcludeMissing
+        private val billingAddress: JsonField<BillingAddress> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("email")
+        @ExcludeMissing
+        private val email: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("email_delivery")
+        @ExcludeMissing
+        private val emailDelivery: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("payment_provider")
+        @ExcludeMissing
+        private val paymentProvider: JsonField<PaymentProvider> = JsonMissing.of(),
+        @JsonProperty("payment_provider_id")
+        @ExcludeMissing
+        private val paymentProviderId: JsonField<String> = JsonMissing.of(),
         @JsonProperty("reporting_configuration")
-        private val reportingConfiguration: ReportingConfiguration?,
-        @JsonProperty("shipping_address") private val shippingAddress: ShippingAddress?,
-        @JsonProperty("tax_configuration") private val taxConfiguration: TaxConfiguration?,
-        @JsonProperty("tax_id") private val taxId: TaxId?,
+        @ExcludeMissing
+        private val reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of(),
+        @JsonProperty("shipping_address")
+        @ExcludeMissing
+        private val shippingAddress: JsonField<ShippingAddress> = JsonMissing.of(),
+        @JsonProperty("tax_configuration")
+        @ExcludeMissing
+        private val taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of(),
+        @JsonProperty("tax_id")
+        @ExcludeMissing
+        private val taxId: JsonField<TaxId> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
+            Optional.ofNullable(
+                accountingSyncConfiguration.getNullable("accounting_sync_configuration")
+            )
+
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(): Optional<List<String>> =
+            Optional.ofNullable(additionalEmails.getNullable("additional_emails"))
+
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        fun billingAddress(): Optional<BillingAddress> =
+            Optional.ofNullable(billingAddress.getNullable("billing_address"))
+
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+        /** A valid customer email, to be used for invoicing and notifications. */
+        fun email(): Optional<String> = Optional.ofNullable(email.getNullable("email"))
+
+        fun emailDelivery(): Optional<Boolean> =
+            Optional.ofNullable(emailDelivery.getNullable("email_delivery"))
+
+        /**
+         * The external customer ID. This can only be set if empty and the customer has no past or
+         * current subscriptions.
+         */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The full name of the customer */
+        fun name(): Optional<String> = Optional.ofNullable(name.getNullable("name"))
+
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode:
+         * - the connection must first be configured in the Orb webapp.
+         * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+         *   `netsuite`), any product mappings must first be configured with the Orb team.
+         */
+        fun paymentProvider(): Optional<PaymentProvider> =
+            Optional.ofNullable(paymentProvider.getNullable("payment_provider"))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(): Optional<String> =
+            Optional.ofNullable(paymentProviderId.getNullable("payment_provider_id"))
+
+        fun reportingConfiguration(): Optional<ReportingConfiguration> =
+            Optional.ofNullable(reportingConfiguration.getNullable("reporting_configuration"))
+
+        fun shippingAddress(): Optional<ShippingAddress> =
+            Optional.ofNullable(shippingAddress.getNullable("shipping_address"))
+
+        fun taxConfiguration(): Optional<TaxConfiguration> =
+            Optional.ofNullable(taxConfiguration.getNullable("tax_configuration"))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId.getNullable("tax_id"))
+
         @JsonProperty("accounting_sync_configuration")
-        fun accountingSyncConfiguration(): Optional<AccountingSyncConfiguration> =
-            Optional.ofNullable(accountingSyncConfiguration)
+        @ExcludeMissing
+        fun _accountingSyncConfiguration(): JsonField<AccountingSyncConfiguration> =
+            accountingSyncConfiguration
 
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
          */
         @JsonProperty("additional_emails")
-        fun additionalEmails(): Optional<List<String>> = Optional.ofNullable(additionalEmails)
+        @ExcludeMissing
+        fun _additionalEmails(): JsonField<List<String>> = additionalEmails
 
         /**
          * Used to determine if invoices for this customer will automatically attempt to charge a
@@ -276,39 +677,43 @@ constructor(
          * provider is provided on customer creation.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         @JsonProperty("billing_address")
-        fun billingAddress(): Optional<BillingAddress> = Optional.ofNullable(billingAddress)
+        @ExcludeMissing
+        fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
          */
-        @JsonProperty("currency") fun currency(): Optional<String> = Optional.ofNullable(currency)
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** A valid customer email, to be used for invoicing and notifications. */
-        @JsonProperty("email") fun email(): Optional<String> = Optional.ofNullable(email)
+        @JsonProperty("email") @ExcludeMissing fun _email(): JsonField<String> = email
 
         @JsonProperty("email_delivery")
-        fun emailDelivery(): Optional<Boolean> = Optional.ofNullable(emailDelivery)
+        @ExcludeMissing
+        fun _emailDelivery(): JsonField<Boolean> = emailDelivery
 
         /**
          * The external customer ID. This can only be set if empty and the customer has no past or
          * current subscriptions.
          */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /** The full name of the customer */
-        @JsonProperty("name") fun name(): Optional<String> = Optional.ofNullable(name)
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
@@ -318,24 +723,28 @@ constructor(
          *   `netsuite`), any product mappings must first be configured with the Orb team.
          */
         @JsonProperty("payment_provider")
-        fun paymentProvider(): Optional<PaymentProvider> = Optional.ofNullable(paymentProvider)
+        @ExcludeMissing
+        fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
         @JsonProperty("payment_provider_id")
-        fun paymentProviderId(): Optional<String> = Optional.ofNullable(paymentProviderId)
+        @ExcludeMissing
+        fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
         @JsonProperty("reporting_configuration")
-        fun reportingConfiguration(): Optional<ReportingConfiguration> =
-            Optional.ofNullable(reportingConfiguration)
+        @ExcludeMissing
+        fun _reportingConfiguration(): JsonField<ReportingConfiguration> = reportingConfiguration
 
         @JsonProperty("shipping_address")
-        fun shippingAddress(): Optional<ShippingAddress> = Optional.ofNullable(shippingAddress)
+        @ExcludeMissing
+        fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
         @JsonProperty("tax_configuration")
-        fun taxConfiguration(): Optional<TaxConfiguration> = Optional.ofNullable(taxConfiguration)
+        @ExcludeMissing
+        fun _taxConfiguration(): JsonField<TaxConfiguration> = taxConfiguration
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -443,12 +852,36 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        @JsonProperty("tax_id") fun taxId(): Optional<TaxId> = Optional.ofNullable(taxId)
+        @JsonProperty("tax_id") @ExcludeMissing fun _taxId(): JsonField<TaxId> = taxId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): CustomerUpdateBody = apply {
+            if (!validated) {
+                accountingSyncConfiguration().map { it.validate() }
+                additionalEmails()
+                autoCollection()
+                billingAddress().map { it.validate() }
+                currency()
+                email()
+                emailDelivery()
+                externalCustomerId()
+                metadata().map { it.validate() }
+                name()
+                paymentProvider()
+                paymentProviderId()
+                reportingConfiguration().map { it.validate() }
+                shippingAddress().map { it.validate() }
+                taxConfiguration()
+                taxId().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -458,28 +891,29 @@ constructor(
 
         class Builder {
 
-            private var accountingSyncConfiguration: AccountingSyncConfiguration? = null
-            private var additionalEmails: MutableList<String>? = null
-            private var autoCollection: Boolean? = null
-            private var billingAddress: BillingAddress? = null
-            private var currency: String? = null
-            private var email: String? = null
-            private var emailDelivery: Boolean? = null
-            private var externalCustomerId: String? = null
-            private var metadata: Metadata? = null
-            private var name: String? = null
-            private var paymentProvider: PaymentProvider? = null
-            private var paymentProviderId: String? = null
-            private var reportingConfiguration: ReportingConfiguration? = null
-            private var shippingAddress: ShippingAddress? = null
-            private var taxConfiguration: TaxConfiguration? = null
-            private var taxId: TaxId? = null
+            private var accountingSyncConfiguration: JsonField<AccountingSyncConfiguration> =
+                JsonMissing.of()
+            private var additionalEmails: JsonField<MutableList<String>>? = null
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
+            private var currency: JsonField<String> = JsonMissing.of()
+            private var email: JsonField<String> = JsonMissing.of()
+            private var emailDelivery: JsonField<Boolean> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var name: JsonField<String> = JsonMissing.of()
+            private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
+            private var paymentProviderId: JsonField<String> = JsonMissing.of()
+            private var reportingConfiguration: JsonField<ReportingConfiguration> = JsonMissing.of()
+            private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
+            private var taxConfiguration: JsonField<TaxConfiguration> = JsonMissing.of()
+            private var taxId: JsonField<TaxId> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(customerUpdateBody: CustomerUpdateBody) = apply {
                 accountingSyncConfiguration = customerUpdateBody.accountingSyncConfiguration
-                additionalEmails = customerUpdateBody.additionalEmails?.toMutableList()
+                additionalEmails = customerUpdateBody.additionalEmails.map { it.toMutableList() }
                 autoCollection = customerUpdateBody.autoCollection
                 billingAddress = customerUpdateBody.billingAddress
                 currency = customerUpdateBody.currency
@@ -499,19 +933,22 @@ constructor(
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: AccountingSyncConfiguration?
-            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+            ) = accountingSyncConfiguration(JsonField.ofNullable(accountingSyncConfiguration))
 
             fun accountingSyncConfiguration(
                 accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
             ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+            fun accountingSyncConfiguration(
+                accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+            ) = apply { this.accountingSyncConfiguration = accountingSyncConfiguration }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
-            fun additionalEmails(additionalEmails: List<String>?) = apply {
-                this.additionalEmails = additionalEmails?.toMutableList()
-            }
+            fun additionalEmails(additionalEmails: List<String>?) =
+                additionalEmails(JsonField.ofNullable(additionalEmails))
 
             /**
              * Additional email addresses for this customer. If populated, these email addresses
@@ -520,13 +957,29 @@ constructor(
             fun additionalEmails(additionalEmails: Optional<List<String>>) =
                 additionalEmails(additionalEmails.orElse(null))
 
+            /**
+             * Additional email addresses for this customer. If populated, these email addresses
+             * will be CC'd for customer communications.
+             */
+            fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+                this.additionalEmails = additionalEmails.map { it.toMutableList() }
+            }
+
             /**
              * Additional email addresses for this customer. If populated, these email addresses
              * will be CC'd for customer communications.
              */
             fun addAdditionalEmail(additionalEmail: String) = apply {
                 additionalEmails =
-                    (additionalEmails ?: mutableListOf()).apply { add(additionalEmail) }
+                    (additionalEmails ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(additionalEmail)
+                    }
             }
 
             /**
@@ -534,9 +987,8 @@ constructor(
              * a saved payment method, if available. This parameter defaults to `True` when a
              * payment provider is provided on customer creation.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Used to determine if invoices for this customer will automatically attempt to charge
@@ -554,18 +1006,30 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
-            fun billingAddress(billingAddress: BillingAddress?) = apply {
-                this.billingAddress = billingAddress
+            /**
+             * Used to determine if invoices for this customer will automatically attempt to charge
+             * a saved payment method, if available. This parameter defaults to `True` when a
+             * payment provider is provided on customer creation.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
             }
 
+            fun billingAddress(billingAddress: BillingAddress?) =
+                billingAddress(JsonField.ofNullable(billingAddress))
+
             fun billingAddress(billingAddress: Optional<BillingAddress>) =
                 billingAddress(billingAddress.orElse(null))
 
+            fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+                this.billingAddress = billingAddress
+            }
+
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
              * at creation time, will be set at subscription creation time.
              */
-            fun currency(currency: String?) = apply { this.currency = currency }
+            fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
             /**
              * An ISO 4217 currency string used for the customer's invoices and balance. If not set
@@ -573,15 +1037,23 @@ constructor(
              */
             fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+            /**
+             * An ISO 4217 currency string used for the customer's invoices and balance. If not set
+             * at creation time, will be set at subscription creation time.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
             /** A valid customer email, to be used for invoicing and notifications. */
-            fun email(email: String?) = apply { this.email = email }
+            fun email(email: String?) = email(JsonField.ofNullable(email))
 
             /** A valid customer email, to be used for invoicing and notifications. */
             fun email(email: Optional<String>) = email(email.orElse(null))
 
-            fun emailDelivery(emailDelivery: Boolean?) = apply {
-                this.emailDelivery = emailDelivery
-            }
+            /** A valid customer email, to be used for invoicing and notifications. */
+            fun email(email: JsonField<String>) = apply { this.email = email }
+
+            fun emailDelivery(emailDelivery: Boolean?) =
+                emailDelivery(JsonField.ofNullable(emailDelivery))
 
             fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
 
@@ -589,13 +1061,16 @@ constructor(
             fun emailDelivery(emailDelivery: Optional<Boolean>) =
                 emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+            fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+                this.emailDelivery = emailDelivery
+            }
+
             /**
              * The external customer ID. This can only be set if empty and the customer has no past
              * or current subscriptions.
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * The external customer ID. This can only be set if empty and the customer has no past
@@ -604,12 +1079,20 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * The external customer ID. This can only be set if empty and the customer has no past
+             * or current subscriptions.
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -618,12 +1101,22 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /** The full name of the customer */
-            fun name(name: String?) = apply { this.name = name }
+            fun name(name: String?) = name(JsonField.ofNullable(name))
 
             /** The full name of the customer */
             fun name(name: Optional<String>) = name(name.orElse(null))
 
+            /** The full name of the customer */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
              * in test mode:
@@ -632,9 +1125,8 @@ constructor(
              *   `bill.com`, `netsuite`), any product mappings must first be configured with the Orb
              *   team.
              */
-            fun paymentProvider(paymentProvider: PaymentProvider?) = apply {
-                this.paymentProvider = paymentProvider
-            }
+            fun paymentProvider(paymentProvider: PaymentProvider?) =
+                paymentProvider(JsonField.ofNullable(paymentProvider))
 
             /**
              * This is used for creating charges or invoices in an external system via Orb. When not
@@ -647,54 +1139,188 @@ constructor(
             fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
                 paymentProvider(paymentProvider.orElse(null))
 
+            /**
+             * This is used for creating charges or invoices in an external system via Orb. When not
+             * in test mode:
+             * - the connection must first be configured in the Orb webapp.
+             * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`,
+             *   `bill.com`, `netsuite`), any product mappings must first be configured with the Orb
+             *   team.
+             */
+            fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+                this.paymentProvider = paymentProvider
+            }
+
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: String?) = apply {
-                this.paymentProviderId = paymentProviderId
-            }
+            fun paymentProviderId(paymentProviderId: String?) =
+                paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+            /**
+             * The ID of this customer in an external payments solution, such as Stripe. This is
+             * used for creating charges or invoices in the external system via Orb.
+             */
+            fun paymentProviderId(paymentProviderId: Optional<String>) =
+                paymentProviderId(paymentProviderId.orElse(null))
 
             /**
              * The ID of this customer in an external payments solution, such as Stripe. This is
              * used for creating charges or invoices in the external system via Orb.
              */
-            fun paymentProviderId(paymentProviderId: Optional<String>) =
-                paymentProviderId(paymentProviderId.orElse(null))
-
-            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-                this.reportingConfiguration = reportingConfiguration
-            }
-
-            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-                reportingConfiguration(reportingConfiguration.orElse(null))
-
-            fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-                this.shippingAddress = shippingAddress
-            }
-
-            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-                shippingAddress(shippingAddress.orElse(null))
-
-            fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-                this.taxConfiguration = taxConfiguration
-            }
-
-            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-                taxConfiguration(taxConfiguration.orElse(null))
-
-            fun taxConfiguration(
-                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-            ) = apply {
-                this.taxConfiguration =
-                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
-            }
-
-            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-                apply {
-                    this.taxConfiguration =
-                        TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration)
-                }
+            fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+                this.paymentProviderId = paymentProviderId
+            }
+
+            fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) =
+                reportingConfiguration(JsonField.ofNullable(reportingConfiguration))
+
+            fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+                reportingConfiguration(reportingConfiguration.orElse(null))
+
+            fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+                apply {
+                    this.reportingConfiguration = reportingConfiguration
+                }
+
+            fun shippingAddress(shippingAddress: ShippingAddress?) =
+                shippingAddress(JsonField.ofNullable(shippingAddress))
+
+            fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+                shippingAddress(shippingAddress.orElse(null))
+
+            fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+                this.shippingAddress = shippingAddress
+            }
+
+            fun taxConfiguration(taxConfiguration: TaxConfiguration?) =
+                taxConfiguration(JsonField.ofNullable(taxConfiguration))
+
+            fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+                taxConfiguration(taxConfiguration.orElse(null))
+
+            fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+                this.taxConfiguration = taxConfiguration
+            }
+
+            fun taxConfiguration(
+                newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+            ) =
+                taxConfiguration(
+                    TaxConfiguration.ofNewAvalaraTaxConfiguration(newAvalaraTaxConfiguration)
+                )
+
+            fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+                taxConfiguration(TaxConfiguration.ofNewTaxJarConfiguration(newTaxJarConfiguration))
+
+            /**
+             * Tax IDs are commonly required to be displayed on customer invoices, which are added
+             * to the headers of invoices.
+             *
+             * ### Supported Tax ID Countries and Types
+             * |Country             |Type        |Description                                                                                            |
+             * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+             * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+             * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+             * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+             * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+             * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+             * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+             * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+             * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+             * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+             * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+             * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+             * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+             * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+             * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+             * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+             * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+             * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+             * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+             * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+             * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+             * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+             * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+             * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+             * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+             * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+             * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+             * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |France              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+             * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+             * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+             * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+             * |India               |`in_gst`    |Indian GST Number                                                                                      |
+             * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+             * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+             * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+             * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+             * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+             * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+             * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+             * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+             * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+             * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+             * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+             * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+             * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+             * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+             * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+             * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+             * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+             * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+             * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+             * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+             * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+             * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+             * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+             * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+             * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+             * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+             * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+             * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+             * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+             * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+             * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+             * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+             * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+             * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+             * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+             * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+             * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+             * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+             * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+             * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+             * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+             * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+             * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+             * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+             * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+             * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+             * |United States       |`us_ein`    |United States EIN                                                                                      |
+             * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+             * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+             * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+             */
+            fun taxId(taxId: TaxId?) = taxId(JsonField.ofNullable(taxId))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -802,7 +1428,7 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: TaxId?) = apply { this.taxId = taxId }
+            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
             /**
              * Tax IDs are commonly required to be displayed on customer invoices, which are added
@@ -910,7 +1536,7 @@ constructor(
              * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
              * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
              */
-            fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+            fun taxId(taxId: JsonField<TaxId>) = apply { this.taxId = taxId }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -934,7 +1560,7 @@ constructor(
             fun build(): CustomerUpdateBody =
                 CustomerUpdateBody(
                     accountingSyncConfiguration,
-                    additionalEmails?.toImmutable(),
+                    (additionalEmails ?: JsonMissing.of()).map { it.toImmutable() },
                     autoCollection,
                     billingAddress,
                     currency,
@@ -1005,6 +1631,10 @@ constructor(
             accountingSyncConfiguration: Optional<AccountingSyncConfiguration>
         ) = accountingSyncConfiguration(accountingSyncConfiguration.orElse(null))
 
+        fun accountingSyncConfiguration(
+            accountingSyncConfiguration: JsonField<AccountingSyncConfiguration>
+        ) = apply { body.accountingSyncConfiguration(accountingSyncConfiguration) }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1020,6 +1650,14 @@ constructor(
         fun additionalEmails(additionalEmails: Optional<List<String>>) =
             additionalEmails(additionalEmails.orElse(null))
 
+        /**
+         * Additional email addresses for this customer. If populated, these email addresses will be
+         * CC'd for customer communications.
+         */
+        fun additionalEmails(additionalEmails: JsonField<List<String>>) = apply {
+            body.additionalEmails(additionalEmails)
+        }
+
         /**
          * Additional email addresses for this customer. If populated, these email addresses will be
          * CC'd for customer communications.
@@ -1051,6 +1689,15 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Used to determine if invoices for this customer will automatically attempt to charge a
+         * saved payment method, if available. This parameter defaults to `True` when a payment
+         * provider is provided on customer creation.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         fun billingAddress(billingAddress: BillingAddress?) = apply {
             body.billingAddress(billingAddress)
         }
@@ -1058,6 +1705,10 @@ constructor(
         fun billingAddress(billingAddress: Optional<BillingAddress>) =
             billingAddress(billingAddress.orElse(null))
 
+        fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
+            body.billingAddress(billingAddress)
+        }
+
         /**
          * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
          * creation time, will be set at subscription creation time.
@@ -1070,12 +1721,21 @@ constructor(
          */
         fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+        /**
+         * An ISO 4217 currency string used for the customer's invoices and balance. If not set at
+         * creation time, will be set at subscription creation time.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /** A valid customer email, to be used for invoicing and notifications. */
         fun email(email: String?) = apply { body.email(email) }
 
         /** A valid customer email, to be used for invoicing and notifications. */
         fun email(email: Optional<String>) = email(email.orElse(null))
 
+        /** A valid customer email, to be used for invoicing and notifications. */
+        fun email(email: JsonField<String>) = apply { body.email(email) }
+
         fun emailDelivery(emailDelivery: Boolean?) = apply { body.emailDelivery(emailDelivery) }
 
         fun emailDelivery(emailDelivery: Boolean) = emailDelivery(emailDelivery as Boolean?)
@@ -1084,6 +1744,10 @@ constructor(
         fun emailDelivery(emailDelivery: Optional<Boolean>) =
             emailDelivery(emailDelivery.orElse(null) as Boolean?)
 
+        fun emailDelivery(emailDelivery: JsonField<Boolean>) = apply {
+            body.emailDelivery(emailDelivery)
+        }
+
         /**
          * The external customer ID. This can only be set if empty and the customer has no past or
          * current subscriptions.
@@ -1099,6 +1763,14 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /**
+         * The external customer ID. This can only be set if empty and the customer has no past or
+         * current subscriptions.
+         */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -1113,12 +1785,22 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /** The full name of the customer */
         fun name(name: String?) = apply { body.name(name) }
 
         /** The full name of the customer */
         fun name(name: Optional<String>) = name(name.orElse(null))
 
+        /** The full name of the customer */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         /**
          * This is used for creating charges or invoices in an external system via Orb. When not in
          * test mode:
@@ -1140,6 +1822,17 @@ constructor(
         fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
             paymentProvider(paymentProvider.orElse(null))
 
+        /**
+         * This is used for creating charges or invoices in an external system via Orb. When not in
+         * test mode:
+         * - the connection must first be configured in the Orb webapp.
+         * - if the provider is an invoicing provider (`stripe_invoice`, `quickbooks`, `bill.com`,
+         *   `netsuite`), any product mappings must first be configured with the Orb team.
+         */
+        fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
+            body.paymentProvider(paymentProvider)
+        }
+
         /**
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
@@ -1152,38 +1845,167 @@ constructor(
          * The ID of this customer in an external payments solution, such as Stripe. This is used
          * for creating charges or invoices in the external system via Orb.
          */
-        fun paymentProviderId(paymentProviderId: Optional<String>) =
-            paymentProviderId(paymentProviderId.orElse(null))
-
-        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
-            body.reportingConfiguration(reportingConfiguration)
-        }
-
-        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
-            reportingConfiguration(reportingConfiguration.orElse(null))
-
-        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
-            body.shippingAddress(shippingAddress)
-        }
-
-        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
-            shippingAddress(shippingAddress.orElse(null))
-
-        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
-            body.taxConfiguration(taxConfiguration)
-        }
-
-        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
-            taxConfiguration(taxConfiguration.orElse(null))
-
-        fun taxConfiguration(
-            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
-        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
-
-        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
-            apply {
-                body.taxConfiguration(newTaxJarConfiguration)
-            }
+        fun paymentProviderId(paymentProviderId: Optional<String>) =
+            paymentProviderId(paymentProviderId.orElse(null))
+
+        /**
+         * The ID of this customer in an external payments solution, such as Stripe. This is used
+         * for creating charges or invoices in the external system via Orb.
+         */
+        fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
+            body.paymentProviderId(paymentProviderId)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: ReportingConfiguration?) = apply {
+            body.reportingConfiguration(reportingConfiguration)
+        }
+
+        fun reportingConfiguration(reportingConfiguration: Optional<ReportingConfiguration>) =
+            reportingConfiguration(reportingConfiguration.orElse(null))
+
+        fun reportingConfiguration(reportingConfiguration: JsonField<ReportingConfiguration>) =
+            apply {
+                body.reportingConfiguration(reportingConfiguration)
+            }
+
+        fun shippingAddress(shippingAddress: ShippingAddress?) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
+
+        fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
+            body.shippingAddress(shippingAddress)
+        }
+
+        fun taxConfiguration(taxConfiguration: TaxConfiguration?) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(taxConfiguration: Optional<TaxConfiguration>) =
+            taxConfiguration(taxConfiguration.orElse(null))
+
+        fun taxConfiguration(taxConfiguration: JsonField<TaxConfiguration>) = apply {
+            body.taxConfiguration(taxConfiguration)
+        }
+
+        fun taxConfiguration(
+            newAvalaraTaxConfiguration: TaxConfiguration.NewAvalaraTaxConfiguration
+        ) = apply { body.taxConfiguration(newAvalaraTaxConfiguration) }
+
+        fun taxConfiguration(newTaxJarConfiguration: TaxConfiguration.NewTaxJarConfiguration) =
+            apply {
+                body.taxConfiguration(newTaxJarConfiguration)
+            }
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1291,7 +2113,7 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: TaxId?) = apply { body.taxId(taxId) }
+        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1399,7 +2221,26 @@ constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun taxId(taxId: Optional<TaxId>) = taxId(taxId.orElse(null))
+        fun taxId(taxId: JsonField<TaxId>) = apply { body.taxId(taxId) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -1499,25 +2340,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): CustomerUpdateParams =
             CustomerUpdateParams(
                 checkNotNull(customerId) { "`customerId` is required but was not set" },
@@ -1532,22 +2354,40 @@ constructor(
     @JsonCreator
     private constructor(
         @JsonProperty("accounting_providers")
-        private val accountingProviders: List<AccountingProvider>?,
-        @JsonProperty("excluded") private val excluded: Boolean?,
+        @ExcludeMissing
+        private val accountingProviders: JsonField<List<AccountingProvider>> = JsonMissing.of(),
+        @JsonProperty("excluded")
+        @ExcludeMissing
+        private val excluded: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("accounting_providers")
         fun accountingProviders(): Optional<List<AccountingProvider>> =
-            Optional.ofNullable(accountingProviders)
+            Optional.ofNullable(accountingProviders.getNullable("accounting_providers"))
+
+        fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded.getNullable("excluded"))
+
+        @JsonProperty("accounting_providers")
+        @ExcludeMissing
+        fun _accountingProviders(): JsonField<List<AccountingProvider>> = accountingProviders
 
-        @JsonProperty("excluded") fun excluded(): Optional<Boolean> = Optional.ofNullable(excluded)
+        @JsonProperty("excluded") @ExcludeMissing fun _excluded(): JsonField<Boolean> = excluded
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AccountingSyncConfiguration = apply {
+            if (!validated) {
+                accountingProviders().map { it.forEach { it.validate() } }
+                excluded()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1557,38 +2397,52 @@ constructor(
 
         class Builder {
 
-            private var accountingProviders: MutableList<AccountingProvider>? = null
-            private var excluded: Boolean? = null
+            private var accountingProviders: JsonField<MutableList<AccountingProvider>>? = null
+            private var excluded: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(accountingSyncConfiguration: AccountingSyncConfiguration) = apply {
                 accountingProviders =
-                    accountingSyncConfiguration.accountingProviders?.toMutableList()
+                    accountingSyncConfiguration.accountingProviders.map { it.toMutableList() }
                 excluded = accountingSyncConfiguration.excluded
                 additionalProperties =
                     accountingSyncConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun accountingProviders(accountingProviders: List<AccountingProvider>?) = apply {
-                this.accountingProviders = accountingProviders?.toMutableList()
-            }
+            fun accountingProviders(accountingProviders: List<AccountingProvider>?) =
+                accountingProviders(JsonField.ofNullable(accountingProviders))
 
             fun accountingProviders(accountingProviders: Optional<List<AccountingProvider>>) =
                 accountingProviders(accountingProviders.orElse(null))
 
+            fun accountingProviders(accountingProviders: JsonField<List<AccountingProvider>>) =
+                apply {
+                    this.accountingProviders = accountingProviders.map { it.toMutableList() }
+                }
+
             fun addAccountingProvider(accountingProvider: AccountingProvider) = apply {
                 accountingProviders =
-                    (accountingProviders ?: mutableListOf()).apply { add(accountingProvider) }
+                    (accountingProviders ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(accountingProvider)
+                    }
             }
 
-            fun excluded(excluded: Boolean?) = apply { this.excluded = excluded }
+            fun excluded(excluded: Boolean?) = excluded(JsonField.ofNullable(excluded))
 
             fun excluded(excluded: Boolean) = excluded(excluded as Boolean?)
 
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun excluded(excluded: Optional<Boolean>) = excluded(excluded.orElse(null) as Boolean?)
 
+            fun excluded(excluded: JsonField<Boolean>) = apply { this.excluded = excluded }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1610,7 +2464,7 @@ constructor(
 
             fun build(): AccountingSyncConfiguration =
                 AccountingSyncConfiguration(
-                    accountingProviders?.toImmutable(),
+                    (accountingProviders ?: JsonMissing.of()).map { it.toImmutable() },
                     excluded,
                     additionalProperties.toImmutable(),
                 )
@@ -1620,21 +2474,43 @@ constructor(
         class AccountingProvider
         @JsonCreator
         private constructor(
-            @JsonProperty("external_provider_id") private val externalProviderId: String,
-            @JsonProperty("provider_type") private val providerType: String,
+            @JsonProperty("external_provider_id")
+            @ExcludeMissing
+            private val externalProviderId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            private val providerType: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
+            fun externalProviderId(): String =
+                externalProviderId.getRequired("external_provider_id")
+
+            fun providerType(): String = providerType.getRequired("provider_type")
+
             @JsonProperty("external_provider_id")
-            fun externalProviderId(): String = externalProviderId
+            @ExcludeMissing
+            fun _externalProviderId(): JsonField<String> = externalProviderId
 
-            @JsonProperty("provider_type") fun providerType(): String = providerType
+            @JsonProperty("provider_type")
+            @ExcludeMissing
+            fun _providerType(): JsonField<String> = providerType
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): AccountingProvider = apply {
+                if (!validated) {
+                    externalProviderId()
+                    providerType()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1644,8 +2520,8 @@ constructor(
 
             class Builder {
 
-                private var externalProviderId: String? = null
-                private var providerType: String? = null
+                private var externalProviderId: JsonField<String>? = null
+                private var providerType: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1655,11 +2531,18 @@ constructor(
                     additionalProperties = accountingProvider.additionalProperties.toMutableMap()
                 }
 
-                fun externalProviderId(externalProviderId: String) = apply {
+                fun externalProviderId(externalProviderId: String) =
+                    externalProviderId(JsonField.of(externalProviderId))
+
+                fun externalProviderId(externalProviderId: JsonField<String>) = apply {
                     this.externalProviderId = externalProviderId
                 }
 
-                fun providerType(providerType: String) = apply { this.providerType = providerType }
+                fun providerType(providerType: String) = providerType(JsonField.of(providerType))
+
+                fun providerType(providerType: JsonField<String>) = apply {
+                    this.providerType = providerType
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1733,33 +2616,73 @@ constructor(
     class BillingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
+
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
+
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): BillingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1769,12 +2692,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1788,30 +2711,42 @@ constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1878,6 +2813,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2012,17 +2955,30 @@ constructor(
     class ReportingConfiguration
     @JsonCreator
     private constructor(
-        @JsonProperty("exempt") private val exempt: Boolean,
+        @JsonProperty("exempt")
+        @ExcludeMissing
+        private val exempt: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("exempt") fun exempt(): Boolean = exempt
+        fun exempt(): Boolean = exempt.getRequired("exempt")
+
+        @JsonProperty("exempt") @ExcludeMissing fun _exempt(): JsonField<Boolean> = exempt
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReportingConfiguration = apply {
+            if (!validated) {
+                exempt()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2032,7 +2988,7 @@ constructor(
 
         class Builder {
 
-            private var exempt: Boolean? = null
+            private var exempt: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2041,7 +2997,9 @@ constructor(
                 additionalProperties = reportingConfiguration.additionalProperties.toMutableMap()
             }
 
-            fun exempt(exempt: Boolean) = apply { this.exempt = exempt }
+            fun exempt(exempt: Boolean) = exempt(JsonField.of(exempt))
+
+            fun exempt(exempt: JsonField<Boolean>) = apply { this.exempt = exempt }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -2091,33 +3049,73 @@ constructor(
     class ShippingAddress
     @JsonCreator
     private constructor(
-        @JsonProperty("city") private val city: String?,
-        @JsonProperty("country") private val country: String?,
-        @JsonProperty("line1") private val line1: String?,
-        @JsonProperty("line2") private val line2: String?,
-        @JsonProperty("postal_code") private val postalCode: String?,
-        @JsonProperty("state") private val state: String?,
+        @JsonProperty("city")
+        @ExcludeMissing
+        private val city: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line1")
+        @ExcludeMissing
+        private val line1: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("line2")
+        @ExcludeMissing
+        private val line2: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        private val postalCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("state")
+        @ExcludeMissing
+        private val state: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("city") fun city(): Optional<String> = Optional.ofNullable(city)
+        fun city(): Optional<String> = Optional.ofNullable(city.getNullable("city"))
+
+        fun country(): Optional<String> = Optional.ofNullable(country.getNullable("country"))
+
+        fun line1(): Optional<String> = Optional.ofNullable(line1.getNullable("line1"))
 
-        @JsonProperty("country") fun country(): Optional<String> = Optional.ofNullable(country)
+        fun line2(): Optional<String> = Optional.ofNullable(line2.getNullable("line2"))
 
-        @JsonProperty("line1") fun line1(): Optional<String> = Optional.ofNullable(line1)
+        fun postalCode(): Optional<String> =
+            Optional.ofNullable(postalCode.getNullable("postal_code"))
 
-        @JsonProperty("line2") fun line2(): Optional<String> = Optional.ofNullable(line2)
+        fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
+
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
+
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
+
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
+
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
         @JsonProperty("postal_code")
-        fun postalCode(): Optional<String> = Optional.ofNullable(postalCode)
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") fun state(): Optional<String> = Optional.ofNullable(state)
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ShippingAddress = apply {
+            if (!validated) {
+                city()
+                country()
+                line1()
+                line2()
+                postalCode()
+                state()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2127,12 +3125,12 @@ constructor(
 
         class Builder {
 
-            private var city: String? = null
-            private var country: String? = null
-            private var line1: String? = null
-            private var line2: String? = null
-            private var postalCode: String? = null
-            private var state: String? = null
+            private var city: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<String> = JsonMissing.of()
+            private var line1: JsonField<String> = JsonMissing.of()
+            private var line2: JsonField<String> = JsonMissing.of()
+            private var postalCode: JsonField<String> = JsonMissing.of()
+            private var state: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2146,30 +3144,42 @@ constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String?) = apply { this.city = city }
+            fun city(city: String?) = city(JsonField.ofNullable(city))
 
             fun city(city: Optional<String>) = city(city.orElse(null))
 
-            fun country(country: String?) = apply { this.country = country }
+            fun city(city: JsonField<String>) = apply { this.city = city }
+
+            fun country(country: String?) = country(JsonField.ofNullable(country))
 
             fun country(country: Optional<String>) = country(country.orElse(null))
 
-            fun line1(line1: String?) = apply { this.line1 = line1 }
+            fun country(country: JsonField<String>) = apply { this.country = country }
+
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
 
             fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
-            fun line2(line2: String?) = apply { this.line2 = line2 }
+            fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
+
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
 
             fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
-            fun postalCode(postalCode: String?) = apply { this.postalCode = postalCode }
+            fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
+
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
 
             fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
-            fun state(state: String?) = apply { this.state = state }
+            fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
+
+            fun state(state: String?) = state(JsonField.ofNullable(state))
 
             fun state(state: Optional<String>) = state(state.orElse(null))
 
+            fun state(state: JsonField<String>) = apply { this.state = state }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2228,6 +3238,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun newAvalaraTaxConfiguration(): Optional<NewAvalaraTaxConfiguration> =
             Optional.ofNullable(newAvalaraTaxConfiguration)
 
@@ -2256,6 +3268,17 @@ constructor(
             }
         }
 
+        fun validate(): TaxConfiguration = apply {
+            if (!validated) {
+                if (newAvalaraTaxConfiguration == null && newTaxJarConfiguration == null) {
+                    throw OrbInvalidDataException("Unknown TaxConfiguration: $_json")
+                }
+                newAvalaraTaxConfiguration?.validate()
+                newTaxJarConfiguration?.validate()
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
@@ -2310,14 +3333,23 @@ constructor(
 
                 when (taxProvider) {
                     "avalara" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>())?.let {
-                            return TaxConfiguration(newAvalaraTaxConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewAvalaraTaxConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(
+                                    newAvalaraTaxConfiguration = it,
+                                    _json = json
+                                )
+                            }
                     }
                     "taxjar" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>())?.let {
-                            return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewTaxJarConfiguration>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return TaxConfiguration(newTaxJarConfiguration = it, _json = json)
+                            }
                     }
                 }
 
@@ -2347,24 +3379,53 @@ constructor(
         class NewAvalaraTaxConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
-            @JsonProperty("tax_exemption_code") private val taxExemptionCode: String?,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
+            @JsonProperty("tax_exemption_code")
+            @ExcludeMissing
+            private val taxExemptionCode: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            fun taxExemptionCode(): Optional<String> =
+                Optional.ofNullable(taxExemptionCode.getNullable("tax_exemption_code"))
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
+
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonProperty("tax_exemption_code")
-            fun taxExemptionCode(): Optional<String> = Optional.ofNullable(taxExemptionCode)
+            @ExcludeMissing
+            fun _taxExemptionCode(): JsonField<String> = taxExemptionCode
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewAvalaraTaxConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    taxExemptionCode()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2374,9 +3435,9 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
-                private var taxExemptionCode: String? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
+                private var taxExemptionCode: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2388,17 +3449,26 @@ constructor(
                         newAvalaraTaxConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxExemptionCode(taxExemptionCode: String?) = apply {
-                    this.taxExemptionCode = taxExemptionCode
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
                 }
 
+                fun taxExemptionCode(taxExemptionCode: String?) =
+                    taxExemptionCode(JsonField.ofNullable(taxExemptionCode))
+
                 fun taxExemptionCode(taxExemptionCode: Optional<String>) =
                     taxExemptionCode(taxExemptionCode.orElse(null))
 
+                fun taxExemptionCode(taxExemptionCode: JsonField<String>) = apply {
+                    this.taxExemptionCode = taxExemptionCode
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -2503,20 +3573,42 @@ constructor(
         class NewTaxJarConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("tax_exempt") private val taxExempt: Boolean,
-            @JsonProperty("tax_provider") private val taxProvider: TaxProvider,
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            private val taxExempt: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            private val taxProvider: JsonField<TaxProvider> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("tax_exempt") fun taxExempt(): Boolean = taxExempt
+            fun taxExempt(): Boolean = taxExempt.getRequired("tax_exempt")
+
+            fun taxProvider(): TaxProvider = taxProvider.getRequired("tax_provider")
+
+            @JsonProperty("tax_exempt")
+            @ExcludeMissing
+            fun _taxExempt(): JsonField<Boolean> = taxExempt
 
-            @JsonProperty("tax_provider") fun taxProvider(): TaxProvider = taxProvider
+            @JsonProperty("tax_provider")
+            @ExcludeMissing
+            fun _taxProvider(): JsonField<TaxProvider> = taxProvider
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewTaxJarConfiguration = apply {
+                if (!validated) {
+                    taxExempt()
+                    taxProvider()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2526,8 +3618,8 @@ constructor(
 
             class Builder {
 
-                private var taxExempt: Boolean? = null
-                private var taxProvider: TaxProvider? = null
+                private var taxExempt: JsonField<Boolean>? = null
+                private var taxProvider: JsonField<TaxProvider>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2538,9 +3630,15 @@ constructor(
                         newTaxJarConfiguration.additionalProperties.toMutableMap()
                 }
 
-                fun taxExempt(taxExempt: Boolean) = apply { this.taxExempt = taxExempt }
+                fun taxExempt(taxExempt: Boolean) = taxExempt(JsonField.of(taxExempt))
+
+                fun taxExempt(taxExempt: JsonField<Boolean>) = apply { this.taxExempt = taxExempt }
 
-                fun taxProvider(taxProvider: TaxProvider) = apply { this.taxProvider = taxProvider }
+                fun taxProvider(taxProvider: TaxProvider) = taxProvider(JsonField.of(taxProvider))
+
+                fun taxProvider(taxProvider: JsonField<TaxProvider>) = apply {
+                    this.taxProvider = taxProvider
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -2752,23 +3850,44 @@ constructor(
     class TaxId
     @JsonCreator
     private constructor(
-        @JsonProperty("country") private val country: Country,
-        @JsonProperty("type") private val type: Type,
-        @JsonProperty("value") private val value: String,
+        @JsonProperty("country")
+        @ExcludeMissing
+        private val country: JsonField<Country> = JsonMissing.of(),
+        @JsonProperty("type") @ExcludeMissing private val type: JsonField<Type> = JsonMissing.of(),
+        @JsonProperty("value")
+        @ExcludeMissing
+        private val value: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("country") fun country(): Country = country
+        fun country(): Country = country.getRequired("country")
+
+        fun type(): Type = type.getRequired("type")
+
+        fun value(): String = value.getRequired("value")
 
-        @JsonProperty("type") fun type(): Type = type
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("value") fun value(): String = value
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
+
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): TaxId = apply {
+            if (!validated) {
+                country()
+                type()
+                value()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -2778,9 +3897,9 @@ constructor(
 
         class Builder {
 
-            private var country: Country? = null
-            private var type: Type? = null
-            private var value: String? = null
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2791,11 +3910,17 @@ constructor(
                 additionalProperties = taxId.additionalProperties.toMutableMap()
             }
 
-            fun country(country: Country) = apply { this.country = country }
+            fun country(country: Country) = country(JsonField.of(country))
+
+            fun country(country: JsonField<Country>) = apply { this.country = country }
+
+            fun type(type: Type) = type(JsonField.of(type))
+
+            fun type(type: JsonField<Type>) = apply { this.type = type }
 
-            fun type(type: Type) = apply { this.type = type }
+            fun value(value: String) = value(JsonField.of(value))
 
-            fun value(value: String) = apply { this.value = value }
+            fun value(value: JsonField<String>) = apply { this.value = value }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroup.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroup.kt
index 644d2fbc..4d8d57d0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroup.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroup.kt
@@ -68,31 +68,35 @@ private constructor(
     /** The name of the dimensional price group */
     fun name(): String = name.getRequired("name")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * The billable metric associated with this dimensional price group. All prices associated with
      * this dimensional price group will be computed using this billable metric.
      */
-    @JsonProperty("billable_metric_id") @ExcludeMissing fun _billableMetricId() = billableMetricId
+    @JsonProperty("billable_metric_id")
+    @ExcludeMissing
+    fun _billableMetricId(): JsonField<String> = billableMetricId
 
     /** The dimensions that this dimensional price group is defined over */
-    @JsonProperty("dimensions") @ExcludeMissing fun _dimensions() = dimensions
+    @JsonProperty("dimensions")
+    @ExcludeMissing
+    fun _dimensions(): JsonField<List<String>> = dimensions
 
     /** An alias for the dimensional price group */
     @JsonProperty("external_dimensional_price_group_id")
     @ExcludeMissing
-    fun _externalDimensionalPriceGroupId() = externalDimensionalPriceGroupId
+    fun _externalDimensionalPriceGroupId(): JsonField<String> = externalDimensionalPriceGroupId
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The name of the dimensional price group */
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -121,19 +125,19 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var billableMetricId: JsonField<String> = JsonMissing.of()
-        private var dimensions: JsonField<List<String>> = JsonMissing.of()
-        private var externalDimensionalPriceGroupId: JsonField<String> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var billableMetricId: JsonField<String>? = null
+        private var dimensions: JsonField<MutableList<String>>? = null
+        private var externalDimensionalPriceGroupId: JsonField<String>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var name: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(dimensionalPriceGroup: DimensionalPriceGroup) = apply {
             id = dimensionalPriceGroup.id
             billableMetricId = dimensionalPriceGroup.billableMetricId
-            dimensions = dimensionalPriceGroup.dimensions
+            dimensions = dimensionalPriceGroup.dimensions.map { it.toMutableList() }
             externalDimensionalPriceGroupId = dimensionalPriceGroup.externalDimensionalPriceGroupId
             metadata = dimensionalPriceGroup.metadata
             name = dimensionalPriceGroup.name
@@ -163,11 +167,31 @@ private constructor(
         fun dimensions(dimensions: List<String>) = dimensions(JsonField.of(dimensions))
 
         /** The dimensions that this dimensional price group is defined over */
-        fun dimensions(dimensions: JsonField<List<String>>) = apply { this.dimensions = dimensions }
+        fun dimensions(dimensions: JsonField<List<String>>) = apply {
+            this.dimensions = dimensions.map { it.toMutableList() }
+        }
+
+        /** The dimensions that this dimensional price group is defined over */
+        fun addDimension(dimension: String) = apply {
+            dimensions =
+                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(dimension)
+                }
+        }
+
+        /** An alias for the dimensional price group */
+        fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: String?) =
+            externalDimensionalPriceGroupId(JsonField.ofNullable(externalDimensionalPriceGroupId))
 
         /** An alias for the dimensional price group */
-        fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: String) =
-            externalDimensionalPriceGroupId(JsonField.of(externalDimensionalPriceGroupId))
+        fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: Optional<String>) =
+            externalDimensionalPriceGroupId(externalDimensionalPriceGroupId.orElse(null))
 
         /** An alias for the dimensional price group */
         fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: JsonField<String>) =
@@ -216,12 +240,15 @@ private constructor(
 
         fun build(): DimensionalPriceGroup =
             DimensionalPriceGroup(
-                id,
-                billableMetricId,
-                dimensions.map { it.toImmutable() },
-                externalDimensionalPriceGroupId,
-                metadata,
-                name,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(billableMetricId) { "`billableMetricId` is required but was not set" },
+                checkNotNull(dimensions) { "`dimensions` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(externalDimensionalPriceGroupId) {
+                    "`externalDimensionalPriceGroupId` is required but was not set"
+                },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(name) { "`name` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupCreateParams.kt
index fd5c7e13..3d4499f2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupCreateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,15 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * A dimensional price group is used to partition the result of a billable metric by a set of
+ * dimensions. Prices in a price group must specify the parition used to derive their usage.
+ *
+ * For example, suppose we have a billable metric that measures the number of widgets used and we
+ * want to charge differently depending on the color of the widget. We can create a price group with
+ * a dimension "color" and two prices: one that charges $10 per red widget and one that charges $20
+ * per blue widget.
+ */
 class DimensionalPriceGroupCreateParams
 constructor(
     private val body: DimensionalPriceGroupCreateBody,
@@ -39,12 +50,29 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _billableMetricId(): JsonField<String> = body._billableMetricId()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The set of keys (in order) used to disambiguate prices in the group. */
+    fun _dimensions(): JsonField<List<String>> = body._dimensions()
+
+    fun _name(): JsonField<String> = body._name()
+
+    fun _externalDimensionalPriceGroupId(): JsonField<String> =
+        body._externalDimensionalPriceGroupId()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): DimensionalPriceGroupCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -55,38 +83,83 @@ constructor(
     class DimensionalPriceGroupCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("billable_metric_id") private val billableMetricId: String,
-        @JsonProperty("dimensions") private val dimensions: List<String>,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("dimensions")
+        @ExcludeMissing
+        private val dimensions: JsonField<List<String>> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("external_dimensional_price_group_id")
-        private val externalDimensionalPriceGroupId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val externalDimensionalPriceGroupId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("billable_metric_id") fun billableMetricId(): String = billableMetricId
+        fun billableMetricId(): String = billableMetricId.getRequired("billable_metric_id")
 
         /** The set of keys (in order) used to disambiguate prices in the group. */
-        @JsonProperty("dimensions") fun dimensions(): List<String> = dimensions
+        fun dimensions(): List<String> = dimensions.getRequired("dimensions")
 
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
 
-        @JsonProperty("external_dimensional_price_group_id")
         fun externalDimensionalPriceGroupId(): Optional<String> =
-            Optional.ofNullable(externalDimensionalPriceGroupId)
+            Optional.ofNullable(
+                externalDimensionalPriceGroupId.getNullable("external_dimensional_price_group_id")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
+
+        /** The set of keys (in order) used to disambiguate prices in the group. */
+        @JsonProperty("dimensions")
+        @ExcludeMissing
+        fun _dimensions(): JsonField<List<String>> = dimensions
+
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+        @JsonProperty("external_dimensional_price_group_id")
+        @ExcludeMissing
+        fun _externalDimensionalPriceGroupId(): JsonField<String> = externalDimensionalPriceGroupId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): DimensionalPriceGroupCreateBody = apply {
+            if (!validated) {
+                billableMetricId()
+                dimensions()
+                name()
+                externalDimensionalPriceGroupId()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -96,18 +169,19 @@ constructor(
 
         class Builder {
 
-            private var billableMetricId: String? = null
-            private var dimensions: MutableList<String>? = null
-            private var name: String? = null
-            private var externalDimensionalPriceGroupId: String? = null
-            private var metadata: Metadata? = null
+            private var billableMetricId: JsonField<String>? = null
+            private var dimensions: JsonField<MutableList<String>>? = null
+            private var name: JsonField<String>? = null
+            private var externalDimensionalPriceGroupId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(dimensionalPriceGroupCreateBody: DimensionalPriceGroupCreateBody) =
                 apply {
                     billableMetricId = dimensionalPriceGroupCreateBody.billableMetricId
-                    dimensions = dimensionalPriceGroupCreateBody.dimensions.toMutableList()
+                    dimensions =
+                        dimensionalPriceGroupCreateBody.dimensions.map { it.toMutableList() }
                     name = dimensionalPriceGroupCreateBody.name
                     externalDimensionalPriceGroupId =
                         dimensionalPriceGroupCreateBody.externalDimensionalPriceGroupId
@@ -116,35 +190,57 @@ constructor(
                         dimensionalPriceGroupCreateBody.additionalProperties.toMutableMap()
                 }
 
-            fun billableMetricId(billableMetricId: String) = apply {
+            fun billableMetricId(billableMetricId: String) =
+                billableMetricId(JsonField.of(billableMetricId))
+
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
                 this.billableMetricId = billableMetricId
             }
 
             /** The set of keys (in order) used to disambiguate prices in the group. */
-            fun dimensions(dimensions: List<String>) = apply {
-                this.dimensions = dimensions.toMutableList()
+            fun dimensions(dimensions: List<String>) = dimensions(JsonField.of(dimensions))
+
+            /** The set of keys (in order) used to disambiguate prices in the group. */
+            fun dimensions(dimensions: JsonField<List<String>>) = apply {
+                this.dimensions = dimensions.map { it.toMutableList() }
             }
 
             /** The set of keys (in order) used to disambiguate prices in the group. */
             fun addDimension(dimension: String) = apply {
-                dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                dimensions =
+                    (dimensions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(dimension)
+                    }
             }
 
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
 
-            fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: String?) = apply {
-                this.externalDimensionalPriceGroupId = externalDimensionalPriceGroupId
-            }
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: String?) =
+                externalDimensionalPriceGroupId(
+                    JsonField.ofNullable(externalDimensionalPriceGroupId)
+                )
 
             fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: Optional<String>) =
                 externalDimensionalPriceGroupId(externalDimensionalPriceGroupId.orElse(null))
 
+            fun externalDimensionalPriceGroupId(
+                externalDimensionalPriceGroupId: JsonField<String>
+            ) = apply { this.externalDimensionalPriceGroupId = externalDimensionalPriceGroupId }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -153,6 +249,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -178,7 +281,7 @@ constructor(
                         "`billableMetricId` is required but was not set"
                     },
                     checkNotNull(dimensions) { "`dimensions` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     checkNotNull(name) { "`name` is required but was not set" },
                     externalDimensionalPriceGroupId,
                     metadata,
@@ -232,14 +335,23 @@ constructor(
             body.billableMetricId(billableMetricId)
         }
 
+        fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+            body.billableMetricId(billableMetricId)
+        }
+
         /** The set of keys (in order) used to disambiguate prices in the group. */
         fun dimensions(dimensions: List<String>) = apply { body.dimensions(dimensions) }
 
+        /** The set of keys (in order) used to disambiguate prices in the group. */
+        fun dimensions(dimensions: JsonField<List<String>>) = apply { body.dimensions(dimensions) }
+
         /** The set of keys (in order) used to disambiguate prices in the group. */
         fun addDimension(dimension: String) = apply { body.addDimension(dimension) }
 
         fun name(name: String) = apply { body.name(name) }
 
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: String?) = apply {
             body.externalDimensionalPriceGroupId(externalDimensionalPriceGroupId)
         }
@@ -247,6 +359,11 @@ constructor(
         fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: Optional<String>) =
             externalDimensionalPriceGroupId(externalDimensionalPriceGroupId.orElse(null))
 
+        fun externalDimensionalPriceGroupId(externalDimensionalPriceGroupId: JsonField<String>) =
+            apply {
+                body.externalDimensionalPriceGroupId(externalDimensionalPriceGroupId)
+            }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -261,6 +378,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -359,25 +502,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): DimensionalPriceGroupCreateParams =
             DimensionalPriceGroupCreateParams(
                 body.build(),
@@ -403,6 +527,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupExternalDimensionalPriceGroupIdRetrieveParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupExternalDimensionalPriceGroupIdRetrieveParams.kt
index cbefe11c..be93ebe9 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupExternalDimensionalPriceGroupIdRetrieveParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupExternalDimensionalPriceGroupIdRetrieveParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** Fetch dimensional price group by external ID */
 class DimensionalPriceGroupExternalDimensionalPriceGroupIdRetrieveParams
 constructor(
     private val externalDimensionalPriceGroupId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupListParams.kt
index 49453030..62c04965 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupListParams.kt
@@ -8,6 +8,7 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/** List dimensional price groups */
 class DimensionalPriceGroupListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupRetrieveParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupRetrieveParams.kt
index 1c9e6897..ec70cde1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupRetrieveParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroupRetrieveParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** Fetch dimensional price group */
 class DimensionalPriceGroupRetrieveParams
 constructor(
     private val dimensionalPriceGroupId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroups.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroups.kt
index e4a8d5c9..d9fc0418 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroups.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/DimensionalPriceGroups.kt
@@ -33,11 +33,11 @@ private constructor(
     fun paginationMetadata(): PaginationMetadata =
         paginationMetadata.getRequired("pagination_metadata")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<DimensionalPriceGroup>> = data
 
     @JsonProperty("pagination_metadata")
     @ExcludeMissing
-    fun _paginationMetadata() = paginationMetadata
+    fun _paginationMetadata(): JsonField<PaginationMetadata> = paginationMetadata
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -62,20 +62,35 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<DimensionalPriceGroup>> = JsonMissing.of()
-        private var paginationMetadata: JsonField<PaginationMetadata> = JsonMissing.of()
+        private var data: JsonField<MutableList<DimensionalPriceGroup>>? = null
+        private var paginationMetadata: JsonField<PaginationMetadata>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(dimensionalPriceGroups: DimensionalPriceGroups) = apply {
-            data = dimensionalPriceGroups.data
+            data = dimensionalPriceGroups.data.map { it.toMutableList() }
             paginationMetadata = dimensionalPriceGroups.paginationMetadata
             additionalProperties = dimensionalPriceGroups.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<DimensionalPriceGroup>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<DimensionalPriceGroup>>) = apply { this.data = data }
+        fun data(data: JsonField<List<DimensionalPriceGroup>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: DimensionalPriceGroup) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun paginationMetadata(paginationMetadata: PaginationMetadata) =
             paginationMetadata(JsonField.of(paginationMetadata))
@@ -105,8 +120,11 @@ private constructor(
 
         fun build(): DimensionalPriceGroups =
             DimensionalPriceGroups(
-                data.map { it.toImmutable() },
-                paginationMetadata,
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(paginationMetadata) {
+                    "`paginationMetadata` is required but was not set"
+                },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Discount.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Discount.kt
index 2ce7d025..f23bcb84 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Discount.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Discount.kt
@@ -248,17 +248,21 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-        @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+        @JsonProperty("discount_type")
+        @ExcludeMissing
+        fun _discountType(): JsonField<DiscountType> = discountType
 
         /**
          * Only available if discount_type is `usage`. Number of usage units that this discount is
          * for
          */
-        @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+        @JsonProperty("usage_discount")
+        @ExcludeMissing
+        fun _usageDiscount(): JsonField<Double> = usageDiscount
 
-        @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -285,15 +289,15 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var discountType: JsonField<DiscountType> = JsonMissing.of()
-            private var usageDiscount: JsonField<Double> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var discountType: JsonField<DiscountType>? = null
+            private var usageDiscount: JsonField<Double>? = null
             private var reason: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(usageDiscount: UsageDiscount) = apply {
-                appliesToPriceIds = usageDiscount.appliesToPriceIds
+                appliesToPriceIds = usageDiscount.appliesToPriceIds.map { it.toMutableList() }
                 discountType = usageDiscount.discountType
                 this.usageDiscount = usageDiscount.usageDiscount
                 reason = usageDiscount.reason
@@ -312,7 +316,24 @@ private constructor(
              * can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this discount applies to. For plan/plan phase discounts, this
+             * can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             fun discountType(discountType: DiscountType) = discountType(JsonField.of(discountType))
@@ -335,7 +356,9 @@ private constructor(
                 this.usageDiscount = usageDiscount
             }
 
-            fun reason(reason: String) = reason(JsonField.of(reason))
+            fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+            fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
             fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -360,9 +383,12 @@ private constructor(
 
             fun build(): UsageDiscount =
                 UsageDiscount(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    discountType,
-                    usageDiscount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(discountType) { "`discountType` is required but was not set" },
+                    checkNotNull(usageDiscount) { "`usageDiscount` is required but was not set" },
                     reason,
                     additionalProperties.toImmutable(),
                 )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EvaluatePriceGroup.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EvaluatePriceGroup.kt
index 2393d25a..6d778468 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EvaluatePriceGroup.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EvaluatePriceGroup.kt
@@ -53,13 +53,15 @@ private constructor(
     fun quantity(): Double = quantity.getRequired("quantity")
 
     /** The price's output for the group */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
     /** The values for the group in the order specified by `grouping_keys` */
-    @JsonProperty("grouping_values") @ExcludeMissing fun _groupingValues() = groupingValues
+    @JsonProperty("grouping_values")
+    @ExcludeMissing
+    fun _groupingValues(): JsonField<List<GroupingValue>> = groupingValues
 
     /** The price's usage quantity for the group */
-    @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+    @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -85,15 +87,15 @@ private constructor(
 
     class Builder {
 
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var groupingValues: JsonField<List<GroupingValue>> = JsonMissing.of()
-        private var quantity: JsonField<Double> = JsonMissing.of()
+        private var amount: JsonField<String>? = null
+        private var groupingValues: JsonField<MutableList<GroupingValue>>? = null
+        private var quantity: JsonField<Double>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(evaluatePriceGroup: EvaluatePriceGroup) = apply {
             amount = evaluatePriceGroup.amount
-            groupingValues = evaluatePriceGroup.groupingValues
+            groupingValues = evaluatePriceGroup.groupingValues.map { it.toMutableList() }
             quantity = evaluatePriceGroup.quantity
             additionalProperties = evaluatePriceGroup.additionalProperties.toMutableMap()
         }
@@ -110,7 +112,21 @@ private constructor(
 
         /** The values for the group in the order specified by `grouping_keys` */
         fun groupingValues(groupingValues: JsonField<List<GroupingValue>>) = apply {
-            this.groupingValues = groupingValues
+            this.groupingValues = groupingValues.map { it.toMutableList() }
+        }
+
+        /** The values for the group in the order specified by `grouping_keys` */
+        fun addGroupingValue(groupingValue: GroupingValue) = apply {
+            groupingValues =
+                (groupingValues ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(groupingValue)
+                }
         }
 
         /** The price's usage quantity for the group */
@@ -140,9 +156,10 @@ private constructor(
 
         fun build(): EvaluatePriceGroup =
             EvaluatePriceGroup(
-                amount,
-                groupingValues.map { it.toImmutable() },
-                quantity,
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(groupingValues) { "`groupingValues` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(quantity) { "`quantity` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseParams.kt
index b7032634..ad84ec37 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseParams.kt
@@ -10,6 +10,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Closing a backfill makes the updated usage visible in Orb. Upon closing a backfill, Orb will
+ * asynchronously reflect the updated usage in invoice amounts and usage graphs. Once all of the
+ * updates are complete, the backfill's status will transition to `reflected`.
+ */
 class EventBackfillCloseParams
 constructor(
     private val backfillId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseResponse.kt
index 5fe6c161..ebd49557 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCloseResponse.kt
@@ -96,40 +96,54 @@ private constructor(
     fun deprecationFilter(): Optional<String> =
         Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * If in the future, the time at which the backfill will automatically close. If in the past,
      * the time at which the backfill was closed.
      */
-    @JsonProperty("close_time") @ExcludeMissing fun _closeTime() = closeTime
+    @JsonProperty("close_time")
+    @ExcludeMissing
+    fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
      * backfill is scoped to all customers.
      */
-    @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+    @JsonProperty("customer_id") @ExcludeMissing fun _customerId(): JsonField<String> = customerId
 
     /** The number of events ingested in this backfill. */
-    @JsonProperty("events_ingested") @ExcludeMissing fun _eventsIngested() = eventsIngested
+    @JsonProperty("events_ingested")
+    @ExcludeMissing
+    fun _eventsIngested(): JsonField<Long> = eventsIngested
 
     /** The time at which this backfill was reverted. */
-    @JsonProperty("reverted_at") @ExcludeMissing fun _revertedAt() = revertedAt
+    @JsonProperty("reverted_at")
+    @ExcludeMissing
+    fun _revertedAt(): JsonField<OffsetDateTime> = revertedAt
 
     /** The status of the backfill. */
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+    @JsonProperty("timeframe_end")
+    @ExcludeMissing
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-    @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+    @JsonProperty("timeframe_start")
+    @ExcludeMissing
+    fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
     /**
      * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
      * used to filter the set of events to deprecate
      */
-    @JsonProperty("deprecation_filter") @ExcludeMissing fun _deprecationFilter() = deprecationFilter
+    @JsonProperty("deprecation_filter")
+    @ExcludeMissing
+    fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -162,15 +176,15 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customerId: JsonField<String> = JsonMissing.of()
-        private var eventsIngested: JsonField<Long> = JsonMissing.of()
-        private var revertedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var closeTime: JsonField<OffsetDateTime>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var customerId: JsonField<String>? = null
+        private var eventsIngested: JsonField<Long>? = null
+        private var revertedAt: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var timeframeEnd: JsonField<OffsetDateTime>? = null
+        private var timeframeStart: JsonField<OffsetDateTime>? = null
         private var deprecationFilter: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -197,7 +211,13 @@ private constructor(
          * If in the future, the time at which the backfill will automatically close. If in the
          * past, the time at which the backfill was closed.
          */
-        fun closeTime(closeTime: OffsetDateTime) = closeTime(JsonField.of(closeTime))
+        fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
+
+        /**
+         * If in the future, the time at which the backfill will automatically close. If in the
+         * past, the time at which the backfill was closed.
+         */
+        fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
         /**
          * If in the future, the time at which the backfill will automatically close. If in the
@@ -213,7 +233,13 @@ private constructor(
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
          * backfill is scoped to all customers.
          */
-        fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+        fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
+         * backfill is scoped to all customers.
+         */
+        fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
@@ -230,7 +256,10 @@ private constructor(
         }
 
         /** The time at which this backfill was reverted. */
-        fun revertedAt(revertedAt: OffsetDateTime) = revertedAt(JsonField.of(revertedAt))
+        fun revertedAt(revertedAt: OffsetDateTime?) = revertedAt(JsonField.ofNullable(revertedAt))
+
+        /** The time at which this backfill was reverted. */
+        fun revertedAt(revertedAt: Optional<OffsetDateTime>) = revertedAt(revertedAt.orElse(null))
 
         /** The time at which this backfill was reverted. */
         fun revertedAt(revertedAt: JsonField<OffsetDateTime>) = apply {
@@ -261,8 +290,16 @@ private constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the set of events to deprecate
          */
-        fun deprecationFilter(deprecationFilter: String) =
-            deprecationFilter(JsonField.of(deprecationFilter))
+        fun deprecationFilter(deprecationFilter: String?) =
+            deprecationFilter(JsonField.ofNullable(deprecationFilter))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: Optional<String>) =
+            deprecationFilter(deprecationFilter.orElse(null))
 
         /**
          * A boolean
@@ -294,15 +331,15 @@ private constructor(
 
         fun build(): EventBackfillCloseResponse =
             EventBackfillCloseResponse(
-                id,
-                closeTime,
-                createdAt,
-                customerId,
-                eventsIngested,
-                revertedAt,
-                status,
-                timeframeEnd,
-                timeframeStart,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(closeTime) { "`closeTime` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(customerId) { "`customerId` is required but was not set" },
+                checkNotNull(eventsIngested) { "`eventsIngested` is required but was not set" },
+                checkNotNull(revertedAt) { "`revertedAt` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                 deprecationFilter,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateParams.kt
index 40e0aa63..e07a6c93 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,36 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Creating the backfill enables adding or replacing past events, even those that are older than the
+ * ingestion grace period. Performing a backfill in Orb involves 3 steps:
+ * 1. Create the backfill, specifying its parameters.
+ * 2. [Ingest](ingest) usage events, referencing the backfill (query parameter `backfill_id`).
+ * 3. [Close](close-backfill) the backfill, propagating the update in past usage throughout Orb.
+ *
+ * Changes from a backfill are not reflected until the backfill is closed, so you won’t need to
+ * worry about your customers seeing partially updated usage data. Backfills are also reversible, so
+ * you’ll be able to revert a backfill if you’ve made a mistake.
+ *
+ * This endpoint will return a backfill object, which contains an `id`. That `id` can then be used
+ * as the `backfill_id` query parameter to the event ingestion endpoint to associate ingested events
+ * with this backfill. The effects (e.g. updated usage graphs) of this backfill will not take place
+ * until the backfill is closed.
+ *
+ * If the `replace_existing_events` is `true`, existing events in the backfill's timeframe will be
+ * replaced with the newly ingested events associated with the backfill. If `false`, newly ingested
+ * events will be added to the existing events.
+ *
+ * If a `customer_id` or `external_customer_id` is specified, the backfill will only affect events
+ * for that customer. If neither is specified, the backfill will affect all customers.
+ *
+ * When `replace_existing_events` is `true`, this indicates that existing events in the timeframe
+ * should no longer be counted towards invoiced usage. In this scenario, the parameter `filter` can
+ * be optionally added which enables filtering using
+ * [computed properties](../guides/extensibility/advanced-metrics#computed-properties). The
+ * expressiveness of computed properties allows you to deprecate existing events based on both a
+ * period of time and specific property values.
+ */
 class EventBackfillCreateParams
 constructor(
     private val body: EventBackfillCreateBody,
@@ -61,12 +93,49 @@ constructor(
      */
     fun replaceExistingEvents(): Optional<Boolean> = body.replaceExistingEvents()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The (exclusive) end of the usage timeframe affected by this backfill. */
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = body._timeframeEnd()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The (inclusive) start of the usage timeframe affected by this backfill. */
+    fun _timeframeStart(): JsonField<OffsetDateTime> = body._timeframeStart()
+
+    /**
+     * The time at which no more events will be accepted for this backfill. The backfill will
+     * automatically begin reflecting throughout Orb at the close time. If not specified, it will
+     * default to 1 day after the creation of the backfill.
+     */
+    fun _closeTime(): JsonField<OffsetDateTime> = body._closeTime()
+
+    /**
+     * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this field
+     * will scope the backfill to all customers.
+     */
+    fun _customerId(): JsonField<String> = body._customerId()
+
+    /**
+     * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
+     * used to filter the set of events to deprecate
+     */
+    fun _deprecationFilter(): JsonField<String> = body._deprecationFilter()
+
+    /**
+     * The external customer ID of the customer to which this backfill is scoped. Omitting this
+     * field will scope the backfill to all customers.
+     */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /**
+     * If true, replaces all existing events in the timeframe with the newly ingested events. If
+     * false, adds the newly ingested events to the existing events.
+     */
+    fun _replaceExistingEvents(): JsonField<Boolean> = body._replaceExistingEvents()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): EventBackfillCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -77,22 +146,83 @@ constructor(
     class EventBackfillCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("timeframe_end") private val timeframeEnd: OffsetDateTime,
-        @JsonProperty("timeframe_start") private val timeframeStart: OffsetDateTime,
-        @JsonProperty("close_time") private val closeTime: OffsetDateTime?,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("deprecation_filter") private val deprecationFilter: String?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("replace_existing_events") private val replaceExistingEvents: Boolean?,
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        private val timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        private val timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("close_time")
+        @ExcludeMissing
+        private val closeTime: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("deprecation_filter")
+        @ExcludeMissing
+        private val deprecationFilter: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("replace_existing_events")
+        @ExcludeMissing
+        private val replaceExistingEvents: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The (exclusive) end of the usage timeframe affected by this backfill. */
-        @JsonProperty("timeframe_end") fun timeframeEnd(): OffsetDateTime = timeframeEnd
+        fun timeframeEnd(): OffsetDateTime = timeframeEnd.getRequired("timeframe_end")
 
         /** The (inclusive) start of the usage timeframe affected by this backfill. */
-        @JsonProperty("timeframe_start") fun timeframeStart(): OffsetDateTime = timeframeStart
+        fun timeframeStart(): OffsetDateTime = timeframeStart.getRequired("timeframe_start")
+
+        /**
+         * The time at which no more events will be accepted for this backfill. The backfill will
+         * automatically begin reflecting throughout Orb at the close time. If not specified, it
+         * will default to 1 day after the creation of the backfill.
+         */
+        fun closeTime(): Optional<OffsetDateTime> =
+            Optional.ofNullable(closeTime.getNullable("close_time"))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
+         * field will scope the backfill to all customers.
+         */
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(): Optional<String> =
+            Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
+
+        /**
+         * The external customer ID of the customer to which this backfill is scoped. Omitting this
+         * field will scope the backfill to all customers.
+         */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /**
+         * If true, replaces all existing events in the timeframe with the newly ingested events. If
+         * false, adds the newly ingested events to the existing events.
+         */
+        fun replaceExistingEvents(): Optional<Boolean> =
+            Optional.ofNullable(replaceExistingEvents.getNullable("replace_existing_events"))
+
+        /** The (exclusive) end of the usage timeframe affected by this backfill. */
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
+
+        /** The (inclusive) start of the usage timeframe affected by this backfill. */
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         /**
          * The time at which no more events will be accepted for this backfill. The backfill will
@@ -100,14 +230,16 @@ constructor(
          * will default to 1 day after the creation of the backfill.
          */
         @JsonProperty("close_time")
-        fun closeTime(): Optional<OffsetDateTime> = Optional.ofNullable(closeTime)
+        @ExcludeMissing
+        fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
          * field will scope the backfill to all customers.
          */
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /**
          * A boolean
@@ -115,26 +247,44 @@ constructor(
          * filter the set of events to deprecate
          */
         @JsonProperty("deprecation_filter")
-        fun deprecationFilter(): Optional<String> = Optional.ofNullable(deprecationFilter)
+        @ExcludeMissing
+        fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
         /**
          * The external customer ID of the customer to which this backfill is scoped. Omitting this
          * field will scope the backfill to all customers.
          */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * If true, replaces all existing events in the timeframe with the newly ingested events. If
          * false, adds the newly ingested events to the existing events.
          */
         @JsonProperty("replace_existing_events")
-        fun replaceExistingEvents(): Optional<Boolean> = Optional.ofNullable(replaceExistingEvents)
+        @ExcludeMissing
+        fun _replaceExistingEvents(): JsonField<Boolean> = replaceExistingEvents
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): EventBackfillCreateBody = apply {
+            if (!validated) {
+                timeframeEnd()
+                timeframeStart()
+                closeTime()
+                customerId()
+                deprecationFilter()
+                externalCustomerId()
+                replaceExistingEvents()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -144,13 +294,13 @@ constructor(
 
         class Builder {
 
-            private var timeframeEnd: OffsetDateTime? = null
-            private var timeframeStart: OffsetDateTime? = null
-            private var closeTime: OffsetDateTime? = null
-            private var customerId: String? = null
-            private var deprecationFilter: String? = null
-            private var externalCustomerId: String? = null
-            private var replaceExistingEvents: Boolean? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
+            private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var deprecationFilter: JsonField<String> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var replaceExistingEvents: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -166,12 +316,20 @@ constructor(
             }
 
             /** The (exclusive) end of the usage timeframe affected by this backfill. */
-            fun timeframeEnd(timeframeEnd: OffsetDateTime) = apply {
+            fun timeframeEnd(timeframeEnd: OffsetDateTime) =
+                timeframeEnd(JsonField.of(timeframeEnd))
+
+            /** The (exclusive) end of the usage timeframe affected by this backfill. */
+            fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
                 this.timeframeEnd = timeframeEnd
             }
 
             /** The (inclusive) start of the usage timeframe affected by this backfill. */
-            fun timeframeStart(timeframeStart: OffsetDateTime) = apply {
+            fun timeframeStart(timeframeStart: OffsetDateTime) =
+                timeframeStart(JsonField.of(timeframeStart))
+
+            /** The (inclusive) start of the usage timeframe affected by this backfill. */
+            fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
                 this.timeframeStart = timeframeStart
             }
 
@@ -180,7 +338,7 @@ constructor(
              * will automatically begin reflecting throughout Orb at the close time. If not
              * specified, it will default to 1 day after the creation of the backfill.
              */
-            fun closeTime(closeTime: OffsetDateTime?) = apply { this.closeTime = closeTime }
+            fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
 
             /**
              * The time at which no more events will be accepted for this backfill. The backfill
@@ -189,11 +347,20 @@ constructor(
              */
             fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
+            /**
+             * The time at which no more events will be accepted for this backfill. The backfill
+             * will automatically begin reflecting throughout Orb at the close time. If not
+             * specified, it will default to 1 day after the creation of the backfill.
+             */
+            fun closeTime(closeTime: JsonField<OffsetDateTime>) = apply {
+                this.closeTime = closeTime
+            }
+
             /**
              * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
              * field will scope the backfill to all customers.
              */
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             /**
              * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
@@ -201,14 +368,19 @@ constructor(
              */
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            /**
+             * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
+             * field will scope the backfill to all customers.
+             */
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /**
              * A boolean
              * [computed property](../guides/extensibility/advanced-metrics#computed-properties)
              * used to filter the set of events to deprecate
              */
-            fun deprecationFilter(deprecationFilter: String?) = apply {
-                this.deprecationFilter = deprecationFilter
-            }
+            fun deprecationFilter(deprecationFilter: String?) =
+                deprecationFilter(JsonField.ofNullable(deprecationFilter))
 
             /**
              * A boolean
@@ -218,13 +390,21 @@ constructor(
             fun deprecationFilter(deprecationFilter: Optional<String>) =
                 deprecationFilter(deprecationFilter.orElse(null))
 
+            /**
+             * A boolean
+             * [computed property](../guides/extensibility/advanced-metrics#computed-properties)
+             * used to filter the set of events to deprecate
+             */
+            fun deprecationFilter(deprecationFilter: JsonField<String>) = apply {
+                this.deprecationFilter = deprecationFilter
+            }
+
             /**
              * The external customer ID of the customer to which this backfill is scoped. Omitting
              * this field will scope the backfill to all customers.
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * The external customer ID of the customer to which this backfill is scoped. Omitting
@@ -234,11 +414,11 @@ constructor(
                 externalCustomerId(externalCustomerId.orElse(null))
 
             /**
-             * If true, replaces all existing events in the timeframe with the newly ingested
-             * events. If false, adds the newly ingested events to the existing events.
+             * The external customer ID of the customer to which this backfill is scoped. Omitting
+             * this field will scope the backfill to all customers.
              */
-            fun replaceExistingEvents(replaceExistingEvents: Boolean?) = apply {
-                this.replaceExistingEvents = replaceExistingEvents
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
             }
 
             /**
@@ -246,15 +426,15 @@ constructor(
              * events. If false, adds the newly ingested events to the existing events.
              */
             fun replaceExistingEvents(replaceExistingEvents: Boolean) =
-                replaceExistingEvents(replaceExistingEvents as Boolean?)
+                replaceExistingEvents(JsonField.of(replaceExistingEvents))
 
             /**
              * If true, replaces all existing events in the timeframe with the newly ingested
              * events. If false, adds the newly ingested events to the existing events.
              */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun replaceExistingEvents(replaceExistingEvents: Optional<Boolean>) =
-                replaceExistingEvents(replaceExistingEvents.orElse(null) as Boolean?)
+            fun replaceExistingEvents(replaceExistingEvents: JsonField<Boolean>) = apply {
+                this.replaceExistingEvents = replaceExistingEvents
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -330,11 +510,21 @@ constructor(
         /** The (exclusive) end of the usage timeframe affected by this backfill. */
         fun timeframeEnd(timeframeEnd: OffsetDateTime) = apply { body.timeframeEnd(timeframeEnd) }
 
+        /** The (exclusive) end of the usage timeframe affected by this backfill. */
+        fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
+            body.timeframeEnd(timeframeEnd)
+        }
+
         /** The (inclusive) start of the usage timeframe affected by this backfill. */
         fun timeframeStart(timeframeStart: OffsetDateTime) = apply {
             body.timeframeStart(timeframeStart)
         }
 
+        /** The (inclusive) start of the usage timeframe affected by this backfill. */
+        fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
+            body.timeframeStart(timeframeStart)
+        }
+
         /**
          * The time at which no more events will be accepted for this backfill. The backfill will
          * automatically begin reflecting throughout Orb at the close time. If not specified, it
@@ -349,6 +539,13 @@ constructor(
          */
         fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
+        /**
+         * The time at which no more events will be accepted for this backfill. The backfill will
+         * automatically begin reflecting throughout Orb at the close time. If not specified, it
+         * will default to 1 day after the creation of the backfill.
+         */
+        fun closeTime(closeTime: JsonField<OffsetDateTime>) = apply { body.closeTime(closeTime) }
+
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
          * field will scope the backfill to all customers.
@@ -361,6 +558,12 @@ constructor(
          */
         fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. Omitting this
+         * field will scope the backfill to all customers.
+         */
+        fun customerId(customerId: JsonField<String>) = apply { body.customerId(customerId) }
+
         /**
          * A boolean
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
@@ -378,6 +581,15 @@ constructor(
         fun deprecationFilter(deprecationFilter: Optional<String>) =
             deprecationFilter(deprecationFilter.orElse(null))
 
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: JsonField<String>) = apply {
+            body.deprecationFilter(deprecationFilter)
+        }
+
         /**
          * The external customer ID of the customer to which this backfill is scoped. Omitting this
          * field will scope the backfill to all customers.
@@ -394,27 +606,47 @@ constructor(
             externalCustomerId(externalCustomerId.orElse(null))
 
         /**
-         * If true, replaces all existing events in the timeframe with the newly ingested events. If
-         * false, adds the newly ingested events to the existing events.
+         * The external customer ID of the customer to which this backfill is scoped. Omitting this
+         * field will scope the backfill to all customers.
          */
-        fun replaceExistingEvents(replaceExistingEvents: Boolean?) = apply {
-            body.replaceExistingEvents(replaceExistingEvents)
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
         }
 
         /**
          * If true, replaces all existing events in the timeframe with the newly ingested events. If
          * false, adds the newly ingested events to the existing events.
          */
-        fun replaceExistingEvents(replaceExistingEvents: Boolean) =
-            replaceExistingEvents(replaceExistingEvents as Boolean?)
+        fun replaceExistingEvents(replaceExistingEvents: Boolean) = apply {
+            body.replaceExistingEvents(replaceExistingEvents)
+        }
 
         /**
          * If true, replaces all existing events in the timeframe with the newly ingested events. If
          * false, adds the newly ingested events to the existing events.
          */
-        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-        fun replaceExistingEvents(replaceExistingEvents: Optional<Boolean>) =
-            replaceExistingEvents(replaceExistingEvents.orElse(null) as Boolean?)
+        fun replaceExistingEvents(replaceExistingEvents: JsonField<Boolean>) = apply {
+            body.replaceExistingEvents(replaceExistingEvents)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -514,25 +746,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): EventBackfillCreateParams =
             EventBackfillCreateParams(
                 body.build(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateResponse.kt
index ddc3fdd2..66bad85a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillCreateResponse.kt
@@ -96,40 +96,54 @@ private constructor(
     fun deprecationFilter(): Optional<String> =
         Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * If in the future, the time at which the backfill will automatically close. If in the past,
      * the time at which the backfill was closed.
      */
-    @JsonProperty("close_time") @ExcludeMissing fun _closeTime() = closeTime
+    @JsonProperty("close_time")
+    @ExcludeMissing
+    fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
      * backfill is scoped to all customers.
      */
-    @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+    @JsonProperty("customer_id") @ExcludeMissing fun _customerId(): JsonField<String> = customerId
 
     /** The number of events ingested in this backfill. */
-    @JsonProperty("events_ingested") @ExcludeMissing fun _eventsIngested() = eventsIngested
+    @JsonProperty("events_ingested")
+    @ExcludeMissing
+    fun _eventsIngested(): JsonField<Long> = eventsIngested
 
     /** The time at which this backfill was reverted. */
-    @JsonProperty("reverted_at") @ExcludeMissing fun _revertedAt() = revertedAt
+    @JsonProperty("reverted_at")
+    @ExcludeMissing
+    fun _revertedAt(): JsonField<OffsetDateTime> = revertedAt
 
     /** The status of the backfill. */
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+    @JsonProperty("timeframe_end")
+    @ExcludeMissing
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-    @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+    @JsonProperty("timeframe_start")
+    @ExcludeMissing
+    fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
     /**
      * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
      * used to filter the set of events to deprecate
      */
-    @JsonProperty("deprecation_filter") @ExcludeMissing fun _deprecationFilter() = deprecationFilter
+    @JsonProperty("deprecation_filter")
+    @ExcludeMissing
+    fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -162,15 +176,15 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customerId: JsonField<String> = JsonMissing.of()
-        private var eventsIngested: JsonField<Long> = JsonMissing.of()
-        private var revertedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var closeTime: JsonField<OffsetDateTime>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var customerId: JsonField<String>? = null
+        private var eventsIngested: JsonField<Long>? = null
+        private var revertedAt: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var timeframeEnd: JsonField<OffsetDateTime>? = null
+        private var timeframeStart: JsonField<OffsetDateTime>? = null
         private var deprecationFilter: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -197,7 +211,13 @@ private constructor(
          * If in the future, the time at which the backfill will automatically close. If in the
          * past, the time at which the backfill was closed.
          */
-        fun closeTime(closeTime: OffsetDateTime) = closeTime(JsonField.of(closeTime))
+        fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
+
+        /**
+         * If in the future, the time at which the backfill will automatically close. If in the
+         * past, the time at which the backfill was closed.
+         */
+        fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
         /**
          * If in the future, the time at which the backfill will automatically close. If in the
@@ -213,7 +233,13 @@ private constructor(
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
          * backfill is scoped to all customers.
          */
-        fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+        fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
+         * backfill is scoped to all customers.
+         */
+        fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
@@ -230,7 +256,10 @@ private constructor(
         }
 
         /** The time at which this backfill was reverted. */
-        fun revertedAt(revertedAt: OffsetDateTime) = revertedAt(JsonField.of(revertedAt))
+        fun revertedAt(revertedAt: OffsetDateTime?) = revertedAt(JsonField.ofNullable(revertedAt))
+
+        /** The time at which this backfill was reverted. */
+        fun revertedAt(revertedAt: Optional<OffsetDateTime>) = revertedAt(revertedAt.orElse(null))
 
         /** The time at which this backfill was reverted. */
         fun revertedAt(revertedAt: JsonField<OffsetDateTime>) = apply {
@@ -261,8 +290,16 @@ private constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the set of events to deprecate
          */
-        fun deprecationFilter(deprecationFilter: String) =
-            deprecationFilter(JsonField.of(deprecationFilter))
+        fun deprecationFilter(deprecationFilter: String?) =
+            deprecationFilter(JsonField.ofNullable(deprecationFilter))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: Optional<String>) =
+            deprecationFilter(deprecationFilter.orElse(null))
 
         /**
          * A boolean
@@ -294,15 +331,15 @@ private constructor(
 
         fun build(): EventBackfillCreateResponse =
             EventBackfillCreateResponse(
-                id,
-                closeTime,
-                createdAt,
-                customerId,
-                eventsIngested,
-                revertedAt,
-                status,
-                timeframeEnd,
-                timeframeStart,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(closeTime) { "`closeTime` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(customerId) { "`customerId` is required but was not set" },
+                checkNotNull(eventsIngested) { "`eventsIngested` is required but was not set" },
+                checkNotNull(revertedAt) { "`revertedAt` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                 deprecationFilter,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchParams.kt
index fc90e84e..60548af8 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** This endpoint is used to fetch a backfill given an identifier. */
 class EventBackfillFetchParams
 constructor(
     private val backfillId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchResponse.kt
index 5cb414a5..def03bad 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillFetchResponse.kt
@@ -96,40 +96,54 @@ private constructor(
     fun deprecationFilter(): Optional<String> =
         Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * If in the future, the time at which the backfill will automatically close. If in the past,
      * the time at which the backfill was closed.
      */
-    @JsonProperty("close_time") @ExcludeMissing fun _closeTime() = closeTime
+    @JsonProperty("close_time")
+    @ExcludeMissing
+    fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
      * backfill is scoped to all customers.
      */
-    @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+    @JsonProperty("customer_id") @ExcludeMissing fun _customerId(): JsonField<String> = customerId
 
     /** The number of events ingested in this backfill. */
-    @JsonProperty("events_ingested") @ExcludeMissing fun _eventsIngested() = eventsIngested
+    @JsonProperty("events_ingested")
+    @ExcludeMissing
+    fun _eventsIngested(): JsonField<Long> = eventsIngested
 
     /** The time at which this backfill was reverted. */
-    @JsonProperty("reverted_at") @ExcludeMissing fun _revertedAt() = revertedAt
+    @JsonProperty("reverted_at")
+    @ExcludeMissing
+    fun _revertedAt(): JsonField<OffsetDateTime> = revertedAt
 
     /** The status of the backfill. */
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+    @JsonProperty("timeframe_end")
+    @ExcludeMissing
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-    @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+    @JsonProperty("timeframe_start")
+    @ExcludeMissing
+    fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
     /**
      * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
      * used to filter the set of events to deprecate
      */
-    @JsonProperty("deprecation_filter") @ExcludeMissing fun _deprecationFilter() = deprecationFilter
+    @JsonProperty("deprecation_filter")
+    @ExcludeMissing
+    fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -162,15 +176,15 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customerId: JsonField<String> = JsonMissing.of()
-        private var eventsIngested: JsonField<Long> = JsonMissing.of()
-        private var revertedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var closeTime: JsonField<OffsetDateTime>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var customerId: JsonField<String>? = null
+        private var eventsIngested: JsonField<Long>? = null
+        private var revertedAt: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var timeframeEnd: JsonField<OffsetDateTime>? = null
+        private var timeframeStart: JsonField<OffsetDateTime>? = null
         private var deprecationFilter: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -197,7 +211,13 @@ private constructor(
          * If in the future, the time at which the backfill will automatically close. If in the
          * past, the time at which the backfill was closed.
          */
-        fun closeTime(closeTime: OffsetDateTime) = closeTime(JsonField.of(closeTime))
+        fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
+
+        /**
+         * If in the future, the time at which the backfill will automatically close. If in the
+         * past, the time at which the backfill was closed.
+         */
+        fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
         /**
          * If in the future, the time at which the backfill will automatically close. If in the
@@ -213,7 +233,13 @@ private constructor(
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
          * backfill is scoped to all customers.
          */
-        fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+        fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
+         * backfill is scoped to all customers.
+         */
+        fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
@@ -230,7 +256,10 @@ private constructor(
         }
 
         /** The time at which this backfill was reverted. */
-        fun revertedAt(revertedAt: OffsetDateTime) = revertedAt(JsonField.of(revertedAt))
+        fun revertedAt(revertedAt: OffsetDateTime?) = revertedAt(JsonField.ofNullable(revertedAt))
+
+        /** The time at which this backfill was reverted. */
+        fun revertedAt(revertedAt: Optional<OffsetDateTime>) = revertedAt(revertedAt.orElse(null))
 
         /** The time at which this backfill was reverted. */
         fun revertedAt(revertedAt: JsonField<OffsetDateTime>) = apply {
@@ -261,8 +290,16 @@ private constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the set of events to deprecate
          */
-        fun deprecationFilter(deprecationFilter: String) =
-            deprecationFilter(JsonField.of(deprecationFilter))
+        fun deprecationFilter(deprecationFilter: String?) =
+            deprecationFilter(JsonField.ofNullable(deprecationFilter))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: Optional<String>) =
+            deprecationFilter(deprecationFilter.orElse(null))
 
         /**
          * A boolean
@@ -294,15 +331,15 @@ private constructor(
 
         fun build(): EventBackfillFetchResponse =
             EventBackfillFetchResponse(
-                id,
-                closeTime,
-                createdAt,
-                customerId,
-                eventsIngested,
-                revertedAt,
-                status,
-                timeframeEnd,
-                timeframeStart,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(closeTime) { "`closeTime` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(customerId) { "`customerId` is required but was not set" },
+                checkNotNull(eventsIngested) { "`eventsIngested` is required but was not set" },
+                checkNotNull(revertedAt) { "`revertedAt` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                 deprecationFilter,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListParams.kt
index 40adf5c5..dd55dab5 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListParams.kt
@@ -8,6 +8,14 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all backfills in a list format.
+ *
+ * The list of backfills is ordered starting from the most recently created backfill. The response
+ * also includes [`pagination_metadata`](../reference/pagination), which lets the caller retrieve
+ * the next page of results if they exist. More information about pagination can be found in the
+ * [Pagination-metadata schema](pagination).
+ */
 class EventBackfillListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListResponse.kt
index 0ba3a719..b82d4048 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillListResponse.kt
@@ -96,40 +96,54 @@ private constructor(
     fun deprecationFilter(): Optional<String> =
         Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * If in the future, the time at which the backfill will automatically close. If in the past,
      * the time at which the backfill was closed.
      */
-    @JsonProperty("close_time") @ExcludeMissing fun _closeTime() = closeTime
+    @JsonProperty("close_time")
+    @ExcludeMissing
+    fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
      * backfill is scoped to all customers.
      */
-    @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+    @JsonProperty("customer_id") @ExcludeMissing fun _customerId(): JsonField<String> = customerId
 
     /** The number of events ingested in this backfill. */
-    @JsonProperty("events_ingested") @ExcludeMissing fun _eventsIngested() = eventsIngested
+    @JsonProperty("events_ingested")
+    @ExcludeMissing
+    fun _eventsIngested(): JsonField<Long> = eventsIngested
 
     /** The time at which this backfill was reverted. */
-    @JsonProperty("reverted_at") @ExcludeMissing fun _revertedAt() = revertedAt
+    @JsonProperty("reverted_at")
+    @ExcludeMissing
+    fun _revertedAt(): JsonField<OffsetDateTime> = revertedAt
 
     /** The status of the backfill. */
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+    @JsonProperty("timeframe_end")
+    @ExcludeMissing
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-    @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+    @JsonProperty("timeframe_start")
+    @ExcludeMissing
+    fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
     /**
      * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
      * used to filter the set of events to deprecate
      */
-    @JsonProperty("deprecation_filter") @ExcludeMissing fun _deprecationFilter() = deprecationFilter
+    @JsonProperty("deprecation_filter")
+    @ExcludeMissing
+    fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -162,15 +176,15 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customerId: JsonField<String> = JsonMissing.of()
-        private var eventsIngested: JsonField<Long> = JsonMissing.of()
-        private var revertedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var closeTime: JsonField<OffsetDateTime>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var customerId: JsonField<String>? = null
+        private var eventsIngested: JsonField<Long>? = null
+        private var revertedAt: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var timeframeEnd: JsonField<OffsetDateTime>? = null
+        private var timeframeStart: JsonField<OffsetDateTime>? = null
         private var deprecationFilter: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -197,7 +211,13 @@ private constructor(
          * If in the future, the time at which the backfill will automatically close. If in the
          * past, the time at which the backfill was closed.
          */
-        fun closeTime(closeTime: OffsetDateTime) = closeTime(JsonField.of(closeTime))
+        fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
+
+        /**
+         * If in the future, the time at which the backfill will automatically close. If in the
+         * past, the time at which the backfill was closed.
+         */
+        fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
         /**
          * If in the future, the time at which the backfill will automatically close. If in the
@@ -213,7 +233,13 @@ private constructor(
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
          * backfill is scoped to all customers.
          */
-        fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+        fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
+         * backfill is scoped to all customers.
+         */
+        fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
@@ -230,7 +256,10 @@ private constructor(
         }
 
         /** The time at which this backfill was reverted. */
-        fun revertedAt(revertedAt: OffsetDateTime) = revertedAt(JsonField.of(revertedAt))
+        fun revertedAt(revertedAt: OffsetDateTime?) = revertedAt(JsonField.ofNullable(revertedAt))
+
+        /** The time at which this backfill was reverted. */
+        fun revertedAt(revertedAt: Optional<OffsetDateTime>) = revertedAt(revertedAt.orElse(null))
 
         /** The time at which this backfill was reverted. */
         fun revertedAt(revertedAt: JsonField<OffsetDateTime>) = apply {
@@ -261,8 +290,16 @@ private constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the set of events to deprecate
          */
-        fun deprecationFilter(deprecationFilter: String) =
-            deprecationFilter(JsonField.of(deprecationFilter))
+        fun deprecationFilter(deprecationFilter: String?) =
+            deprecationFilter(JsonField.ofNullable(deprecationFilter))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: Optional<String>) =
+            deprecationFilter(deprecationFilter.orElse(null))
 
         /**
          * A boolean
@@ -294,15 +331,15 @@ private constructor(
 
         fun build(): EventBackfillListResponse =
             EventBackfillListResponse(
-                id,
-                closeTime,
-                createdAt,
-                customerId,
-                eventsIngested,
-                revertedAt,
-                status,
-                timeframeEnd,
-                timeframeStart,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(closeTime) { "`closeTime` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(customerId) { "`customerId` is required but was not set" },
+                checkNotNull(eventsIngested) { "`eventsIngested` is required but was not set" },
+                checkNotNull(revertedAt) { "`revertedAt` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                 deprecationFilter,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertParams.kt
index e31bcd63..7869ed74 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertParams.kt
@@ -10,6 +10,14 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Reverting a backfill undoes all the effects of closing the backfill. If the backfill is
+ * reflected, the status will transition to `pending_revert` while the effects of the backfill are
+ * undone. Once all effects are undone, the backfill will transition to `reverted`.
+ *
+ * If a backfill is reverted before its closed, no usage will be updated as a result of the backfill
+ * and it will immediately transition to `reverted`.
+ */
 class EventBackfillRevertParams
 constructor(
     private val backfillId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertResponse.kt
index 40e14a1c..9b92704f 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventBackfillRevertResponse.kt
@@ -96,40 +96,54 @@ private constructor(
     fun deprecationFilter(): Optional<String> =
         Optional.ofNullable(deprecationFilter.getNullable("deprecation_filter"))
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * If in the future, the time at which the backfill will automatically close. If in the past,
      * the time at which the backfill was closed.
      */
-    @JsonProperty("close_time") @ExcludeMissing fun _closeTime() = closeTime
+    @JsonProperty("close_time")
+    @ExcludeMissing
+    fun _closeTime(): JsonField<OffsetDateTime> = closeTime
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
      * backfill is scoped to all customers.
      */
-    @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+    @JsonProperty("customer_id") @ExcludeMissing fun _customerId(): JsonField<String> = customerId
 
     /** The number of events ingested in this backfill. */
-    @JsonProperty("events_ingested") @ExcludeMissing fun _eventsIngested() = eventsIngested
+    @JsonProperty("events_ingested")
+    @ExcludeMissing
+    fun _eventsIngested(): JsonField<Long> = eventsIngested
 
     /** The time at which this backfill was reverted. */
-    @JsonProperty("reverted_at") @ExcludeMissing fun _revertedAt() = revertedAt
+    @JsonProperty("reverted_at")
+    @ExcludeMissing
+    fun _revertedAt(): JsonField<OffsetDateTime> = revertedAt
 
     /** The status of the backfill. */
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+    @JsonProperty("timeframe_end")
+    @ExcludeMissing
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-    @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+    @JsonProperty("timeframe_start")
+    @ExcludeMissing
+    fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
     /**
      * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
      * used to filter the set of events to deprecate
      */
-    @JsonProperty("deprecation_filter") @ExcludeMissing fun _deprecationFilter() = deprecationFilter
+    @JsonProperty("deprecation_filter")
+    @ExcludeMissing
+    fun _deprecationFilter(): JsonField<String> = deprecationFilter
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -162,15 +176,15 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var closeTime: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customerId: JsonField<String> = JsonMissing.of()
-        private var eventsIngested: JsonField<Long> = JsonMissing.of()
-        private var revertedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var closeTime: JsonField<OffsetDateTime>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var customerId: JsonField<String>? = null
+        private var eventsIngested: JsonField<Long>? = null
+        private var revertedAt: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var timeframeEnd: JsonField<OffsetDateTime>? = null
+        private var timeframeStart: JsonField<OffsetDateTime>? = null
         private var deprecationFilter: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -197,7 +211,13 @@ private constructor(
          * If in the future, the time at which the backfill will automatically close. If in the
          * past, the time at which the backfill was closed.
          */
-        fun closeTime(closeTime: OffsetDateTime) = closeTime(JsonField.of(closeTime))
+        fun closeTime(closeTime: OffsetDateTime?) = closeTime(JsonField.ofNullable(closeTime))
+
+        /**
+         * If in the future, the time at which the backfill will automatically close. If in the
+         * past, the time at which the backfill was closed.
+         */
+        fun closeTime(closeTime: Optional<OffsetDateTime>) = closeTime(closeTime.orElse(null))
 
         /**
          * If in the future, the time at which the backfill will automatically close. If in the
@@ -213,7 +233,13 @@ private constructor(
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
          * backfill is scoped to all customers.
          */
-        fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+        fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+        /**
+         * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
+         * backfill is scoped to all customers.
+         */
+        fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
         /**
          * The Orb-generated ID of the customer to which this backfill is scoped. If `null`, this
@@ -230,7 +256,10 @@ private constructor(
         }
 
         /** The time at which this backfill was reverted. */
-        fun revertedAt(revertedAt: OffsetDateTime) = revertedAt(JsonField.of(revertedAt))
+        fun revertedAt(revertedAt: OffsetDateTime?) = revertedAt(JsonField.ofNullable(revertedAt))
+
+        /** The time at which this backfill was reverted. */
+        fun revertedAt(revertedAt: Optional<OffsetDateTime>) = revertedAt(revertedAt.orElse(null))
 
         /** The time at which this backfill was reverted. */
         fun revertedAt(revertedAt: JsonField<OffsetDateTime>) = apply {
@@ -261,8 +290,16 @@ private constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the set of events to deprecate
          */
-        fun deprecationFilter(deprecationFilter: String) =
-            deprecationFilter(JsonField.of(deprecationFilter))
+        fun deprecationFilter(deprecationFilter: String?) =
+            deprecationFilter(JsonField.ofNullable(deprecationFilter))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the set of events to deprecate
+         */
+        fun deprecationFilter(deprecationFilter: Optional<String>) =
+            deprecationFilter(deprecationFilter.orElse(null))
 
         /**
          * A boolean
@@ -294,15 +331,15 @@ private constructor(
 
         fun build(): EventBackfillRevertResponse =
             EventBackfillRevertResponse(
-                id,
-                closeTime,
-                createdAt,
-                customerId,
-                eventsIngested,
-                revertedAt,
-                status,
-                timeframeEnd,
-                timeframeStart,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(closeTime) { "`closeTime` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(customerId) { "`customerId` is required but was not set" },
+                checkNotNull(eventsIngested) { "`eventsIngested` is required but was not set" },
+                checkNotNull(revertedAt) { "`revertedAt` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                 deprecationFilter,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateParams.kt
index 03248703..4649dfaa 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateParams.kt
@@ -10,6 +10,40 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to deprecate a single usage event with a given `event_id`. `event_id`
+ * refers to the `idempotency_key` passed in during ingestion.
+ *
+ * This endpoint will mark the existing event as ignored. Note that if you attempt to re-ingest an
+ * event with the same `event_id` as a deprecated event, Orb will return an error.
+ *
+ * This is a powerful and audit-safe mechanism to retroactively deprecate a single event in cases
+ * where you need to:
+ * - no longer bill for an event that was improperly reported
+ * - no longer bill for an event based on the result of an external API call (e.g. call to a payment
+ *   gateway failed and the user should not be billed)
+ *
+ * If you want to only change specific properties of an event, but keep the event as part of the
+ * billing calculation, use the [Amend event](amend-event) endpoint instead.
+ *
+ * This API is always audit-safe. The process will still retain the deprecated event, though it will
+ * be ignored for billing calculations. For auditing and data fidelity purposes, Orb never
+ * overwrites or permanently deletes ingested usage data.
+ *
+ * ## Request validation
+ * - Orb does not accept an `idempotency_key` with the event in this endpoint, since this request is
+ *   by design idempotent. On retryable errors, you should retry the request and assume the
+ *   deprecation operation has not succeeded until receipt of a 2xx.
+ * - The event's `timestamp` must fall within the customer's current subscription's billing period,
+ *   or within the grace period of the customer's current subscription's previous billing period.
+ *   Orb does not allow deprecating events for billing periods that have already invoiced customers.
+ * - The `customer_id` or the `external_customer_id` of the original event ingestion request must
+ *   identify a Customer resource within Orb, even if this event was ingested during the initial
+ *   integration period. We do not allow deprecating events for customers not in the Orb system.
+ * - By default, no more than 100 events can be deprecated for a single customer in a 100 day
+ *   period. For higher volume updates, consider using the [event backfill](create-backfill)
+ *   endpoint.
+ */
 class EventDeprecateParams
 constructor(
     private val eventId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateResponse.kt
index 79456aaa..17997534 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventDeprecateResponse.kt
@@ -29,7 +29,7 @@ private constructor(
     fun deprecated(): String = deprecated.getRequired("deprecated")
 
     /** event_id of the deprecated event, if successfully updated */
-    @JsonProperty("deprecated") @ExcludeMissing fun _deprecated() = deprecated
+    @JsonProperty("deprecated") @ExcludeMissing fun _deprecated(): JsonField<String> = deprecated
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,7 +53,7 @@ private constructor(
 
     class Builder {
 
-        private var deprecated: JsonField<String> = JsonMissing.of()
+        private var deprecated: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -88,7 +88,10 @@ private constructor(
         }
 
         fun build(): EventDeprecateResponse =
-            EventDeprecateResponse(deprecated, additionalProperties.toImmutable())
+            EventDeprecateResponse(
+                checkNotNull(deprecated) { "`deprecated` is required but was not set" },
+                additionalProperties.toImmutable()
+            )
     }
 
     override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestParams.kt
index 833c590a..b2bceb0e 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,192 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * Orb's event ingestion model and API is designed around two core principles:
+ * 1. **Data fidelity**: The accuracy of your billing model depends on a robust foundation of
+ *    events. Orb's API protocol encourages usage patterns that ensure that your data is
+ *    consistently complete and correct.
+ * 2. **Fast integration**: Sending events into Orb requires no tedious setup steps or explicit
+ *    field schema for your event shape, making it instant to start streaming in usage in real-time.
+ *
+ * ## Event shape
+ *
+ * Events are the starting point for all usage calculations in the system, and are simple at their
+ * core:
+ * ```ts
+ * {
+ *   // customer_id and external_customer_id are used to
+ *   // attribute usage to a given Customer. Exactly one of these
+ *   // should be specified in a given ingestion event.
+ *
+ *   // `customer_id` is the Orb generated identifier for the Customer,
+ *   // which is returned from the Create customer API call.
+ *   customer_id: string,
+ *
+ *   // external_customer_id is an alternate identifier which is associated
+ *   // with a Customer at creation time. This is treated as an alias for
+ *   // customer_id, and is usually set to an identifier native to your system.
+ *   external_customer_id: string,
+ *
+ *   // A string name identifying the event, usually a usage
+ *   // action. By convention, this should not contain any whitespace.
+ *   event_name: string,
+ *
+ *   // An ISO 8601 format date with no timezone offset.
+ *   // This should represent the time that usage occurred
+ *   // and is important to attribute usage to a given
+ *   // billing period. See the notes below on determining the timestamp.
+ *   // e.g. 2020-12-09T16:09:53Z
+ *   timestamp: string,
+ *
+ *   // A unique value, generated by the client, that is
+ *   // used to de-duplicate events.
+ *   // Exactly one event with a given
+ *   // idempotency key will be ingested, which allows for
+ *   // safe request retries.
+ *   idempotency_key: string
+ *
+ *   // Optional custom metadata to attach to the event.
+ *   // This might include a numeric value used for aggregation,
+ *   // or a string/boolean value used for filtering.
+ *   // The schema of this dictionary need not be pre-declared, and
+ *   // properties can be added at any time.
+ *   properties: {
+ *     [key: string]?: string | number | boolean,
+ *   },
+ * }
+ * ```
+ *
+ * ## Required fields
+ *
+ * Because events streamed to Orb are meant to be as flexible as possible, there are only a few
+ * required fields in every event.
+ * - We recommend that `idempotency_key` are unique strings that you generated with V4 UUIDs, but
+ *   only require that they uniquely identify an event (i.e. don’t collide).
+ * - The `timestamp` field in the event body will be used to determine which billable period a given
+ *   event falls into. For example, with a monthly billing cycle starting from the first of
+ *   December, Orb will calculate metrics based on events that fall into the range `12-01 00:00:00
+ *   <= timestamp < 01-01 00:00:00`.
+ *
+ * ## Logging metadata
+ *
+ * Orb allows tagging events with metadata using a flexible properties dictionary. Since Orb does
+ * not enforce a rigid schema for this field-set, key-value pairs can be added dynamically as your
+ * events evolve.
+ *
+ * This dictionary can be helpful for a wide variety of use cases:
+ * - Numeric properties on events like `compute_time_ms` can later be inputs to our flexible query
+ *   engine to determine usage.
+ * - Logging a region or cluster with each event can help you provide customers more granular
+ *   visibility into their usage.
+ *
+ * We encourage logging this metadata with an eye towards future use cases to ensure full coverage
+ * for historical data. The datatype of the value in the properties dictionary is important for
+ * metric creation from an event source. Values that you wish to numerically aggregate should be of
+ * numeric type in the event.
+ *
+ * ## Determining event timestamp
+ *
+ * For cases where usage is being reported in real time as it is occurring, timestamp should
+ * correspond to the time that usage occurred.
+ *
+ * In cases where usage is reported in aggregate for a historical timeframe at a regular interval,
+ * we recommend setting the event `timestamp` to the midpoint of the interval. As an example, if you
+ * have an hourly reporter that sends data once an hour for the previous hour of usage, setting the
+ * `timestamp` to the half-hour mark will ensure that the usage is counted within the correct
+ * period.
+ *
+ * Note that other time-related fields (e.g. time elapsed) can be added to the properties dictionary
+ * as necessary.
+ *
+ * In cases where usage is reported in aggregate for a historical timeframe, the timestamp must be
+ * within the grace period set for your account. Events with `timestamp < current_time -
+ * grace_period` will not be accepted as a valid event, and will throw validation errors. Enforcing
+ * the grace period enables Orb to accurately map usage to the correct billing cycle and ensure that
+ * all usage is billed for in the corresponding billing period.
+ *
+ * In general, Orb does not expect events with future dated timestamps. In cases where the timestamp
+ * is at least 24 hours ahead of the current time, the event will not be accepted as a valid event,
+ * and will throw validation errors.
+ *
+ * ## Event validation
+ *
+ * Orb’s validation ensures that you recognize errors in your events as quickly as possible, and the
+ * API provides informative error messages to help you fix problems quickly.
+ *
+ * We validate the following:
+ * - Exactly one of `customer_id` and `external_customer_id` should be specified.
+ * - If the `customer_id` is specified, the customer in Orb must exist.
+ * - If the `external_customer_id` is specified, the customer in Orb does not need to exist. Events
+ *   will be attributed to any future customers with the `external_customer_id` on subscription
+ *   creation.
+ * - `timestamp` must conform to ISO 8601 and represent a timestamp at most 1 hour in the future.
+ *   This timestamp should be sent in UTC timezone (no timezone offset).
+ *
+ * ## Idempotency and retry semantics
+ *
+ * Orb's idempotency guarantees allow you to implement safe retry logic in the event of network or
+ * machine failures, ensuring data fidelity. Each event in the request payload is associated with an
+ * idempotency key, and Orb guarantees that a single idempotency key will be successfully ingested
+ * at most once. Note that when Orb encounters events with duplicate idempotency keys and differing
+ * event bodies in a batch of events, the entire batch will be rejected.
+ * - Successful responses return a 200 HTTP status code. The response contains information about
+ *   previously processed events.
+ * - Requests that return a `4xx` HTTP status code indicate a payload error and contain at least one
+ *   event with a validation failure. An event with a validation failure can be re-sent to the
+ *   ingestion endpoint (after the payload is fixed) with the original idempotency key since that
+ *   key is not marked as processed.
+ * - Requests that return a `5xx` HTTP status code indicate a server-side failure. These requests
+ *   should be retried in their entirety.
+ *
+ * ## API usage and limits
+ *
+ * The ingestion API is designed made for real-time streaming ingestion and architected for high
+ * throughput. Even if events are later deemed unnecessary or filtered out, we encourage you to log
+ * them to Orb if they may be relevant to billing calculations in the future.
+ *
+ * To take advantage of the real-time features of the Orb platform and avoid any chance of dropped
+ * events by producers, we recommend reporting events to Orb frequently. Optionally, events can also
+ * be briefly aggregated at the source, as this API accepts an array of event bodies.
+ *
+ * Orb does not currently enforce a hard rate-limit for API usage or a maximum request payload size,
+ * but please give us a heads up if you’re changing either of these factors by an order of magnitude
+ * from initial setup.
+ *
+ * ## Testing in debug mode
+ *
+ * The ingestion API supports a debug mode, which returns additional verbose output to indicate
+ * which event idempotency keys were newly ingested or duplicates from previous requests. To enable
+ * this mode, mark `debug=true` as a query parameter.
+ *
+ * If `debug=true` is not specified, the response will only contain `validation_failed`. Orb will
+ * still honor the idempotency guarantees set
+ * [here](../guides/events-and-metrics/event-ingestion#event-volume-and-concurrency) in all cases.
+ *
+ * We strongly recommend that you only use debug mode as part of testing your initial Orb
+ * integration. Once you're ready to switch to production, disable debug mode to take advantage of
+ * improved performance and maximal throughput.
+ *
+ * #### Example: ingestion response with `debug=true`
+ *
+ * ```json
+ * {
+ *   "debug": {
+ *     "duplicate": [],
+ *     "ingested": ["B7E83HDMfJPAunXW", "SJs5DQJ3TnwSqEZE", "8SivfDsNKwCeAXim"]
+ *   },
+ *   "validation_failed": []
+ * }
+ * ```
+ *
+ * #### Example: ingestion response with `debug=false`
+ *
+ * ```json
+ * {
+ *   "validation_failed": []
+ * }
+ * ```
+ */
 class EventIngestParams
 constructor(
     private val backfillId: String?,
@@ -37,12 +225,14 @@ constructor(
 
     fun events(): List<Event> = body.events()
 
+    fun _events(): JsonField<List<Event>> = body._events()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): EventIngestBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -60,17 +250,30 @@ constructor(
     class EventIngestBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("events") private val events: List<Event>,
+        @JsonProperty("events")
+        @ExcludeMissing
+        private val events: JsonField<List<Event>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("events") fun events(): List<Event> = events
+        fun events(): List<Event> = events.getRequired("events")
+
+        @JsonProperty("events") @ExcludeMissing fun _events(): JsonField<List<Event>> = events
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): EventIngestBody = apply {
+            if (!validated) {
+                events().forEach { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -80,19 +283,32 @@ constructor(
 
         class Builder {
 
-            private var events: MutableList<Event>? = null
+            private var events: JsonField<MutableList<Event>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(eventIngestBody: EventIngestBody) = apply {
-                events = eventIngestBody.events.toMutableList()
+                events = eventIngestBody.events.map { it.toMutableList() }
                 additionalProperties = eventIngestBody.additionalProperties.toMutableMap()
             }
 
-            fun events(events: List<Event>) = apply { this.events = events.toMutableList() }
+            fun events(events: List<Event>) = events(JsonField.of(events))
+
+            fun events(events: JsonField<List<Event>>) = apply {
+                this.events = events.map { it.toMutableList() }
+            }
 
             fun addEvent(event: Event) = apply {
-                events = (events ?: mutableListOf()).apply { add(event) }
+                events =
+                    (events ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(event)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -116,7 +332,8 @@ constructor(
 
             fun build(): EventIngestBody =
                 EventIngestBody(
-                    checkNotNull(events) { "`events` is required but was not set" }.toImmutable(),
+                    checkNotNull(events) { "`events` is required but was not set" }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable()
                 )
         }
@@ -188,8 +405,29 @@ constructor(
 
         fun events(events: List<Event>) = apply { body.events(events) }
 
+        fun events(events: JsonField<List<Event>>) = apply { body.events(events) }
+
         fun addEvent(event: Event) = apply { body.addEvent(event) }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -288,25 +526,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): EventIngestParams =
             EventIngestParams(
                 backfillId,
@@ -321,51 +540,107 @@ constructor(
     class Event
     @JsonCreator
     private constructor(
-        @JsonProperty("event_name") private val eventName: String,
-        @JsonProperty("idempotency_key") private val idempotencyKey: String,
-        @JsonProperty("properties") private val properties: JsonValue,
-        @JsonProperty("timestamp") private val timestamp: OffsetDateTime,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
+        @JsonProperty("event_name")
+        @ExcludeMissing
+        private val eventName: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("idempotency_key")
+        @ExcludeMissing
+        private val idempotencyKey: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("properties")
+        @ExcludeMissing
+        private val properties: JsonValue = JsonMissing.of(),
+        @JsonProperty("timestamp")
+        @ExcludeMissing
+        private val timestamp: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** A name to meaningfully identify the action or event type. */
-        @JsonProperty("event_name") fun eventName(): String = eventName
+        fun eventName(): String = eventName.getRequired("event_name")
 
         /**
          * A unique value, generated by the client, that is used to de-duplicate events. Exactly one
          * event with a given idempotency key will be ingested, which allows for safe request
          * retries.
          */
-        @JsonProperty("idempotency_key") fun idempotencyKey(): String = idempotencyKey
+        fun idempotencyKey(): String = idempotencyKey.getRequired("idempotency_key")
 
         /**
          * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
          * strings. Nested dictionaries are disallowed.
          */
-        @JsonProperty("properties") fun properties(): JsonValue = properties
+        @JsonProperty("properties") @ExcludeMissing fun _properties(): JsonValue = properties
+
+        /**
+         * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
+         * time that usage was recorded, and is particularly important to attribute usage to a given
+         * billing period.
+         */
+        fun timestamp(): OffsetDateTime = timestamp.getRequired("timestamp")
+
+        /** The Orb Customer identifier */
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /** An alias for the Orb customer, whose mapping is specified when creating the customer */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /** A name to meaningfully identify the action or event type. */
+        @JsonProperty("event_name") @ExcludeMissing fun _eventName(): JsonField<String> = eventName
+
+        /**
+         * A unique value, generated by the client, that is used to de-duplicate events. Exactly one
+         * event with a given idempotency key will be ingested, which allows for safe request
+         * retries.
+         */
+        @JsonProperty("idempotency_key")
+        @ExcludeMissing
+        fun _idempotencyKey(): JsonField<String> = idempotencyKey
 
         /**
          * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
          * time that usage was recorded, and is particularly important to attribute usage to a given
          * billing period.
          */
-        @JsonProperty("timestamp") fun timestamp(): OffsetDateTime = timestamp
+        @JsonProperty("timestamp")
+        @ExcludeMissing
+        fun _timestamp(): JsonField<OffsetDateTime> = timestamp
 
         /** The Orb Customer identifier */
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /** An alias for the Orb customer, whose mapping is specified when creating the customer */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Event = apply {
+            if (!validated) {
+                eventName()
+                idempotencyKey()
+                timestamp()
+                customerId()
+                externalCustomerId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -375,12 +650,12 @@ constructor(
 
         class Builder {
 
-            private var eventName: String? = null
-            private var idempotencyKey: String? = null
+            private var eventName: JsonField<String>? = null
+            private var idempotencyKey: JsonField<String>? = null
             private var properties: JsonValue? = null
-            private var timestamp: OffsetDateTime? = null
-            private var customerId: String? = null
-            private var externalCustomerId: String? = null
+            private var timestamp: JsonField<OffsetDateTime>? = null
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -395,14 +670,25 @@ constructor(
             }
 
             /** A name to meaningfully identify the action or event type. */
-            fun eventName(eventName: String) = apply { this.eventName = eventName }
+            fun eventName(eventName: String) = eventName(JsonField.of(eventName))
+
+            /** A name to meaningfully identify the action or event type. */
+            fun eventName(eventName: JsonField<String>) = apply { this.eventName = eventName }
+
+            /**
+             * A unique value, generated by the client, that is used to de-duplicate events. Exactly
+             * one event with a given idempotency key will be ingested, which allows for safe
+             * request retries.
+             */
+            fun idempotencyKey(idempotencyKey: String) =
+                idempotencyKey(JsonField.of(idempotencyKey))
 
             /**
              * A unique value, generated by the client, that is used to de-duplicate events. Exactly
              * one event with a given idempotency key will be ingested, which allows for safe
              * request retries.
              */
-            fun idempotencyKey(idempotencyKey: String) = apply {
+            fun idempotencyKey(idempotencyKey: JsonField<String>) = apply {
                 this.idempotencyKey = idempotencyKey
             }
 
@@ -417,20 +703,31 @@ constructor(
              * time that usage was recorded, and is particularly important to attribute usage to a
              * given billing period.
              */
-            fun timestamp(timestamp: OffsetDateTime) = apply { this.timestamp = timestamp }
+            fun timestamp(timestamp: OffsetDateTime) = timestamp(JsonField.of(timestamp))
+
+            /**
+             * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
+             * time that usage was recorded, and is particularly important to attribute usage to a
+             * given billing period.
+             */
+            fun timestamp(timestamp: JsonField<OffsetDateTime>) = apply {
+                this.timestamp = timestamp
+            }
 
             /** The Orb Customer identifier */
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             /** The Orb Customer identifier */
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            /** The Orb Customer identifier */
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
@@ -438,6 +735,13 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * An alias for the Orb customer, whose mapping is specified when creating the customer
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestResponse.kt
index bcf9737a..dea4eb2a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventIngestResponse.kt
@@ -44,13 +44,15 @@ private constructor(
      * Contains all failing validation events. In the case of a 200, this array will always be
      * empty. This field will always be present.
      */
-    @JsonProperty("validation_failed") @ExcludeMissing fun _validationFailed() = validationFailed
+    @JsonProperty("validation_failed")
+    @ExcludeMissing
+    fun _validationFailed(): JsonField<List<ValidationFailed>> = validationFailed
 
     /**
      * Optional debug information (only present when debug=true is passed to the endpoint). Contains
      * ingested and duplicate event idempotency keys.
      */
-    @JsonProperty("debug") @ExcludeMissing fun _debug() = debug
+    @JsonProperty("debug") @ExcludeMissing fun _debug(): JsonField<Debug> = debug
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -75,13 +77,13 @@ private constructor(
 
     class Builder {
 
-        private var validationFailed: JsonField<List<ValidationFailed>> = JsonMissing.of()
+        private var validationFailed: JsonField<MutableList<ValidationFailed>>? = null
         private var debug: JsonField<Debug> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(eventIngestResponse: EventIngestResponse) = apply {
-            validationFailed = eventIngestResponse.validationFailed
+            validationFailed = eventIngestResponse.validationFailed.map { it.toMutableList() }
             debug = eventIngestResponse.debug
             additionalProperties = eventIngestResponse.additionalProperties.toMutableMap()
         }
@@ -98,14 +100,37 @@ private constructor(
          * empty. This field will always be present.
          */
         fun validationFailed(validationFailed: JsonField<List<ValidationFailed>>) = apply {
-            this.validationFailed = validationFailed
+            this.validationFailed = validationFailed.map { it.toMutableList() }
+        }
+
+        /**
+         * Contains all failing validation events. In the case of a 200, this array will always be
+         * empty. This field will always be present.
+         */
+        fun addValidationFailed(validationFailed: ValidationFailed) = apply {
+            this.validationFailed =
+                (this.validationFailed ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(validationFailed)
+                }
         }
 
         /**
          * Optional debug information (only present when debug=true is passed to the endpoint).
          * Contains ingested and duplicate event idempotency keys.
          */
-        fun debug(debug: Debug) = debug(JsonField.of(debug))
+        fun debug(debug: Debug?) = debug(JsonField.ofNullable(debug))
+
+        /**
+         * Optional debug information (only present when debug=true is passed to the endpoint).
+         * Contains ingested and duplicate event idempotency keys.
+         */
+        fun debug(debug: Optional<Debug>) = debug(debug.orElse(null))
 
         /**
          * Optional debug information (only present when debug=true is passed to the endpoint).
@@ -134,7 +159,8 @@ private constructor(
 
         fun build(): EventIngestResponse =
             EventIngestResponse(
-                validationFailed.map { it.toImmutable() },
+                checkNotNull(validationFailed) { "`validationFailed` is required but was not set" }
+                    .map { it.toImmutable() },
                 debug,
                 additionalProperties.toImmutable(),
             )
@@ -161,12 +187,14 @@ private constructor(
         fun validationErrors(): List<String> = validationErrors.getRequired("validation_errors")
 
         /** The passed idempotency_key corresponding to the validation_errors */
-        @JsonProperty("idempotency_key") @ExcludeMissing fun _idempotencyKey() = idempotencyKey
+        @JsonProperty("idempotency_key")
+        @ExcludeMissing
+        fun _idempotencyKey(): JsonField<String> = idempotencyKey
 
         /** An array of strings corresponding to validation failures for this idempotency_key. */
         @JsonProperty("validation_errors")
         @ExcludeMissing
-        fun _validationErrors() = validationErrors
+        fun _validationErrors(): JsonField<List<String>> = validationErrors
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -191,14 +219,14 @@ private constructor(
 
         class Builder {
 
-            private var idempotencyKey: JsonField<String> = JsonMissing.of()
-            private var validationErrors: JsonField<List<String>> = JsonMissing.of()
+            private var idempotencyKey: JsonField<String>? = null
+            private var validationErrors: JsonField<MutableList<String>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(validationFailed: ValidationFailed) = apply {
                 idempotencyKey = validationFailed.idempotencyKey
-                validationErrors = validationFailed.validationErrors
+                validationErrors = validationFailed.validationErrors.map { it.toMutableList() }
                 additionalProperties = validationFailed.additionalProperties.toMutableMap()
             }
 
@@ -221,7 +249,23 @@ private constructor(
              * An array of strings corresponding to validation failures for this idempotency_key.
              */
             fun validationErrors(validationErrors: JsonField<List<String>>) = apply {
-                this.validationErrors = validationErrors
+                this.validationErrors = validationErrors.map { it.toMutableList() }
+            }
+
+            /**
+             * An array of strings corresponding to validation failures for this idempotency_key.
+             */
+            fun addValidationError(validationError: String) = apply {
+                validationErrors =
+                    (validationErrors ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(validationError)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -245,8 +289,11 @@ private constructor(
 
             fun build(): ValidationFailed =
                 ValidationFailed(
-                    idempotencyKey,
-                    validationErrors.map { it.toImmutable() },
+                    checkNotNull(idempotencyKey) { "`idempotencyKey` is required but was not set" },
+                    checkNotNull(validationErrors) {
+                            "`validationErrors` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -291,9 +338,13 @@ private constructor(
 
         fun ingested(): List<String> = ingested.getRequired("ingested")
 
-        @JsonProperty("duplicate") @ExcludeMissing fun _duplicate() = duplicate
+        @JsonProperty("duplicate")
+        @ExcludeMissing
+        fun _duplicate(): JsonField<List<String>> = duplicate
 
-        @JsonProperty("ingested") @ExcludeMissing fun _ingested() = ingested
+        @JsonProperty("ingested")
+        @ExcludeMissing
+        fun _ingested(): JsonField<List<String>> = ingested
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -318,24 +369,54 @@ private constructor(
 
         class Builder {
 
-            private var duplicate: JsonField<List<String>> = JsonMissing.of()
-            private var ingested: JsonField<List<String>> = JsonMissing.of()
+            private var duplicate: JsonField<MutableList<String>>? = null
+            private var ingested: JsonField<MutableList<String>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(debug: Debug) = apply {
-                duplicate = debug.duplicate
-                ingested = debug.ingested
+                duplicate = debug.duplicate.map { it.toMutableList() }
+                ingested = debug.ingested.map { it.toMutableList() }
                 additionalProperties = debug.additionalProperties.toMutableMap()
             }
 
             fun duplicate(duplicate: List<String>) = duplicate(JsonField.of(duplicate))
 
-            fun duplicate(duplicate: JsonField<List<String>>) = apply { this.duplicate = duplicate }
+            fun duplicate(duplicate: JsonField<List<String>>) = apply {
+                this.duplicate = duplicate.map { it.toMutableList() }
+            }
+
+            fun addDuplicate(duplicate: String) = apply {
+                this.duplicate =
+                    (this.duplicate ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(duplicate)
+                    }
+            }
 
             fun ingested(ingested: List<String>) = ingested(JsonField.of(ingested))
 
-            fun ingested(ingested: JsonField<List<String>>) = apply { this.ingested = ingested }
+            fun ingested(ingested: JsonField<List<String>>) = apply {
+                this.ingested = ingested.map { it.toMutableList() }
+            }
+
+            fun addIngested(ingested: String) = apply {
+                this.ingested =
+                    (this.ingested ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(ingested)
+                    }
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -358,8 +439,10 @@ private constructor(
 
             fun build(): Debug =
                 Debug(
-                    duplicate.map { it.toImmutable() },
-                    ingested.map { it.toImmutable() },
+                    checkNotNull(duplicate) { "`duplicate` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(ingested) { "`ingested` is required but was not set" }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchParams.kt
index f2bce686..2b713646 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,20 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a filtered set of events for an account in a
+ * [paginated list format](../reference/pagination).
+ *
+ * Note that this is a `POST` endpoint rather than a `GET` endpoint because it employs a JSON body
+ * for search criteria rather than query parameters, allowing for a more flexible search syntax.
+ *
+ * Note that a search criteria _must_ be specified. Currently, Orb supports the following criteria:
+ * - `event_ids`: This is an explicit array of IDs to filter by. Note that an event's ID is the
+ *   `idempotency_key` that was originally used for ingestion.
+ *
+ * By default, Orb will not throw a `404` if no events matched, Orb will return an empty array for
+ * `data` instead.
+ */
 class EventSearchParams
 constructor(
     private val body: EventSearchBody,
@@ -43,12 +59,31 @@ constructor(
      */
     fun timeframeStart(): Optional<OffsetDateTime> = body.timeframeStart()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * This is an explicit array of IDs to filter by. Note that an event's ID is the idempotency_key
+     * that was originally used for ingestion, and this only supports events that have not been
+     * amended. Values in this array will be treated case sensitively.
+     */
+    fun _eventIds(): JsonField<List<String>> = body._eventIds()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * The end of the timeframe, exclusive, in which to search events. If not specified, the current
+     * time is used.
+     */
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = body._timeframeEnd()
+
+    /**
+     * The start of the timeframe, inclusive, in which to search events. If not specified, the one
+     * week ago is used.
+     */
+    fun _timeframeStart(): JsonField<OffsetDateTime> = body._timeframeStart()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): EventSearchBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -59,9 +94,15 @@ constructor(
     class EventSearchBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("event_ids") private val eventIds: List<String>,
-        @JsonProperty("timeframe_end") private val timeframeEnd: OffsetDateTime?,
-        @JsonProperty("timeframe_start") private val timeframeStart: OffsetDateTime?,
+        @JsonProperty("event_ids")
+        @ExcludeMissing
+        private val eventIds: JsonField<List<String>> = JsonMissing.of(),
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        private val timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        private val timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -71,26 +112,62 @@ constructor(
          * idempotency_key that was originally used for ingestion, and this only supports events
          * that have not been amended. Values in this array will be treated case sensitively.
          */
-        @JsonProperty("event_ids") fun eventIds(): List<String> = eventIds
+        fun eventIds(): List<String> = eventIds.getRequired("event_ids")
+
+        /**
+         * The end of the timeframe, exclusive, in which to search events. If not specified, the
+         * current time is used.
+         */
+        fun timeframeEnd(): Optional<OffsetDateTime> =
+            Optional.ofNullable(timeframeEnd.getNullable("timeframe_end"))
+
+        /**
+         * The start of the timeframe, inclusive, in which to search events. If not specified, the
+         * one week ago is used.
+         */
+        fun timeframeStart(): Optional<OffsetDateTime> =
+            Optional.ofNullable(timeframeStart.getNullable("timeframe_start"))
+
+        /**
+         * This is an explicit array of IDs to filter by. Note that an event's ID is the
+         * idempotency_key that was originally used for ingestion, and this only supports events
+         * that have not been amended. Values in this array will be treated case sensitively.
+         */
+        @JsonProperty("event_ids")
+        @ExcludeMissing
+        fun _eventIds(): JsonField<List<String>> = eventIds
 
         /**
          * The end of the timeframe, exclusive, in which to search events. If not specified, the
          * current time is used.
          */
         @JsonProperty("timeframe_end")
-        fun timeframeEnd(): Optional<OffsetDateTime> = Optional.ofNullable(timeframeEnd)
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
         /**
          * The start of the timeframe, inclusive, in which to search events. If not specified, the
          * one week ago is used.
          */
         @JsonProperty("timeframe_start")
-        fun timeframeStart(): Optional<OffsetDateTime> = Optional.ofNullable(timeframeStart)
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): EventSearchBody = apply {
+            if (!validated) {
+                eventIds()
+                timeframeEnd()
+                timeframeStart()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -100,14 +177,14 @@ constructor(
 
         class Builder {
 
-            private var eventIds: MutableList<String>? = null
-            private var timeframeEnd: OffsetDateTime? = null
-            private var timeframeStart: OffsetDateTime? = null
+            private var eventIds: JsonField<MutableList<String>>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(eventSearchBody: EventSearchBody) = apply {
-                eventIds = eventSearchBody.eventIds.toMutableList()
+                eventIds = eventSearchBody.eventIds.map { it.toMutableList() }
                 timeframeEnd = eventSearchBody.timeframeEnd
                 timeframeStart = eventSearchBody.timeframeStart
                 additionalProperties = eventSearchBody.additionalProperties.toMutableMap()
@@ -118,8 +195,15 @@ constructor(
              * idempotency_key that was originally used for ingestion, and this only supports events
              * that have not been amended. Values in this array will be treated case sensitively.
              */
-            fun eventIds(eventIds: List<String>) = apply {
-                this.eventIds = eventIds.toMutableList()
+            fun eventIds(eventIds: List<String>) = eventIds(JsonField.of(eventIds))
+
+            /**
+             * This is an explicit array of IDs to filter by. Note that an event's ID is the
+             * idempotency_key that was originally used for ingestion, and this only supports events
+             * that have not been amended. Values in this array will be treated case sensitively.
+             */
+            fun eventIds(eventIds: JsonField<List<String>>) = apply {
+                this.eventIds = eventIds.map { it.toMutableList() }
             }
 
             /**
@@ -128,16 +212,24 @@ constructor(
              * that have not been amended. Values in this array will be treated case sensitively.
              */
             fun addEventId(eventId: String) = apply {
-                eventIds = (eventIds ?: mutableListOf()).apply { add(eventId) }
+                eventIds =
+                    (eventIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(eventId)
+                    }
             }
 
             /**
              * The end of the timeframe, exclusive, in which to search events. If not specified, the
              * current time is used.
              */
-            fun timeframeEnd(timeframeEnd: OffsetDateTime?) = apply {
-                this.timeframeEnd = timeframeEnd
-            }
+            fun timeframeEnd(timeframeEnd: OffsetDateTime?) =
+                timeframeEnd(JsonField.ofNullable(timeframeEnd))
 
             /**
              * The end of the timeframe, exclusive, in which to search events. If not specified, the
@@ -146,13 +238,20 @@ constructor(
             fun timeframeEnd(timeframeEnd: Optional<OffsetDateTime>) =
                 timeframeEnd(timeframeEnd.orElse(null))
 
+            /**
+             * The end of the timeframe, exclusive, in which to search events. If not specified, the
+             * current time is used.
+             */
+            fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
+                this.timeframeEnd = timeframeEnd
+            }
+
             /**
              * The start of the timeframe, inclusive, in which to search events. If not specified,
              * the one week ago is used.
              */
-            fun timeframeStart(timeframeStart: OffsetDateTime?) = apply {
-                this.timeframeStart = timeframeStart
-            }
+            fun timeframeStart(timeframeStart: OffsetDateTime?) =
+                timeframeStart(JsonField.ofNullable(timeframeStart))
 
             /**
              * The start of the timeframe, inclusive, in which to search events. If not specified,
@@ -161,6 +260,14 @@ constructor(
             fun timeframeStart(timeframeStart: Optional<OffsetDateTime>) =
                 timeframeStart(timeframeStart.orElse(null))
 
+            /**
+             * The start of the timeframe, inclusive, in which to search events. If not specified,
+             * the one week ago is used.
+             */
+            fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
+                this.timeframeStart = timeframeStart
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -183,7 +290,7 @@ constructor(
             fun build(): EventSearchBody =
                 EventSearchBody(
                     checkNotNull(eventIds) { "`eventIds` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     timeframeEnd,
                     timeframeStart,
                     additionalProperties.toImmutable(),
@@ -236,6 +343,13 @@ constructor(
          */
         fun eventIds(eventIds: List<String>) = apply { body.eventIds(eventIds) }
 
+        /**
+         * This is an explicit array of IDs to filter by. Note that an event's ID is the
+         * idempotency_key that was originally used for ingestion, and this only supports events
+         * that have not been amended. Values in this array will be treated case sensitively.
+         */
+        fun eventIds(eventIds: JsonField<List<String>>) = apply { body.eventIds(eventIds) }
+
         /**
          * This is an explicit array of IDs to filter by. Note that an event's ID is the
          * idempotency_key that was originally used for ingestion, and this only supports events
@@ -256,6 +370,14 @@ constructor(
         fun timeframeEnd(timeframeEnd: Optional<OffsetDateTime>) =
             timeframeEnd(timeframeEnd.orElse(null))
 
+        /**
+         * The end of the timeframe, exclusive, in which to search events. If not specified, the
+         * current time is used.
+         */
+        fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
+            body.timeframeEnd(timeframeEnd)
+        }
+
         /**
          * The start of the timeframe, inclusive, in which to search events. If not specified, the
          * one week ago is used.
@@ -271,6 +393,33 @@ constructor(
         fun timeframeStart(timeframeStart: Optional<OffsetDateTime>) =
             timeframeStart(timeframeStart.orElse(null))
 
+        /**
+         * The start of the timeframe, inclusive, in which to search events. If not specified, the
+         * one week ago is used.
+         */
+        fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
+            body.timeframeStart(timeframeStart)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -369,25 +518,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): EventSearchParams =
             EventSearchParams(
                 body.build(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchResponse.kt
index 113b29b2..8eaf8bcd 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventSearchResponse.kt
@@ -29,7 +29,7 @@ private constructor(
 
     fun data(): List<Data> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,18 +53,33 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Data>> = JsonMissing.of()
+        private var data: JsonField<MutableList<Data>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(eventSearchResponse: EventSearchResponse) = apply {
-            data = eventSearchResponse.data
+            data = eventSearchResponse.data.map { it.toMutableList() }
             additionalProperties = eventSearchResponse.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Data>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Data>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Data) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -86,7 +101,11 @@ private constructor(
         }
 
         fun build(): EventSearchResponse =
-            EventSearchResponse(data.map { it.toImmutable() }, additionalProperties.toImmutable())
+            EventSearchResponse(
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
+                additionalProperties.toImmutable()
+            )
     }
 
     /**
@@ -142,6 +161,12 @@ private constructor(
         fun externalCustomerId(): Optional<String> =
             Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
+        /**
+         * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
+         * strings. Nested dictionaries are disallowed.
+         */
+        @JsonProperty("properties") @ExcludeMissing fun _properties(): JsonValue = properties
+
         /**
          * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
          * time that usage was recorded, and is particularly important to attribute usage to a given
@@ -154,34 +179,34 @@ private constructor(
          * event with a given idempotency key will be ingested, which allows for safe request
          * retries.
          */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The Orb Customer identifier */
-        @JsonProperty("customer_id") @ExcludeMissing fun _customerId() = customerId
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /** A boolean indicating whether the event is currently deprecated. */
-        @JsonProperty("deprecated") @ExcludeMissing fun _deprecated() = deprecated
+        @JsonProperty("deprecated")
+        @ExcludeMissing
+        fun _deprecated(): JsonField<Boolean> = deprecated
 
         /** A name to meaningfully identify the action or event type. */
-        @JsonProperty("event_name") @ExcludeMissing fun _eventName() = eventName
+        @JsonProperty("event_name") @ExcludeMissing fun _eventName(): JsonField<String> = eventName
 
         /** An alias for the Orb customer, whose mapping is specified when creating the customer */
         @JsonProperty("external_customer_id")
         @ExcludeMissing
-        fun _externalCustomerId() = externalCustomerId
-
-        /**
-         * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
-         * strings. Nested dictionaries are disallowed.
-         */
-        @JsonProperty("properties") @ExcludeMissing fun _properties() = properties
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
          * time that usage was recorded, and is particularly important to attribute usage to a given
          * billing period.
          */
-        @JsonProperty("timestamp") @ExcludeMissing fun _timestamp() = timestamp
+        @JsonProperty("timestamp")
+        @ExcludeMissing
+        fun _timestamp(): JsonField<OffsetDateTime> = timestamp
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -210,13 +235,13 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var customerId: JsonField<String> = JsonMissing.of()
-            private var deprecated: JsonField<Boolean> = JsonMissing.of()
-            private var eventName: JsonField<String> = JsonMissing.of()
-            private var externalCustomerId: JsonField<String> = JsonMissing.of()
-            private var properties: JsonValue = JsonMissing.of()
-            private var timestamp: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var customerId: JsonField<String>? = null
+            private var deprecated: JsonField<Boolean>? = null
+            private var eventName: JsonField<String>? = null
+            private var externalCustomerId: JsonField<String>? = null
+            private var properties: JsonValue? = null
+            private var timestamp: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -246,7 +271,10 @@ private constructor(
             fun id(id: JsonField<String>) = apply { this.id = id }
 
             /** The Orb Customer identifier */
-            fun customerId(customerId: String) = customerId(JsonField.of(customerId))
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
+
+            /** The Orb Customer identifier */
+            fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
             /** The Orb Customer identifier */
             fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
@@ -266,8 +294,14 @@ private constructor(
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
              */
-            fun externalCustomerId(externalCustomerId: String) =
-                externalCustomerId(JsonField.of(externalCustomerId))
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+            /**
+             * An alias for the Orb customer, whose mapping is specified when creating the customer
+             */
+            fun externalCustomerId(externalCustomerId: Optional<String>) =
+                externalCustomerId(externalCustomerId.orElse(null))
 
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
@@ -319,13 +353,15 @@ private constructor(
 
             fun build(): Data =
                 Data(
-                    id,
-                    customerId,
-                    deprecated,
-                    eventName,
-                    externalCustomerId,
-                    properties,
-                    timestamp,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(customerId) { "`customerId` is required but was not set" },
+                    checkNotNull(deprecated) { "`deprecated` is required but was not set" },
+                    checkNotNull(eventName) { "`eventName` is required but was not set" },
+                    checkNotNull(externalCustomerId) {
+                        "`externalCustomerId` is required but was not set"
+                    },
+                    checkNotNull(properties) { "`properties` is required but was not set" },
+                    checkNotNull(timestamp) { "`timestamp` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateParams.kt
index 7d877ef2..7e146df1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,45 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to amend a single usage event with a given `event_id`. `event_id` refers to
+ * the `idempotency_key` passed in during ingestion. The event will maintain its existing `event_id`
+ * after the amendment.
+ *
+ * This endpoint will mark the existing event as ignored, and Orb will only use the new event passed
+ * in the body of this request as the source of truth for that `event_id`. Note that a single event
+ * can be amended any number of times, so the same event can be overwritten in subsequent calls to
+ * this endpoint. Only a single event with a given `event_id` will be considered the source of truth
+ * at any given time.
+ *
+ * This is a powerful and audit-safe mechanism to retroactively update a single event in cases where
+ * you need to:
+ * - update an event with new metadata as you iterate on your pricing model
+ * - update an event based on the result of an external API call (e.g. call to a payment gateway
+ *   succeeded or failed)
+ *
+ * This amendment API is always audit-safe. The process will still retain the original event, though
+ * it will be ignored for billing calculations. For auditing and data fidelity purposes, Orb never
+ * overwrites or permanently deletes ingested usage data.
+ *
+ * ## Request validation
+ * - The `timestamp` of the new event must match the `timestamp` of the existing event already
+ *   ingested. As with ingestion, all timestamps must be sent in ISO8601 format with UTC timezone
+ *   offset.
+ * - The `customer_id` or `external_customer_id` of the new event must match the `customer_id` or
+ *   `external_customer_id` of the existing event already ingested. Exactly one of `customer_id` and
+ *   `external_customer_id` should be specified, and similar to ingestion, the ID must identify a
+ *   Customer resource within Orb. Unlike ingestion, for event amendment, we strictly enforce that
+ *   the Customer must be in the Orb system, even during the initial integration period. We do not
+ *   allow updating the `Customer` an event is associated with.
+ * - Orb does not accept an `idempotency_key` with the event in this endpoint, since this request is
+ *   by design idempotent. On retryable errors, you should retry the request and assume the
+ *   amendment operation has not succeeded until receipt of a 2xx.
+ * - The event's `timestamp` must fall within the customer's current subscription's billing period,
+ *   or within the grace period of the customer's current subscription's previous billing period.
+ * - By default, no more than 100 events can be amended for a single customer in a 100 day period.
+ *   For higher volume updates, consider using the [event backfill](create-backfill) endpoint.
+ */
 class EventUpdateParams
 constructor(
     private val eventId: String,
@@ -34,7 +75,7 @@ constructor(
      * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
      * strings. Nested dictionaries are disallowed.
      */
-    fun properties(): JsonValue = body.properties()
+    fun _properties(): JsonValue = body._properties()
 
     /**
      * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the time
@@ -49,12 +90,28 @@ constructor(
     /** An alias for the Orb customer, whose mapping is specified when creating the customer */
     fun externalCustomerId(): Optional<String> = body.externalCustomerId()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** A name to meaningfully identify the action or event type. */
+    fun _eventName(): JsonField<String> = body._eventName()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the time
+     * that usage was recorded, and is particularly important to attribute usage to a given billing
+     * period.
+     */
+    fun _timestamp(): JsonField<OffsetDateTime> = body._timestamp()
+
+    /** The Orb Customer identifier */
+    fun _customerId(): JsonField<String> = body._customerId()
+
+    /** An alias for the Orb customer, whose mapping is specified when creating the customer */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): EventUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -72,43 +129,87 @@ constructor(
     class EventUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("event_name") private val eventName: String,
-        @JsonProperty("properties") private val properties: JsonValue,
-        @JsonProperty("timestamp") private val timestamp: OffsetDateTime,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
+        @JsonProperty("event_name")
+        @ExcludeMissing
+        private val eventName: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("properties")
+        @ExcludeMissing
+        private val properties: JsonValue = JsonMissing.of(),
+        @JsonProperty("timestamp")
+        @ExcludeMissing
+        private val timestamp: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** A name to meaningfully identify the action or event type. */
-        @JsonProperty("event_name") fun eventName(): String = eventName
+        fun eventName(): String = eventName.getRequired("event_name")
 
         /**
          * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
          * strings. Nested dictionaries are disallowed.
          */
-        @JsonProperty("properties") fun properties(): JsonValue = properties
+        @JsonProperty("properties") @ExcludeMissing fun _properties(): JsonValue = properties
 
         /**
          * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
          * time that usage was recorded, and is particularly important to attribute usage to a given
          * billing period.
          */
-        @JsonProperty("timestamp") fun timestamp(): OffsetDateTime = timestamp
+        fun timestamp(): OffsetDateTime = timestamp.getRequired("timestamp")
+
+        /** The Orb Customer identifier */
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /** An alias for the Orb customer, whose mapping is specified when creating the customer */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /** A name to meaningfully identify the action or event type. */
+        @JsonProperty("event_name") @ExcludeMissing fun _eventName(): JsonField<String> = eventName
+
+        /**
+         * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
+         * time that usage was recorded, and is particularly important to attribute usage to a given
+         * billing period.
+         */
+        @JsonProperty("timestamp")
+        @ExcludeMissing
+        fun _timestamp(): JsonField<OffsetDateTime> = timestamp
 
         /** The Orb Customer identifier */
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /** An alias for the Orb customer, whose mapping is specified when creating the customer */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): EventUpdateBody = apply {
+            if (!validated) {
+                eventName()
+                timestamp()
+                customerId()
+                externalCustomerId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -118,11 +219,11 @@ constructor(
 
         class Builder {
 
-            private var eventName: String? = null
+            private var eventName: JsonField<String>? = null
             private var properties: JsonValue? = null
-            private var timestamp: OffsetDateTime? = null
-            private var customerId: String? = null
-            private var externalCustomerId: String? = null
+            private var timestamp: JsonField<OffsetDateTime>? = null
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -136,7 +237,10 @@ constructor(
             }
 
             /** A name to meaningfully identify the action or event type. */
-            fun eventName(eventName: String) = apply { this.eventName = eventName }
+            fun eventName(eventName: String) = eventName(JsonField.of(eventName))
+
+            /** A name to meaningfully identify the action or event type. */
+            fun eventName(eventName: JsonField<String>) = apply { this.eventName = eventName }
 
             /**
              * A dictionary of custom properties. Values in this dictionary must be numeric,
@@ -149,20 +253,31 @@ constructor(
              * time that usage was recorded, and is particularly important to attribute usage to a
              * given billing period.
              */
-            fun timestamp(timestamp: OffsetDateTime) = apply { this.timestamp = timestamp }
+            fun timestamp(timestamp: OffsetDateTime) = timestamp(JsonField.of(timestamp))
+
+            /**
+             * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
+             * time that usage was recorded, and is particularly important to attribute usage to a
+             * given billing period.
+             */
+            fun timestamp(timestamp: JsonField<OffsetDateTime>) = apply {
+                this.timestamp = timestamp
+            }
 
             /** The Orb Customer identifier */
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             /** The Orb Customer identifier */
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            /** The Orb Customer identifier */
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * An alias for the Orb customer, whose mapping is specified when creating the customer
@@ -170,6 +285,13 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * An alias for the Orb customer, whose mapping is specified when creating the customer
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -246,6 +368,9 @@ constructor(
         /** A name to meaningfully identify the action or event type. */
         fun eventName(eventName: String) = apply { body.eventName(eventName) }
 
+        /** A name to meaningfully identify the action or event type. */
+        fun eventName(eventName: JsonField<String>) = apply { body.eventName(eventName) }
+
         /**
          * A dictionary of custom properties. Values in this dictionary must be numeric, boolean, or
          * strings. Nested dictionaries are disallowed.
@@ -259,12 +384,22 @@ constructor(
          */
         fun timestamp(timestamp: OffsetDateTime) = apply { body.timestamp(timestamp) }
 
+        /**
+         * An ISO 8601 format date with no timezone offset (i.e. UTC). This should represent the
+         * time that usage was recorded, and is particularly important to attribute usage to a given
+         * billing period.
+         */
+        fun timestamp(timestamp: JsonField<OffsetDateTime>) = apply { body.timestamp(timestamp) }
+
         /** The Orb Customer identifier */
         fun customerId(customerId: String?) = apply { body.customerId(customerId) }
 
         /** The Orb Customer identifier */
         fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+        /** The Orb Customer identifier */
+        fun customerId(customerId: JsonField<String>) = apply { body.customerId(customerId) }
+
         /** An alias for the Orb customer, whose mapping is specified when creating the customer */
         fun externalCustomerId(externalCustomerId: String?) = apply {
             body.externalCustomerId(externalCustomerId)
@@ -274,6 +409,30 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /** An alias for the Orb customer, whose mapping is specified when creating the customer */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -372,25 +531,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): EventUpdateParams =
             EventUpdateParams(
                 checkNotNull(eventId) { "`eventId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateResponse.kt
index 3d3e7c94..9f3602f4 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventUpdateResponse.kt
@@ -29,7 +29,7 @@ private constructor(
     fun amended(): String = amended.getRequired("amended")
 
     /** event_id of the amended event, if successfully ingested */
-    @JsonProperty("amended") @ExcludeMissing fun _amended() = amended
+    @JsonProperty("amended") @ExcludeMissing fun _amended(): JsonField<String> = amended
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,7 +53,7 @@ private constructor(
 
     class Builder {
 
-        private var amended: JsonField<String> = JsonMissing.of()
+        private var amended: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -88,7 +88,10 @@ private constructor(
         }
 
         fun build(): EventUpdateResponse =
-            EventUpdateResponse(amended, additionalProperties.toImmutable())
+            EventUpdateResponse(
+                checkNotNull(amended) { "`amended` is required but was not set" },
+                additionalProperties.toImmutable()
+            )
     }
 
     override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumeListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumeListParams.kt
index 69ad89ee..794fce9d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumeListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumeListParams.kt
@@ -10,6 +10,19 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns the event volume for an account in a
+ * [paginated list format](../reference/pagination).
+ *
+ * The event volume is aggregated by the hour and the
+ * [timestamp](../reference/ingest#determining-event-timestamp) field is used to determine which
+ * hour an event is associated with. Note, this means that late-arriving events increment the volume
+ * count for the hour window the timestamp is in, not the latest hour window.
+ *
+ * Each item in the response contains the count of events aggregated by the hour where the start and
+ * end time are hour-aligned and in UTC. When a specific timestamp is passed in for either start or
+ * end time, the response includes the hours the timestamp falls in.
+ */
 class EventVolumeListParams
 constructor(
     private val timeframeStart: OffsetDateTime,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumes.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumes.kt
index 63840b32..e16e11bc 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumes.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/EventVolumes.kt
@@ -28,7 +28,7 @@ private constructor(
 
     fun data(): List<Data> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -52,18 +52,33 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Data>> = JsonMissing.of()
+        private var data: JsonField<MutableList<Data>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(eventVolumes: EventVolumes) = apply {
-            data = eventVolumes.data
+            data = eventVolumes.data.map { it.toMutableList() }
             additionalProperties = eventVolumes.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Data>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Data>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Data) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -85,7 +100,11 @@ private constructor(
         }
 
         fun build(): EventVolumes =
-            EventVolumes(data.map { it.toImmutable() }, additionalProperties.toImmutable())
+            EventVolumes(
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
+                additionalProperties.toImmutable()
+            )
     }
 
     /**
@@ -117,11 +136,15 @@ private constructor(
         fun timeframeStart(): OffsetDateTime = timeframeStart.getRequired("timeframe_start")
 
         /** The number of events ingested with a timestamp between the timeframe */
-        @JsonProperty("count") @ExcludeMissing fun _count() = count
+        @JsonProperty("count") @ExcludeMissing fun _count(): JsonField<Long> = count
 
-        @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-        @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -147,9 +170,9 @@ private constructor(
 
         class Builder {
 
-            private var count: JsonField<Long> = JsonMissing.of()
-            private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var count: JsonField<Long>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -201,9 +224,9 @@ private constructor(
 
             fun build(): Data =
                 Data(
-                    count,
-                    timeframeEnd,
-                    timeframeStart,
+                    checkNotNull(count) { "`count` is required but was not set" },
+                    checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                    checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Invoice.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Invoice.kt
index 08fee8df..3ed0c90d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Invoice.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Invoice.kt
@@ -296,6 +296,12 @@ private constructor(
     fun customerTaxId(): Optional<CustomerTaxId> =
         Optional.ofNullable(customerTaxId.getNullable("customer_tax_id"))
 
+    /**
+     * This field is deprecated in favor of `discounts`. If a `discounts` list is provided, the
+     * first discount in the list will be returned. If the list is empty, `None` will be returned.
+     */
+    @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonValue = discount
+
     fun discounts(): List<InvoiceLevelDiscount> = discounts.getRequired("discounts")
 
     /** When the invoice payment is due. */
@@ -427,32 +433,41 @@ private constructor(
      */
     fun willAutoIssue(): Boolean = willAutoIssue.getRequired("will_auto_issue")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * This is the final amount required to be charged to the customer and reflects the application
      * of the customer balance to the `total` of the invoice.
      */
-    @JsonProperty("amount_due") @ExcludeMissing fun _amountDue() = amountDue
+    @JsonProperty("amount_due") @ExcludeMissing fun _amountDue(): JsonField<String> = amountDue
 
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<AutoCollection> = autoCollection
 
-    @JsonProperty("billing_address") @ExcludeMissing fun _billingAddress() = billingAddress
+    @JsonProperty("billing_address")
+    @ExcludeMissing
+    fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
     /** The creation time of the resource in Orb. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /** A list of credit notes associated with the invoice */
-    @JsonProperty("credit_notes") @ExcludeMissing fun _creditNotes() = creditNotes
+    @JsonProperty("credit_notes")
+    @ExcludeMissing
+    fun _creditNotes(): JsonField<List<CreditNote>> = creditNotes
 
     /** An ISO 4217 currency string or `credits` */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     @JsonProperty("customer_balance_transactions")
     @ExcludeMissing
-    fun _customerBalanceTransactions() = customerBalanceTransactions
+    fun _customerBalanceTransactions(): JsonField<List<CustomerBalanceTransaction>> =
+        customerBalanceTransactions
 
     /**
      * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
@@ -560,18 +575,16 @@ private constructor(
      * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
      * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
      */
-    @JsonProperty("customer_tax_id") @ExcludeMissing fun _customerTaxId() = customerTaxId
-
-    /**
-     * This field is deprecated in favor of `discounts`. If a `discounts` list is provided, the
-     * first discount in the list will be returned. If the list is empty, `None` will be returned.
-     */
-    @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+    @JsonProperty("customer_tax_id")
+    @ExcludeMissing
+    fun _customerTaxId(): JsonField<CustomerTaxId> = customerTaxId
 
-    @JsonProperty("discounts") @ExcludeMissing fun _discounts() = discounts
+    @JsonProperty("discounts")
+    @ExcludeMissing
+    fun _discounts(): JsonField<List<InvoiceLevelDiscount>> = discounts
 
     /** When the invoice payment is due. */
-    @JsonProperty("due_date") @ExcludeMissing fun _dueDate() = dueDate
+    @JsonProperty("due_date") @ExcludeMissing fun _dueDate(): JsonField<OffsetDateTime> = dueDate
 
     /**
      * If the invoice has a status of `draft`, this will be the time that the invoice will be
@@ -580,113 +593,145 @@ private constructor(
      */
     @JsonProperty("eligible_to_issue_at")
     @ExcludeMissing
-    fun _eligibleToIssueAt() = eligibleToIssueAt
+    fun _eligibleToIssueAt(): JsonField<OffsetDateTime> = eligibleToIssueAt
 
     /**
      * A URL for the customer-facing invoice portal. This URL expires 30 days after the invoice's
      * due date, or 60 days after being re-generated through the UI.
      */
-    @JsonProperty("hosted_invoice_url") @ExcludeMissing fun _hostedInvoiceUrl() = hostedInvoiceUrl
+    @JsonProperty("hosted_invoice_url")
+    @ExcludeMissing
+    fun _hostedInvoiceUrl(): JsonField<String> = hostedInvoiceUrl
 
     /** The scheduled date of the invoice */
-    @JsonProperty("invoice_date") @ExcludeMissing fun _invoiceDate() = invoiceDate
+    @JsonProperty("invoice_date")
+    @ExcludeMissing
+    fun _invoiceDate(): JsonField<OffsetDateTime> = invoiceDate
 
     /**
      * Automatically generated invoice number to help track and reconcile invoices. Invoice numbers
      * have a prefix such as `RFOBWG`. These can be sequential per account or customer.
      */
-    @JsonProperty("invoice_number") @ExcludeMissing fun _invoiceNumber() = invoiceNumber
+    @JsonProperty("invoice_number")
+    @ExcludeMissing
+    fun _invoiceNumber(): JsonField<String> = invoiceNumber
 
     /** The link to download the PDF representation of the `Invoice`. */
-    @JsonProperty("invoice_pdf") @ExcludeMissing fun _invoicePdf() = invoicePdf
+    @JsonProperty("invoice_pdf") @ExcludeMissing fun _invoicePdf(): JsonField<String> = invoicePdf
 
-    @JsonProperty("invoice_source") @ExcludeMissing fun _invoiceSource() = invoiceSource
+    @JsonProperty("invoice_source")
+    @ExcludeMissing
+    fun _invoiceSource(): JsonField<InvoiceSource> = invoiceSource
 
     /**
      * If the invoice failed to issue, this will be the last time it failed to issue (even if it is
      * now in a different state.)
      */
-    @JsonProperty("issue_failed_at") @ExcludeMissing fun _issueFailedAt() = issueFailedAt
+    @JsonProperty("issue_failed_at")
+    @ExcludeMissing
+    fun _issueFailedAt(): JsonField<OffsetDateTime> = issueFailedAt
 
     /**
      * If the invoice has been issued, this will be the time it transitioned to `issued` (even if it
      * is now in a different state.)
      */
-    @JsonProperty("issued_at") @ExcludeMissing fun _issuedAt() = issuedAt
+    @JsonProperty("issued_at") @ExcludeMissing fun _issuedAt(): JsonField<OffsetDateTime> = issuedAt
 
     /** The breakdown of prices in this invoice. */
-    @JsonProperty("line_items") @ExcludeMissing fun _lineItems() = lineItems
+    @JsonProperty("line_items")
+    @ExcludeMissing
+    fun _lineItems(): JsonField<List<LineItem>> = lineItems
 
-    @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+    @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-    @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+    @JsonProperty("maximum_amount")
+    @ExcludeMissing
+    fun _maximumAmount(): JsonField<String> = maximumAmount
 
     /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
-    @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+    @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-    @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+    @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-    @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+    @JsonProperty("minimum_amount")
+    @ExcludeMissing
+    fun _minimumAmount(): JsonField<String> = minimumAmount
 
     /** If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid. */
-    @JsonProperty("paid_at") @ExcludeMissing fun _paidAt() = paidAt
+    @JsonProperty("paid_at") @ExcludeMissing fun _paidAt(): JsonField<OffsetDateTime> = paidAt
 
     /** A list of payment attempts associated with the invoice */
-    @JsonProperty("payment_attempts") @ExcludeMissing fun _paymentAttempts() = paymentAttempts
+    @JsonProperty("payment_attempts")
+    @ExcludeMissing
+    fun _paymentAttempts(): JsonField<List<PaymentAttempt>> = paymentAttempts
 
     /**
      * If payment was attempted on this invoice but failed, this will be the time of the most recent
      * attempt.
      */
-    @JsonProperty("payment_failed_at") @ExcludeMissing fun _paymentFailedAt() = paymentFailedAt
+    @JsonProperty("payment_failed_at")
+    @ExcludeMissing
+    fun _paymentFailedAt(): JsonField<OffsetDateTime> = paymentFailedAt
 
     /**
      * If payment was attempted on this invoice, this will be the start time of the most recent
      * attempt. This field is especially useful for delayed-notification payment mechanisms (like
      * bank transfers), where payment can take 3 days or more.
      */
-    @JsonProperty("payment_started_at") @ExcludeMissing fun _paymentStartedAt() = paymentStartedAt
+    @JsonProperty("payment_started_at")
+    @ExcludeMissing
+    fun _paymentStartedAt(): JsonField<OffsetDateTime> = paymentStartedAt
 
     /**
      * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to be
      * issued.
      */
-    @JsonProperty("scheduled_issue_at") @ExcludeMissing fun _scheduledIssueAt() = scheduledIssueAt
+    @JsonProperty("scheduled_issue_at")
+    @ExcludeMissing
+    fun _scheduledIssueAt(): JsonField<OffsetDateTime> = scheduledIssueAt
 
-    @JsonProperty("shipping_address") @ExcludeMissing fun _shippingAddress() = shippingAddress
+    @JsonProperty("shipping_address")
+    @ExcludeMissing
+    fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("subscription") @ExcludeMissing fun _subscription() = subscription
+    @JsonProperty("subscription")
+    @ExcludeMissing
+    fun _subscription(): JsonField<Subscription> = subscription
 
     /** The total before any discounts and minimums are applied. */
-    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
     /**
      * If the invoice failed to sync, this will be the last time an external invoicing provider sync
      * was attempted. This field will always be `null` for invoices using Orb Invoicing.
      */
-    @JsonProperty("sync_failed_at") @ExcludeMissing fun _syncFailedAt() = syncFailedAt
+    @JsonProperty("sync_failed_at")
+    @ExcludeMissing
+    fun _syncFailedAt(): JsonField<OffsetDateTime> = syncFailedAt
 
     /** The total after any minimums and discounts have been applied. */
-    @JsonProperty("total") @ExcludeMissing fun _total() = total
+    @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
     /**
      * If the invoice has a status of `void`, this gives a timestamp when the invoice was voided.
      */
-    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt() = voidedAt
+    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt(): JsonField<OffsetDateTime> = voidedAt
 
     /**
      * This is true if the invoice will be automatically issued in the future, and false otherwise.
      */
-    @JsonProperty("will_auto_issue") @ExcludeMissing fun _willAutoIssue() = willAutoIssue
+    @JsonProperty("will_auto_issue")
+    @ExcludeMissing
+    fun _willAutoIssue(): JsonField<Boolean> = willAutoIssue
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -749,48 +794,49 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amountDue: JsonField<String> = JsonMissing.of()
-        private var autoCollection: JsonField<AutoCollection> = JsonMissing.of()
-        private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var creditNotes: JsonField<List<CreditNote>> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var customerBalanceTransactions: JsonField<List<CustomerBalanceTransaction>> =
-            JsonMissing.of()
-        private var customerTaxId: JsonField<CustomerTaxId> = JsonMissing.of()
-        private var discount: JsonValue = JsonMissing.of()
-        private var discounts: JsonField<List<InvoiceLevelDiscount>> = JsonMissing.of()
-        private var dueDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var eligibleToIssueAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var hostedInvoiceUrl: JsonField<String> = JsonMissing.of()
-        private var invoiceDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var invoiceNumber: JsonField<String> = JsonMissing.of()
-        private var invoicePdf: JsonField<String> = JsonMissing.of()
-        private var invoiceSource: JsonField<InvoiceSource> = JsonMissing.of()
-        private var issueFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var issuedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var lineItems: JsonField<List<LineItem>> = JsonMissing.of()
-        private var maximum: JsonField<Maximum> = JsonMissing.of()
-        private var maximumAmount: JsonField<String> = JsonMissing.of()
-        private var memo: JsonField<String> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimum: JsonField<Minimum> = JsonMissing.of()
-        private var minimumAmount: JsonField<String> = JsonMissing.of()
-        private var paidAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var paymentAttempts: JsonField<List<PaymentAttempt>> = JsonMissing.of()
-        private var paymentFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var paymentStartedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var scheduledIssueAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var subscription: JsonField<Subscription> = JsonMissing.of()
-        private var subtotal: JsonField<String> = JsonMissing.of()
-        private var syncFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var total: JsonField<String> = JsonMissing.of()
-        private var voidedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var willAutoIssue: JsonField<Boolean> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amountDue: JsonField<String>? = null
+        private var autoCollection: JsonField<AutoCollection>? = null
+        private var billingAddress: JsonField<BillingAddress>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var creditNotes: JsonField<MutableList<CreditNote>>? = null
+        private var currency: JsonField<String>? = null
+        private var customer: JsonField<Customer>? = null
+        private var customerBalanceTransactions:
+            JsonField<MutableList<CustomerBalanceTransaction>>? =
+            null
+        private var customerTaxId: JsonField<CustomerTaxId>? = null
+        private var discount: JsonValue? = null
+        private var discounts: JsonField<MutableList<InvoiceLevelDiscount>>? = null
+        private var dueDate: JsonField<OffsetDateTime>? = null
+        private var eligibleToIssueAt: JsonField<OffsetDateTime>? = null
+        private var hostedInvoiceUrl: JsonField<String>? = null
+        private var invoiceDate: JsonField<OffsetDateTime>? = null
+        private var invoiceNumber: JsonField<String>? = null
+        private var invoicePdf: JsonField<String>? = null
+        private var invoiceSource: JsonField<InvoiceSource>? = null
+        private var issueFailedAt: JsonField<OffsetDateTime>? = null
+        private var issuedAt: JsonField<OffsetDateTime>? = null
+        private var lineItems: JsonField<MutableList<LineItem>>? = null
+        private var maximum: JsonField<Maximum>? = null
+        private var maximumAmount: JsonField<String>? = null
+        private var memo: JsonField<String>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimum: JsonField<Minimum>? = null
+        private var minimumAmount: JsonField<String>? = null
+        private var paidAt: JsonField<OffsetDateTime>? = null
+        private var paymentAttempts: JsonField<MutableList<PaymentAttempt>>? = null
+        private var paymentFailedAt: JsonField<OffsetDateTime>? = null
+        private var paymentStartedAt: JsonField<OffsetDateTime>? = null
+        private var scheduledIssueAt: JsonField<OffsetDateTime>? = null
+        private var shippingAddress: JsonField<ShippingAddress>? = null
+        private var status: JsonField<Status>? = null
+        private var subscription: JsonField<Subscription>? = null
+        private var subtotal: JsonField<String>? = null
+        private var syncFailedAt: JsonField<OffsetDateTime>? = null
+        private var total: JsonField<String>? = null
+        private var voidedAt: JsonField<OffsetDateTime>? = null
+        private var willAutoIssue: JsonField<Boolean>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -800,13 +846,14 @@ private constructor(
             autoCollection = invoice.autoCollection
             billingAddress = invoice.billingAddress
             createdAt = invoice.createdAt
-            creditNotes = invoice.creditNotes
+            creditNotes = invoice.creditNotes.map { it.toMutableList() }
             currency = invoice.currency
             customer = invoice.customer
-            customerBalanceTransactions = invoice.customerBalanceTransactions
+            customerBalanceTransactions =
+                invoice.customerBalanceTransactions.map { it.toMutableList() }
             customerTaxId = invoice.customerTaxId
             discount = invoice.discount
-            discounts = invoice.discounts
+            discounts = invoice.discounts.map { it.toMutableList() }
             dueDate = invoice.dueDate
             eligibleToIssueAt = invoice.eligibleToIssueAt
             hostedInvoiceUrl = invoice.hostedInvoiceUrl
@@ -816,7 +863,7 @@ private constructor(
             invoiceSource = invoice.invoiceSource
             issueFailedAt = invoice.issueFailedAt
             issuedAt = invoice.issuedAt
-            lineItems = invoice.lineItems
+            lineItems = invoice.lineItems.map { it.toMutableList() }
             maximum = invoice.maximum
             maximumAmount = invoice.maximumAmount
             memo = invoice.memo
@@ -824,7 +871,7 @@ private constructor(
             minimum = invoice.minimum
             minimumAmount = invoice.minimumAmount
             paidAt = invoice.paidAt
-            paymentAttempts = invoice.paymentAttempts
+            paymentAttempts = invoice.paymentAttempts.map { it.toMutableList() }
             paymentFailedAt = invoice.paymentFailedAt
             paymentStartedAt = invoice.paymentStartedAt
             scheduledIssueAt = invoice.scheduledIssueAt
@@ -862,8 +909,11 @@ private constructor(
             this.autoCollection = autoCollection
         }
 
-        fun billingAddress(billingAddress: BillingAddress) =
-            billingAddress(JsonField.of(billingAddress))
+        fun billingAddress(billingAddress: BillingAddress?) =
+            billingAddress(JsonField.ofNullable(billingAddress))
+
+        fun billingAddress(billingAddress: Optional<BillingAddress>) =
+            billingAddress(billingAddress.orElse(null))
 
         fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
             this.billingAddress = billingAddress
@@ -880,7 +930,21 @@ private constructor(
 
         /** A list of credit notes associated with the invoice */
         fun creditNotes(creditNotes: JsonField<List<CreditNote>>) = apply {
-            this.creditNotes = creditNotes
+            this.creditNotes = creditNotes.map { it.toMutableList() }
+        }
+
+        /** A list of credit notes associated with the invoice */
+        fun addCreditNote(creditNote: CreditNote) = apply {
+            creditNotes =
+                (creditNotes ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(creditNote)
+                }
         }
 
         /** An ISO 4217 currency string or `credits` */
@@ -899,7 +963,24 @@ private constructor(
 
         fun customerBalanceTransactions(
             customerBalanceTransactions: JsonField<List<CustomerBalanceTransaction>>
-        ) = apply { this.customerBalanceTransactions = customerBalanceTransactions }
+        ) = apply {
+            this.customerBalanceTransactions =
+                customerBalanceTransactions.map { it.toMutableList() }
+        }
+
+        fun addCustomerBalanceTransaction(customerBalanceTransaction: CustomerBalanceTransaction) =
+            apply {
+                customerBalanceTransactions =
+                    (customerBalanceTransactions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(customerBalanceTransaction)
+                    }
+            }
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1007,7 +1088,117 @@ private constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun customerTaxId(customerTaxId: CustomerTaxId) = customerTaxId(JsonField.of(customerTaxId))
+        fun customerTaxId(customerTaxId: CustomerTaxId?) =
+            customerTaxId(JsonField.ofNullable(customerTaxId))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun customerTaxId(customerTaxId: Optional<CustomerTaxId>) =
+            customerTaxId(customerTaxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1129,7 +1320,20 @@ private constructor(
         fun discounts(discounts: List<InvoiceLevelDiscount>) = discounts(JsonField.of(discounts))
 
         fun discounts(discounts: JsonField<List<InvoiceLevelDiscount>>) = apply {
-            this.discounts = discounts
+            this.discounts = discounts.map { it.toMutableList() }
+        }
+
+        fun addDiscount(discount: InvoiceLevelDiscount) = apply {
+            discounts =
+                (discounts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discount)
+                }
         }
 
         /** When the invoice payment is due. */
@@ -1143,8 +1347,16 @@ private constructor(
          * eligible to be issued, otherwise it will be `null`. If `auto-issue` is true, the invoice
          * will automatically begin issuing at this time.
          */
-        fun eligibleToIssueAt(eligibleToIssueAt: OffsetDateTime) =
-            eligibleToIssueAt(JsonField.of(eligibleToIssueAt))
+        fun eligibleToIssueAt(eligibleToIssueAt: OffsetDateTime?) =
+            eligibleToIssueAt(JsonField.ofNullable(eligibleToIssueAt))
+
+        /**
+         * If the invoice has a status of `draft`, this will be the time that the invoice will be
+         * eligible to be issued, otherwise it will be `null`. If `auto-issue` is true, the invoice
+         * will automatically begin issuing at this time.
+         */
+        fun eligibleToIssueAt(eligibleToIssueAt: Optional<OffsetDateTime>) =
+            eligibleToIssueAt(eligibleToIssueAt.orElse(null))
 
         /**
          * If the invoice has a status of `draft`, this will be the time that the invoice will be
@@ -1159,8 +1371,15 @@ private constructor(
          * A URL for the customer-facing invoice portal. This URL expires 30 days after the
          * invoice's due date, or 60 days after being re-generated through the UI.
          */
-        fun hostedInvoiceUrl(hostedInvoiceUrl: String) =
-            hostedInvoiceUrl(JsonField.of(hostedInvoiceUrl))
+        fun hostedInvoiceUrl(hostedInvoiceUrl: String?) =
+            hostedInvoiceUrl(JsonField.ofNullable(hostedInvoiceUrl))
+
+        /**
+         * A URL for the customer-facing invoice portal. This URL expires 30 days after the
+         * invoice's due date, or 60 days after being re-generated through the UI.
+         */
+        fun hostedInvoiceUrl(hostedInvoiceUrl: Optional<String>) =
+            hostedInvoiceUrl(hostedInvoiceUrl.orElse(null))
 
         /**
          * A URL for the customer-facing invoice portal. This URL expires 30 days after the
@@ -1193,7 +1412,10 @@ private constructor(
         }
 
         /** The link to download the PDF representation of the `Invoice`. */
-        fun invoicePdf(invoicePdf: String) = invoicePdf(JsonField.of(invoicePdf))
+        fun invoicePdf(invoicePdf: String?) = invoicePdf(JsonField.ofNullable(invoicePdf))
+
+        /** The link to download the PDF representation of the `Invoice`. */
+        fun invoicePdf(invoicePdf: Optional<String>) = invoicePdf(invoicePdf.orElse(null))
 
         /** The link to download the PDF representation of the `Invoice`. */
         fun invoicePdf(invoicePdf: JsonField<String>) = apply { this.invoicePdf = invoicePdf }
@@ -1208,8 +1430,15 @@ private constructor(
          * If the invoice failed to issue, this will be the last time it failed to issue (even if it
          * is now in a different state.)
          */
-        fun issueFailedAt(issueFailedAt: OffsetDateTime) =
-            issueFailedAt(JsonField.of(issueFailedAt))
+        fun issueFailedAt(issueFailedAt: OffsetDateTime?) =
+            issueFailedAt(JsonField.ofNullable(issueFailedAt))
+
+        /**
+         * If the invoice failed to issue, this will be the last time it failed to issue (even if it
+         * is now in a different state.)
+         */
+        fun issueFailedAt(issueFailedAt: Optional<OffsetDateTime>) =
+            issueFailedAt(issueFailedAt.orElse(null))
 
         /**
          * If the invoice failed to issue, this will be the last time it failed to issue (even if it
@@ -1223,7 +1452,13 @@ private constructor(
          * If the invoice has been issued, this will be the time it transitioned to `issued` (even
          * if it is now in a different state.)
          */
-        fun issuedAt(issuedAt: OffsetDateTime) = issuedAt(JsonField.of(issuedAt))
+        fun issuedAt(issuedAt: OffsetDateTime?) = issuedAt(JsonField.ofNullable(issuedAt))
+
+        /**
+         * If the invoice has been issued, this will be the time it transitioned to `issued` (even
+         * if it is now in a different state.)
+         */
+        fun issuedAt(issuedAt: Optional<OffsetDateTime>) = issuedAt(issuedAt.orElse(null))
 
         /**
          * If the invoice has been issued, this will be the time it transitioned to `issued` (even
@@ -1235,20 +1470,45 @@ private constructor(
         fun lineItems(lineItems: List<LineItem>) = lineItems(JsonField.of(lineItems))
 
         /** The breakdown of prices in this invoice. */
-        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply { this.lineItems = lineItems }
+        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply {
+            this.lineItems = lineItems.map { it.toMutableList() }
+        }
 
-        fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+        /** The breakdown of prices in this invoice. */
+        fun addLineItem(lineItem: LineItem) = apply {
+            lineItems =
+                (lineItems ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(lineItem)
+                }
+        }
+
+        fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+        fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
         fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-        fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+        fun maximumAmount(maximumAmount: String?) =
+            maximumAmount(JsonField.ofNullable(maximumAmount))
+
+        fun maximumAmount(maximumAmount: Optional<String>) =
+            maximumAmount(maximumAmount.orElse(null))
 
         fun maximumAmount(maximumAmount: JsonField<String>) = apply {
             this.maximumAmount = maximumAmount
         }
 
         /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
-        fun memo(memo: String) = memo(JsonField.of(memo))
+        fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+        /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+        fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
         /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
         fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -1267,11 +1527,17 @@ private constructor(
          */
         fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-        fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+        fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+        fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
         fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-        fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+        fun minimumAmount(minimumAmount: String?) =
+            minimumAmount(JsonField.ofNullable(minimumAmount))
+
+        fun minimumAmount(minimumAmount: Optional<String>) =
+            minimumAmount(minimumAmount.orElse(null))
 
         fun minimumAmount(minimumAmount: JsonField<String>) = apply {
             this.minimumAmount = minimumAmount
@@ -1280,7 +1546,12 @@ private constructor(
         /**
          * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
          */
-        fun paidAt(paidAt: OffsetDateTime) = paidAt(JsonField.of(paidAt))
+        fun paidAt(paidAt: OffsetDateTime?) = paidAt(JsonField.ofNullable(paidAt))
+
+        /**
+         * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
+         */
+        fun paidAt(paidAt: Optional<OffsetDateTime>) = paidAt(paidAt.orElse(null))
 
         /**
          * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
@@ -1293,15 +1564,36 @@ private constructor(
 
         /** A list of payment attempts associated with the invoice */
         fun paymentAttempts(paymentAttempts: JsonField<List<PaymentAttempt>>) = apply {
-            this.paymentAttempts = paymentAttempts
+            this.paymentAttempts = paymentAttempts.map { it.toMutableList() }
+        }
+
+        /** A list of payment attempts associated with the invoice */
+        fun addPaymentAttempt(paymentAttempt: PaymentAttempt) = apply {
+            paymentAttempts =
+                (paymentAttempts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(paymentAttempt)
+                }
         }
 
         /**
          * If payment was attempted on this invoice but failed, this will be the time of the most
          * recent attempt.
          */
-        fun paymentFailedAt(paymentFailedAt: OffsetDateTime) =
-            paymentFailedAt(JsonField.of(paymentFailedAt))
+        fun paymentFailedAt(paymentFailedAt: OffsetDateTime?) =
+            paymentFailedAt(JsonField.ofNullable(paymentFailedAt))
+
+        /**
+         * If payment was attempted on this invoice but failed, this will be the time of the most
+         * recent attempt.
+         */
+        fun paymentFailedAt(paymentFailedAt: Optional<OffsetDateTime>) =
+            paymentFailedAt(paymentFailedAt.orElse(null))
 
         /**
          * If payment was attempted on this invoice but failed, this will be the time of the most
@@ -1316,8 +1608,16 @@ private constructor(
          * attempt. This field is especially useful for delayed-notification payment mechanisms
          * (like bank transfers), where payment can take 3 days or more.
          */
-        fun paymentStartedAt(paymentStartedAt: OffsetDateTime) =
-            paymentStartedAt(JsonField.of(paymentStartedAt))
+        fun paymentStartedAt(paymentStartedAt: OffsetDateTime?) =
+            paymentStartedAt(JsonField.ofNullable(paymentStartedAt))
+
+        /**
+         * If payment was attempted on this invoice, this will be the start time of the most recent
+         * attempt. This field is especially useful for delayed-notification payment mechanisms
+         * (like bank transfers), where payment can take 3 days or more.
+         */
+        fun paymentStartedAt(paymentStartedAt: Optional<OffsetDateTime>) =
+            paymentStartedAt(paymentStartedAt.orElse(null))
 
         /**
          * If payment was attempted on this invoice, this will be the start time of the most recent
@@ -1332,8 +1632,15 @@ private constructor(
          * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
          * be issued.
          */
-        fun scheduledIssueAt(scheduledIssueAt: OffsetDateTime) =
-            scheduledIssueAt(JsonField.of(scheduledIssueAt))
+        fun scheduledIssueAt(scheduledIssueAt: OffsetDateTime?) =
+            scheduledIssueAt(JsonField.ofNullable(scheduledIssueAt))
+
+        /**
+         * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
+         * be issued.
+         */
+        fun scheduledIssueAt(scheduledIssueAt: Optional<OffsetDateTime>) =
+            scheduledIssueAt(scheduledIssueAt.orElse(null))
 
         /**
          * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
@@ -1343,8 +1650,11 @@ private constructor(
             this.scheduledIssueAt = scheduledIssueAt
         }
 
-        fun shippingAddress(shippingAddress: ShippingAddress) =
-            shippingAddress(JsonField.of(shippingAddress))
+        fun shippingAddress(shippingAddress: ShippingAddress?) =
+            shippingAddress(JsonField.ofNullable(shippingAddress))
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
 
         fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
             this.shippingAddress = shippingAddress
@@ -1354,7 +1664,11 @@ private constructor(
 
         fun status(status: JsonField<Status>) = apply { this.status = status }
 
-        fun subscription(subscription: Subscription) = subscription(JsonField.of(subscription))
+        fun subscription(subscription: Subscription?) =
+            subscription(JsonField.ofNullable(subscription))
+
+        fun subscription(subscription: Optional<Subscription>) =
+            subscription(subscription.orElse(null))
 
         fun subscription(subscription: JsonField<Subscription>) = apply {
             this.subscription = subscription
@@ -1370,7 +1684,15 @@ private constructor(
          * If the invoice failed to sync, this will be the last time an external invoicing provider
          * sync was attempted. This field will always be `null` for invoices using Orb Invoicing.
          */
-        fun syncFailedAt(syncFailedAt: OffsetDateTime) = syncFailedAt(JsonField.of(syncFailedAt))
+        fun syncFailedAt(syncFailedAt: OffsetDateTime?) =
+            syncFailedAt(JsonField.ofNullable(syncFailedAt))
+
+        /**
+         * If the invoice failed to sync, this will be the last time an external invoicing provider
+         * sync was attempted. This field will always be `null` for invoices using Orb Invoicing.
+         */
+        fun syncFailedAt(syncFailedAt: Optional<OffsetDateTime>) =
+            syncFailedAt(syncFailedAt.orElse(null))
 
         /**
          * If the invoice failed to sync, this will be the last time an external invoicing provider
@@ -1390,7 +1712,13 @@ private constructor(
          * If the invoice has a status of `void`, this gives a timestamp when the invoice was
          * voided.
          */
-        fun voidedAt(voidedAt: OffsetDateTime) = voidedAt(JsonField.of(voidedAt))
+        fun voidedAt(voidedAt: OffsetDateTime?) = voidedAt(JsonField.ofNullable(voidedAt))
+
+        /**
+         * If the invoice has a status of `void`, this gives a timestamp when the invoice was
+         * voided.
+         */
+        fun voidedAt(voidedAt: Optional<OffsetDateTime>) = voidedAt(voidedAt.orElse(null))
 
         /**
          * If the invoice has a status of `void`, this gives a timestamp when the invoice was
@@ -1433,47 +1761,56 @@ private constructor(
 
         fun build(): Invoice =
             Invoice(
-                id,
-                amountDue,
-                autoCollection,
-                billingAddress,
-                createdAt,
-                creditNotes.map { it.toImmutable() },
-                currency,
-                customer,
-                customerBalanceTransactions.map { it.toImmutable() },
-                customerTaxId,
-                discount,
-                discounts.map { it.toImmutable() },
-                dueDate,
-                eligibleToIssueAt,
-                hostedInvoiceUrl,
-                invoiceDate,
-                invoiceNumber,
-                invoicePdf,
-                invoiceSource,
-                issueFailedAt,
-                issuedAt,
-                lineItems.map { it.toImmutable() },
-                maximum,
-                maximumAmount,
-                memo,
-                metadata,
-                minimum,
-                minimumAmount,
-                paidAt,
-                paymentAttempts.map { it.toImmutable() },
-                paymentFailedAt,
-                paymentStartedAt,
-                scheduledIssueAt,
-                shippingAddress,
-                status,
-                subscription,
-                subtotal,
-                syncFailedAt,
-                total,
-                voidedAt,
-                willAutoIssue,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amountDue) { "`amountDue` is required but was not set" },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingAddress) { "`billingAddress` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(creditNotes) { "`creditNotes` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(customerBalanceTransactions) {
+                        "`customerBalanceTransactions` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(customerTaxId) { "`customerTaxId` is required but was not set" },
+                checkNotNull(discount) { "`discount` is required but was not set" },
+                checkNotNull(discounts) { "`discounts` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(dueDate) { "`dueDate` is required but was not set" },
+                checkNotNull(eligibleToIssueAt) {
+                    "`eligibleToIssueAt` is required but was not set"
+                },
+                checkNotNull(hostedInvoiceUrl) { "`hostedInvoiceUrl` is required but was not set" },
+                checkNotNull(invoiceDate) { "`invoiceDate` is required but was not set" },
+                checkNotNull(invoiceNumber) { "`invoiceNumber` is required but was not set" },
+                checkNotNull(invoicePdf) { "`invoicePdf` is required but was not set" },
+                checkNotNull(invoiceSource) { "`invoiceSource` is required but was not set" },
+                checkNotNull(issueFailedAt) { "`issueFailedAt` is required but was not set" },
+                checkNotNull(issuedAt) { "`issuedAt` is required but was not set" },
+                checkNotNull(lineItems) { "`lineItems` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(maximum) { "`maximum` is required but was not set" },
+                checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                checkNotNull(memo) { "`memo` is required but was not set" },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimum) { "`minimum` is required but was not set" },
+                checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                checkNotNull(paidAt) { "`paidAt` is required but was not set" },
+                checkNotNull(paymentAttempts) { "`paymentAttempts` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(paymentFailedAt) { "`paymentFailedAt` is required but was not set" },
+                checkNotNull(paymentStartedAt) { "`paymentStartedAt` is required but was not set" },
+                checkNotNull(scheduledIssueAt) { "`scheduledIssueAt` is required but was not set" },
+                checkNotNull(shippingAddress) { "`shippingAddress` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(subscription) { "`subscription` is required but was not set" },
+                checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                checkNotNull(syncFailedAt) { "`syncFailedAt` is required but was not set" },
+                checkNotNull(total) { "`total` is required but was not set" },
+                checkNotNull(voidedAt) { "`voidedAt` is required but was not set" },
+                checkNotNull(willAutoIssue) { "`willAutoIssue` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -1525,17 +1862,21 @@ private constructor(
             Optional.ofNullable(previouslyAttemptedAt.getNullable("previously_attempted_at"))
 
         /** True only if auto-collection is enabled for this invoice. */
-        @JsonProperty("enabled") @ExcludeMissing fun _enabled() = enabled
+        @JsonProperty("enabled") @ExcludeMissing fun _enabled(): JsonField<Boolean> = enabled
 
         /**
          * If the invoice is scheduled for auto-collection, this field will reflect when the next
          * attempt will occur. If dunning has been exhausted, or auto-collection is not enabled for
          * this invoice, this field will be `null`.
          */
-        @JsonProperty("next_attempt_at") @ExcludeMissing fun _nextAttemptAt() = nextAttemptAt
+        @JsonProperty("next_attempt_at")
+        @ExcludeMissing
+        fun _nextAttemptAt(): JsonField<OffsetDateTime> = nextAttemptAt
 
         /** Number of auto-collection payment attempts. */
-        @JsonProperty("num_attempts") @ExcludeMissing fun _numAttempts() = numAttempts
+        @JsonProperty("num_attempts")
+        @ExcludeMissing
+        fun _numAttempts(): JsonField<Long> = numAttempts
 
         /**
          * If Orb has ever attempted payment auto-collection for this invoice, this field will
@@ -1547,7 +1888,7 @@ private constructor(
          */
         @JsonProperty("previously_attempted_at")
         @ExcludeMissing
-        fun _previouslyAttemptedAt() = previouslyAttemptedAt
+        fun _previouslyAttemptedAt(): JsonField<OffsetDateTime> = previouslyAttemptedAt
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1574,10 +1915,10 @@ private constructor(
 
         class Builder {
 
-            private var enabled: JsonField<Boolean> = JsonMissing.of()
-            private var nextAttemptAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var numAttempts: JsonField<Long> = JsonMissing.of()
-            private var previouslyAttemptedAt: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var enabled: JsonField<Boolean>? = null
+            private var nextAttemptAt: JsonField<OffsetDateTime>? = null
+            private var numAttempts: JsonField<Long>? = null
+            private var previouslyAttemptedAt: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1590,7 +1931,14 @@ private constructor(
             }
 
             /** True only if auto-collection is enabled for this invoice. */
-            fun enabled(enabled: Boolean) = enabled(JsonField.of(enabled))
+            fun enabled(enabled: Boolean?) = enabled(JsonField.ofNullable(enabled))
+
+            /** True only if auto-collection is enabled for this invoice. */
+            fun enabled(enabled: Boolean) = enabled(enabled as Boolean?)
+
+            /** True only if auto-collection is enabled for this invoice. */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun enabled(enabled: Optional<Boolean>) = enabled(enabled.orElse(null) as Boolean?)
 
             /** True only if auto-collection is enabled for this invoice. */
             fun enabled(enabled: JsonField<Boolean>) = apply { this.enabled = enabled }
@@ -1600,8 +1948,16 @@ private constructor(
              * next attempt will occur. If dunning has been exhausted, or auto-collection is not
              * enabled for this invoice, this field will be `null`.
              */
-            fun nextAttemptAt(nextAttemptAt: OffsetDateTime) =
-                nextAttemptAt(JsonField.of(nextAttemptAt))
+            fun nextAttemptAt(nextAttemptAt: OffsetDateTime?) =
+                nextAttemptAt(JsonField.ofNullable(nextAttemptAt))
+
+            /**
+             * If the invoice is scheduled for auto-collection, this field will reflect when the
+             * next attempt will occur. If dunning has been exhausted, or auto-collection is not
+             * enabled for this invoice, this field will be `null`.
+             */
+            fun nextAttemptAt(nextAttemptAt: Optional<OffsetDateTime>) =
+                nextAttemptAt(nextAttemptAt.orElse(null))
 
             /**
              * If the invoice is scheduled for auto-collection, this field will reflect when the
@@ -1613,7 +1969,15 @@ private constructor(
             }
 
             /** Number of auto-collection payment attempts. */
-            fun numAttempts(numAttempts: Long) = numAttempts(JsonField.of(numAttempts))
+            fun numAttempts(numAttempts: Long?) = numAttempts(JsonField.ofNullable(numAttempts))
+
+            /** Number of auto-collection payment attempts. */
+            fun numAttempts(numAttempts: Long) = numAttempts(numAttempts as Long?)
+
+            /** Number of auto-collection payment attempts. */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun numAttempts(numAttempts: Optional<Long>) =
+                numAttempts(numAttempts.orElse(null) as Long?)
 
             /** Number of auto-collection payment attempts. */
             fun numAttempts(numAttempts: JsonField<Long>) = apply { this.numAttempts = numAttempts }
@@ -1626,8 +1990,19 @@ private constructor(
              * dunning has been exhausted (`previously_attempted_at` is non-null, but
              * `next_attempt_time` is null).
              */
-            fun previouslyAttemptedAt(previouslyAttemptedAt: OffsetDateTime) =
-                previouslyAttemptedAt(JsonField.of(previouslyAttemptedAt))
+            fun previouslyAttemptedAt(previouslyAttemptedAt: OffsetDateTime?) =
+                previouslyAttemptedAt(JsonField.ofNullable(previouslyAttemptedAt))
+
+            /**
+             * If Orb has ever attempted payment auto-collection for this invoice, this field will
+             * reflect when that attempt occurred. In conjunction with `next_attempt_at`, this can
+             * be used to tell whether the invoice is currently in dunning (that is,
+             * `previously_attempted_at` is non-null, and `next_attempt_time` is non-null), or if
+             * dunning has been exhausted (`previously_attempted_at` is non-null, but
+             * `next_attempt_time` is null).
+             */
+            fun previouslyAttemptedAt(previouslyAttemptedAt: Optional<OffsetDateTime>) =
+                previouslyAttemptedAt(previouslyAttemptedAt.orElse(null))
 
             /**
              * If Orb has ever attempted payment auto-collection for this invoice, this field will
@@ -1662,10 +2037,12 @@ private constructor(
 
             fun build(): AutoCollection =
                 AutoCollection(
-                    enabled,
-                    nextAttemptAt,
-                    numAttempts,
-                    previouslyAttemptedAt,
+                    checkNotNull(enabled) { "`enabled` is required but was not set" },
+                    checkNotNull(nextAttemptAt) { "`nextAttemptAt` is required but was not set" },
+                    checkNotNull(numAttempts) { "`numAttempts` is required but was not set" },
+                    checkNotNull(previouslyAttemptedAt) {
+                        "`previouslyAttemptedAt` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1727,17 +2104,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1766,12 +2145,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1785,27 +2164,39 @@ private constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -1830,12 +2221,12 @@ private constructor(
 
             fun build(): BillingAddress =
                 BillingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1905,26 +2296,28 @@ private constructor(
         fun voidedAt(): Optional<OffsetDateTime> =
             Optional.ofNullable(voidedAt.getNullable("voided_at"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("credit_note_number")
         @ExcludeMissing
-        fun _creditNoteNumber() = creditNoteNumber
+        fun _creditNoteNumber(): JsonField<String> = creditNoteNumber
 
         /** An optional memo supplied on the credit note. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
-        @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
-        @JsonProperty("total") @ExcludeMissing fun _total() = total
+        @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<String> = type
 
         /**
          * If the credit note has a status of `void`, this gives a timestamp when the credit note
          * was voided.
          */
-        @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt() = voidedAt
+        @JsonProperty("voided_at")
+        @ExcludeMissing
+        fun _voidedAt(): JsonField<OffsetDateTime> = voidedAt
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1954,13 +2347,13 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var creditNoteNumber: JsonField<String> = JsonMissing.of()
-            private var memo: JsonField<String> = JsonMissing.of()
-            private var reason: JsonField<String> = JsonMissing.of()
-            private var total: JsonField<String> = JsonMissing.of()
-            private var type: JsonField<String> = JsonMissing.of()
-            private var voidedAt: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var creditNoteNumber: JsonField<String>? = null
+            private var memo: JsonField<String>? = null
+            private var reason: JsonField<String>? = null
+            private var total: JsonField<String>? = null
+            private var type: JsonField<String>? = null
+            private var voidedAt: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1987,7 +2380,10 @@ private constructor(
             }
 
             /** An optional memo supplied on the credit note. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo supplied on the credit note. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo supplied on the credit note. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -2008,7 +2404,13 @@ private constructor(
              * If the credit note has a status of `void`, this gives a timestamp when the credit
              * note was voided.
              */
-            fun voidedAt(voidedAt: OffsetDateTime) = voidedAt(JsonField.of(voidedAt))
+            fun voidedAt(voidedAt: OffsetDateTime?) = voidedAt(JsonField.ofNullable(voidedAt))
+
+            /**
+             * If the credit note has a status of `void`, this gives a timestamp when the credit
+             * note was voided.
+             */
+            fun voidedAt(voidedAt: Optional<OffsetDateTime>) = voidedAt(voidedAt.orElse(null))
 
             /**
              * If the credit note has a status of `void`, this gives a timestamp when the credit
@@ -2037,13 +2439,15 @@ private constructor(
 
             fun build(): CreditNote =
                 CreditNote(
-                    id,
-                    creditNoteNumber,
-                    memo,
-                    reason,
-                    total,
-                    type,
-                    voidedAt,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(creditNoteNumber) {
+                        "`creditNoteNumber` is required but was not set"
+                    },
+                    checkNotNull(memo) { "`memo` is required but was not set" },
+                    checkNotNull(reason) { "`reason` is required but was not set" },
+                    checkNotNull(total) { "`total` is required but was not set" },
+                    checkNotNull(type) { "`type` is required but was not set" },
+                    checkNotNull(voidedAt) { "`voidedAt` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2083,11 +2487,11 @@ private constructor(
         fun externalCustomerId(): Optional<String> =
             Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("external_customer_id")
         @ExcludeMissing
-        fun _externalCustomerId() = externalCustomerId
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2112,8 +2516,8 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalCustomerId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2127,8 +2531,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun externalCustomerId(externalCustomerId: String) =
-                externalCustomerId(JsonField.of(externalCustomerId))
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+            fun externalCustomerId(externalCustomerId: Optional<String>) =
+                externalCustomerId(externalCustomerId.orElse(null))
 
             fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                 this.externalCustomerId = externalCustomerId
@@ -2155,8 +2562,10 @@ private constructor(
 
             fun build(): Customer =
                 Customer(
-                    id,
-                    externalCustomerId,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalCustomerId) {
+                        "`externalCustomerId` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2248,36 +2657,46 @@ private constructor(
         fun type(): Type = type.getRequired("type")
 
         /** A unique id for this transaction. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("action") @ExcludeMissing fun _action() = action
+        @JsonProperty("action") @ExcludeMissing fun _action(): JsonField<Action> = action
 
         /** The value of the amount changed in the transaction. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The creation time of this transaction. */
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_note") @ExcludeMissing fun _creditNote() = creditNote
+        @JsonProperty("credit_note")
+        @ExcludeMissing
+        fun _creditNote(): JsonField<CreditNote> = creditNote
 
         /** An optional description provided for manual customer balance adjustments. */
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * The new value of the customer's balance prior to the transaction, in the customer's
          * currency.
          */
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<String> = endingBalance
 
-        @JsonProperty("invoice") @ExcludeMissing fun _invoice() = invoice
+        @JsonProperty("invoice") @ExcludeMissing fun _invoice(): JsonField<Invoice> = invoice
 
         /**
          * The original value of the customer's balance prior to the transaction, in the customer's
          * currency.
          */
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<String> = startingBalance
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2310,16 +2729,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var action: JsonField<Action> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditNote: JsonField<CreditNote> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<String> = JsonMissing.of()
-            private var invoice: JsonField<Invoice> = JsonMissing.of()
-            private var startingBalance: JsonField<String> = JsonMissing.of()
-            private var type: JsonField<Type> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var action: JsonField<Action>? = null
+            private var amount: JsonField<String>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditNote: JsonField<CreditNote>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<String>? = null
+            private var invoice: JsonField<Invoice>? = null
+            private var startingBalance: JsonField<String>? = null
+            private var type: JsonField<Type>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2362,14 +2781,19 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditNote(creditNote: CreditNote) = creditNote(JsonField.of(creditNote))
+            fun creditNote(creditNote: CreditNote?) = creditNote(JsonField.ofNullable(creditNote))
+
+            fun creditNote(creditNote: Optional<CreditNote>) = creditNote(creditNote.orElse(null))
 
             fun creditNote(creditNote: JsonField<CreditNote>) = apply {
                 this.creditNote = creditNote
             }
 
             /** An optional description provided for manual customer balance adjustments. */
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            /** An optional description provided for manual customer balance adjustments. */
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             /** An optional description provided for manual customer balance adjustments. */
             fun description(description: JsonField<String>) = apply {
@@ -2390,7 +2814,9 @@ private constructor(
                 this.endingBalance = endingBalance
             }
 
-            fun invoice(invoice: Invoice) = invoice(JsonField.of(invoice))
+            fun invoice(invoice: Invoice?) = invoice(JsonField.ofNullable(invoice))
+
+            fun invoice(invoice: Optional<Invoice>) = invoice(invoice.orElse(null))
 
             fun invoice(invoice: JsonField<Invoice>) = apply { this.invoice = invoice }
 
@@ -2434,16 +2860,18 @@ private constructor(
 
             fun build(): CustomerBalanceTransaction =
                 CustomerBalanceTransaction(
-                    id,
-                    action,
-                    amount,
-                    createdAt,
-                    creditNote,
-                    description,
-                    endingBalance,
-                    invoice,
-                    startingBalance,
-                    type,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(action) { "`action` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditNote) { "`creditNote` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(invoice) { "`invoice` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(type) { "`type` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2556,7 +2984,7 @@ private constructor(
             fun id(): String = id.getRequired("id")
 
             /** The id of the Credit note */
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2580,7 +3008,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2617,7 +3045,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): CreditNote = CreditNote(id, additionalProperties.toImmutable())
+                fun build(): CreditNote =
+                    CreditNote(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -2653,7 +3085,7 @@ private constructor(
             fun id(): String = id.getRequired("id")
 
             /** The Invoice id */
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2677,7 +3109,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2714,7 +3146,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): Invoice = Invoice(id, additionalProperties.toImmutable())
+                fun build(): Invoice =
+                    Invoice(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -2936,11 +3372,11 @@ private constructor(
 
         fun value(): String = value.getRequired("value")
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
-        @JsonProperty("value") @ExcludeMissing fun _value() = value
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2966,9 +3402,9 @@ private constructor(
 
         class Builder {
 
-            private var country: JsonField<Country> = JsonMissing.of()
-            private var type: JsonField<Type> = JsonMissing.of()
-            private var value: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3012,9 +3448,9 @@ private constructor(
 
             fun build(): CustomerTaxId =
                 CustomerTaxId(
-                    country,
-                    type,
-                    value,
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(type) { "`type` is required but was not set" },
+                    checkNotNull(value) { "`value` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4420,33 +4856,39 @@ private constructor(
         fun taxAmounts(): List<TaxAmount> = taxAmounts.getRequired("tax_amounts")
 
         /** A unique ID for this line item. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The final amount after any discounts or minimums. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
         /** The end date of the range of time applied for this line item's price. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * [DEPRECATED] For configured prices that are split by a grouping key, this will be
          * populated with the key and a value. The `amount` and `subtotal` will be the values for
          * this particular grouping.
          */
-        @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+        @JsonProperty("grouping") @ExcludeMissing fun _grouping(): JsonField<String> = grouping
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The name of the price associated with this line item. */
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -4676,27 +5118,33 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
         /** The start date of the range of time applied for this line item's price. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         /**
          * For complex pricing structures, the line item can be broken down further in
          * `sub_line_items`.
          */
-        @JsonProperty("sub_line_items") @ExcludeMissing fun _subLineItems() = subLineItems
+        @JsonProperty("sub_line_items")
+        @ExcludeMissing
+        fun _subLineItems(): JsonField<List<SubLineItem>> = subLineItems
 
         /** The line amount before any line item-specific discounts or minimums. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
         /**
          * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
          * configured.
          */
-        @JsonProperty("tax_amounts") @ExcludeMissing fun _taxAmounts() = taxAmounts
+        @JsonProperty("tax_amounts")
+        @ExcludeMissing
+        fun _taxAmounts(): JsonField<List<TaxAmount>> = taxAmounts
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4735,22 +5183,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var grouping: JsonField<String> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var subLineItems: JsonField<List<SubLineItem>> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var taxAmounts: JsonField<List<TaxAmount>> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var grouping: JsonField<String>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var price: JsonField<Price>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
+            private var subLineItems: JsonField<MutableList<SubLineItem>>? = null
+            private var subtotal: JsonField<String>? = null
+            private var taxAmounts: JsonField<MutableList<TaxAmount>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4768,9 +5216,9 @@ private constructor(
                 price = lineItem.price
                 quantity = lineItem.quantity
                 startDate = lineItem.startDate
-                subLineItems = lineItem.subLineItems
+                subLineItems = lineItem.subLineItems.map { it.toMutableList() }
                 subtotal = lineItem.subtotal
-                taxAmounts = lineItem.taxAmounts
+                taxAmounts = lineItem.taxAmounts.map { it.toMutableList() }
                 additionalProperties = lineItem.additionalProperties.toMutableMap()
             }
 
@@ -4786,10 +5234,24 @@ private constructor(
             /** The final amount after any discounts or minimums. */
             fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
             /** The end date of the range of time applied for this line item's price. */
             fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
 
@@ -4801,40 +5263,289 @@ private constructor(
              * populated with the key and a value. The `amount` and `subtotal` will be the values
              * for this particular grouping.
              */
-            fun grouping(grouping: String) = grouping(JsonField.of(grouping))
+            fun grouping(grouping: String?) = grouping(JsonField.ofNullable(grouping))
+
+            /**
+             * [DEPRECATED] For configured prices that are split by a grouping key, this will be
+             * populated with the key and a value. The `amount` and `subtotal` will be the values
+             * for this particular grouping.
+             */
+            fun grouping(grouping: Optional<String>) = grouping(grouping.orElse(null))
 
             /**
              * [DEPRECATED] For configured prices that are split by a grouping key, this will be
              * populated with the key and a value. The `amount` and `subtotal` will be the values
              * for this particular grouping.
              */
-            fun grouping(grouping: JsonField<String>) = apply { this.grouping = grouping }
-
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
-
-            fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
-
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
-
-            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
-                this.maximumAmount = maximumAmount
-            }
-
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
-
-            fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
-
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
-
-            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
-                this.minimumAmount = minimumAmount
-            }
-
-            /** The name of the price associated with this line item. */
-            fun name(name: String) = name(JsonField.of(name))
-
-            /** The name of the price associated with this line item. */
-            fun name(name: JsonField<String>) = apply { this.name = name }
+            fun grouping(grouping: JsonField<String>) = apply { this.grouping = grouping }
+
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
+
+            fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
+
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
+
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
+
+            fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
+
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
+
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
+            }
+
+            /** The name of the price associated with this line item. */
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price associated with this line item. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            /**
+             * The Price resource represents a price that can be billed on a subscription, resulting
+             * in a charge on an invoice in the form of an invoice line item. Prices take a quantity
+             * and determine an amount to bill.
+             *
+             * Orb supports a few different pricing models out of the box. Each of these models is
+             * serialized differently in a given Price object. The model_type field determines the
+             * key for the configuration object that is present.
+             *
+             * ## Unit pricing
+             *
+             * With unit pricing, each unit costs a fixed amount.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "unit",
+             *     "unit_config": {
+             *         "unit_amount": "0.50"
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Tiered pricing
+             *
+             * In tiered pricing, the cost of a given unit depends on the tier range that it falls
+             * into, where each tier range is defined by an upper and lower bound. For example, the
+             * first ten units may cost $0.50 each and all units thereafter may cost $0.10 each.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "tiered",
+             *     "tiered_config": {
+             *         "tiers": [
+             *             {
+             *                 "first_unit": 1,
+             *                 "last_unit": 10,
+             *                 "unit_amount": "0.50"
+             *             },
+             *             {
+             *                 "first_unit": 11,
+             *                 "last_unit": null,
+             *                 "unit_amount": "0.10"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * ```
+             *
+             * ## Bulk pricing
+             *
+             * Bulk pricing applies when the number of units determine the cost of all units. For
+             * example, if you've bought less than 10 units, they may each be $0.50 for a total of
+             * $5.00. Once you've bought more than 10 units, all units may now be priced at $0.40
+             * (i.e. 101 units total would be $40.40).
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "bulk",
+             *     "bulk_config": {
+             *         "tiers": [
+             *             {
+             *                 "maximum_units": 10,
+             *                 "unit_amount": "0.50"
+             *             },
+             *             {
+             *                 "maximum_units": 1000,
+             *                 "unit_amount": "0.40"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Package pricing
+             *
+             * Package pricing defines the size or granularity of a unit for billing purposes. For
+             * example, if the package size is set to 5, then 4 units will be billed as 5 and 6
+             * units will be billed at 10.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "package",
+             *     "package_config": {
+             *         "package_amount": "0.80",
+             *         "package_size": 10
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## BPS pricing
+             *
+             * BPS pricing specifies a per-event (e.g. per-payment) rate in one hundredth of a
+             * percent (the number of basis points to charge), as well as a cap per event to assess.
+             * For example, this would allow you to assess a fee of 0.25% on every payment you
+             * process, with a maximum charge of $25 per payment.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "bps",
+             *     "bps_config": {
+             *        "bps": 125,
+             *        "per_unit_maximum": "11.00"
+             *     }
+             *     ...
+             *  }
+             * ```
+             *
+             * ## Bulk BPS pricing
+             *
+             * Bulk BPS pricing specifies BPS parameters in a tiered manner, dependent on the total
+             * quantity across all events. Similar to bulk pricing, the BPS parameters of a given
+             * event depends on the tier range that the billing period falls into. Each tier range
+             * is defined by an upper bound. For example, after $1.5M of payment volume is reached,
+             * each individual payment may have a lower cap or a smaller take-rate.
+             *
+             * ```json
+             *     ...
+             *     "model_type": "bulk_bps",
+             *     "bulk_bps_config": {
+             *         "tiers": [
+             *            {
+             *                 "maximum_amount": "1000000.00",
+             *                 "bps": 125,
+             *                 "per_unit_maximum": "19.00"
+             *            },
+             *           {
+             *                 "maximum_amount": null,
+             *                 "bps": 115,
+             *                 "per_unit_maximum": "4.00"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Tiered BPS pricing
+             *
+             * Tiered BPS pricing specifies BPS parameters in a graduated manner, where an event's
+             * applicable parameter is a function of its marginal addition to the period total.
+             * Similar to tiered pricing, the BPS parameters of a given event depends on the tier
+             * range that it falls into, where each tier range is defined by an upper and lower
+             * bound. For example, the first few payments may have a 0.8 BPS take-rate and all
+             * payments after a specific volume may incur a take-rate of 0.5 BPS each.
+             *
+             * ```json
+             *     ...
+             *     "model_type": "tiered_bps",
+             *     "tiered_bps_config": {
+             *         "tiers": [
+             *            {
+             *                 "minimum_amount": "0",
+             *                 "maximum_amount": "1000000.00",
+             *                 "bps": 125,
+             *                 "per_unit_maximum": "19.00"
+             *            },
+             *           {
+             *                 "minimum_amount": "1000000.00",
+             *                 "maximum_amount": null,
+             *                 "bps": 115,
+             *                 "per_unit_maximum": "4.00"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Matrix pricing
+             *
+             * Matrix pricing defines a set of unit prices in a one or two-dimensional matrix.
+             * `dimensions` defines the two event property values evaluated in this pricing model.
+             * In a one-dimensional matrix, the second value is `null`. Every configuration has a
+             * list of `matrix_values` which give the unit prices for specified property values. In
+             * a one-dimensional matrix, the matrix values will have `dimension_values` where the
+             * second value of the pair is null. If an event does not match any of the dimension
+             * values in the matrix, it will resort to the `default_unit_amount`.
+             *
+             * ```json
+             * {
+             *     "model_type": "matrix"
+             *     "matrix_config": {
+             *         "default_unit_amount": "3.00",
+             *         "dimensions": [
+             *             "cluster_name",
+             *             "region"
+             *         ],
+             *         "matrix_values": [
+             *             {
+             *                 "dimension_values": [
+             *                     "alpha",
+             *                     "west"
+             *                 ],
+             *                 "unit_amount": "2.00"
+             *             },
+             *             ...
+             *         ]
+             *     }
+             * }
+             * ```
+             *
+             * ## Fixed fees
+             *
+             * Fixed fees are prices that are applied independent of usage quantities, and follow
+             * unit pricing. They also have an additional parameter `fixed_price_quantity`. If the
+             * Price represents a fixed cost, this represents the quantity of units applied.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "id": "price_id",
+             *     "model_type": "unit",
+             *     "unit_config": {
+             *        "unit_amount": "2.00"
+             *     },
+             *     "fixed_price_quantity": 3.0
+             *     ...
+             * }
+             * ```
+             */
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5064,7 +5775,7 @@ private constructor(
              * }
              * ```
              */
-            fun price(price: Price) = price(JsonField.of(price))
+            fun price(price: Optional<Price>) = price(price.orElse(null))
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5296,6 +6007,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
 
             fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -5320,7 +6096,24 @@ private constructor(
              * `sub_line_items`.
              */
             fun subLineItems(subLineItems: JsonField<List<SubLineItem>>) = apply {
-                this.subLineItems = subLineItems
+                this.subLineItems = subLineItems.map { it.toMutableList() }
+            }
+
+            /**
+             * For complex pricing structures, the line item can be broken down further in
+             * `sub_line_items`.
+             */
+            fun addSubLineItem(subLineItem: SubLineItem) = apply {
+                subLineItems =
+                    (subLineItems ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(subLineItem)
+                    }
             }
 
             /** The line amount before any line item-specific discounts or minimums. */
@@ -5340,7 +6133,24 @@ private constructor(
              * configured.
              */
             fun taxAmounts(taxAmounts: JsonField<List<TaxAmount>>) = apply {
-                this.taxAmounts = taxAmounts
+                this.taxAmounts = taxAmounts.map { it.toMutableList() }
+            }
+
+            /**
+             * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
+             * configured.
+             */
+            fun addTaxAmount(taxAmount: TaxAmount) = apply {
+                taxAmounts =
+                    (taxAmounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(taxAmount)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -5364,22 +6174,24 @@ private constructor(
 
             fun build(): LineItem =
                 LineItem(
-                    id,
-                    amount,
-                    discount,
-                    endDate,
-                    grouping,
-                    maximum,
-                    maximumAmount,
-                    minimum,
-                    minimumAmount,
-                    name,
-                    price,
-                    quantity,
-                    startDate,
-                    subLineItems.map { it.toImmutable() },
-                    subtotal,
-                    taxAmounts.map { it.toImmutable() },
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(grouping) { "`grouping` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
+                    checkNotNull(subLineItems) { "`subLineItems` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(taxAmounts) { "`taxAmounts` is required but was not set" }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5414,10 +6226,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5442,13 +6256,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -5465,7 +6279,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -5501,8 +6332,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5555,10 +6391,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5583,13 +6421,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -5606,7 +6444,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -5642,8 +6497,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5872,17 +6732,23 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("matrix_config") @ExcludeMissing fun _matrixConfig() = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -5911,12 +6777,12 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var matrixConfig: JsonField<MatrixConfig> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5936,7 +6802,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -5983,12 +6851,14 @@ private constructor(
 
                     fun build(): MatrixSubLineItem =
                         MatrixSubLineItem(
-                            amount,
-                            grouping,
-                            matrixConfig,
-                            name,
-                            quantity,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(matrixConfig) {
+                                "`matrixConfig` is required but was not set"
+                            },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6012,10 +6882,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6040,8 +6910,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6057,7 +6927,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -6086,8 +6959,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6128,7 +7001,7 @@ private constructor(
                     /** The ordered dimension values for this line item. */
                     @JsonProperty("dimension_values")
                     @ExcludeMissing
-                    fun _dimensionValues() = dimensionValues
+                    fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6152,13 +7025,14 @@ private constructor(
 
                     class Builder {
 
-                        private var dimensionValues: JsonField<List<String?>> = JsonMissing.of()
+                        private var dimensionValues: JsonField<MutableList<String?>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
-                            dimensionValues = matrixConfig.dimensionValues
+                            dimensionValues =
+                                matrixConfig.dimensionValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -6168,7 +7042,21 @@ private constructor(
 
                         /** The ordered dimension values for this line item. */
                         fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
-                            this.dimensionValues = dimensionValues
+                            this.dimensionValues = dimensionValues.map { it.toMutableList() }
+                        }
+
+                        /** The ordered dimension values for this line item. */
+                        fun addDimensionValue(dimensionValue: String) = apply {
+                            dimensionValues =
+                                (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimensionValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -6195,7 +7083,10 @@ private constructor(
 
                         fun build(): MatrixConfig =
                             MatrixConfig(
-                                dimensionValues.map { it.toImmutable() },
+                                checkNotNull(dimensionValues) {
+                                        "`dimensionValues` is required but was not set"
+                                    }
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -6329,17 +7220,23 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("tier_config") @ExcludeMissing fun _tierConfig() = tierConfig
+                @JsonProperty("tier_config")
+                @ExcludeMissing
+                fun _tierConfig(): JsonField<TierConfig> = tierConfig
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -6368,12 +7265,12 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var tierConfig: JsonField<TierConfig> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var tierConfig: JsonField<TierConfig>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6393,7 +7290,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -6439,12 +7338,12 @@ private constructor(
 
                     fun build(): TierSubLineItem =
                         TierSubLineItem(
-                            amount,
-                            grouping,
-                            name,
-                            quantity,
-                            tierConfig,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(tierConfig) { "`tierConfig` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6468,10 +7367,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6496,8 +7395,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6513,7 +7412,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -6542,8 +7444,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6590,11 +7492,17 @@ private constructor(
 
                     fun unitAmount(): String = unitAmount.getRequired("unit_amount")
 
-                    @JsonProperty("first_unit") @ExcludeMissing fun _firstUnit() = firstUnit
+                    @JsonProperty("first_unit")
+                    @ExcludeMissing
+                    fun _firstUnit(): JsonField<Double> = firstUnit
 
-                    @JsonProperty("last_unit") @ExcludeMissing fun _lastUnit() = lastUnit
+                    @JsonProperty("last_unit")
+                    @ExcludeMissing
+                    fun _lastUnit(): JsonField<Double> = lastUnit
 
-                    @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6620,9 +7528,9 @@ private constructor(
 
                     class Builder {
 
-                        private var firstUnit: JsonField<Double> = JsonMissing.of()
-                        private var lastUnit: JsonField<Double> = JsonMissing.of()
-                        private var unitAmount: JsonField<String> = JsonMissing.of()
+                        private var firstUnit: JsonField<Double>? = null
+                        private var lastUnit: JsonField<Double>? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6640,7 +7548,15 @@ private constructor(
                             this.firstUnit = firstUnit
                         }
 
-                        fun lastUnit(lastUnit: Double) = lastUnit(JsonField.of(lastUnit))
+                        fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
+
+                        fun lastUnit(lastUnit: Double) = lastUnit(lastUnit as Double?)
+
+                        @Suppress(
+                            "USELESS_CAST"
+                        ) // See https://youtrack.jetbrains.com/issue/KT-74228
+                        fun lastUnit(lastUnit: Optional<Double>) =
+                            lastUnit(lastUnit.orElse(null) as Double?)
 
                         fun lastUnit(lastUnit: JsonField<Double>) = apply {
                             this.lastUnit = lastUnit
@@ -6676,9 +7592,13 @@ private constructor(
 
                         fun build(): TierConfig =
                             TierConfig(
-                                firstUnit,
-                                lastUnit,
-                                unitAmount,
+                                checkNotNull(firstUnit) {
+                                    "`firstUnit` is required but was not set"
+                                },
+                                checkNotNull(lastUnit) { "`lastUnit` is required but was not set" },
+                                checkNotNull(unitAmount) {
+                                    "`unitAmount` is required but was not set"
+                                },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6807,15 +7727,19 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -6843,11 +7767,11 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6866,7 +7790,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -6906,11 +7832,11 @@ private constructor(
 
                     fun build(): OtherSubLineItem =
                         OtherSubLineItem(
-                            amount,
-                            grouping,
-                            name,
-                            quantity,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6934,10 +7860,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6962,8 +7888,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6979,7 +7905,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -7008,8 +7937,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -7132,17 +8061,17 @@ private constructor(
                 Optional.ofNullable(taxRatePercentage.getNullable("tax_rate_percentage"))
 
             /** The amount of additional tax incurred by this tax rate. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
             /** The human-readable description of the applied tax rate. */
             @JsonProperty("tax_rate_description")
             @ExcludeMissing
-            fun _taxRateDescription() = taxRateDescription
+            fun _taxRateDescription(): JsonField<String> = taxRateDescription
 
             /** The tax rate percentage, out of 100. */
             @JsonProperty("tax_rate_percentage")
             @ExcludeMissing
-            fun _taxRatePercentage() = taxRatePercentage
+            fun _taxRatePercentage(): JsonField<String> = taxRatePercentage
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7168,9 +8097,9 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var taxRateDescription: JsonField<String> = JsonMissing.of()
-                private var taxRatePercentage: JsonField<String> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var taxRateDescription: JsonField<String>? = null
+                private var taxRatePercentage: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7197,8 +8126,12 @@ private constructor(
                 }
 
                 /** The tax rate percentage, out of 100. */
-                fun taxRatePercentage(taxRatePercentage: String) =
-                    taxRatePercentage(JsonField.of(taxRatePercentage))
+                fun taxRatePercentage(taxRatePercentage: String?) =
+                    taxRatePercentage(JsonField.ofNullable(taxRatePercentage))
+
+                /** The tax rate percentage, out of 100. */
+                fun taxRatePercentage(taxRatePercentage: Optional<String>) =
+                    taxRatePercentage(taxRatePercentage.orElse(null))
 
                 /** The tax rate percentage, out of 100. */
                 fun taxRatePercentage(taxRatePercentage: JsonField<String>) = apply {
@@ -7229,9 +8162,13 @@ private constructor(
 
                 fun build(): TaxAmount =
                     TaxAmount(
-                        amount,
-                        taxRateDescription,
-                        taxRatePercentage,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(taxRateDescription) {
+                            "`taxRateDescription` is required but was not set"
+                        },
+                        checkNotNull(taxRatePercentage) {
+                            "`taxRatePercentage` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7302,10 +8239,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Maximum amount applied */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7330,13 +8269,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var maximumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximum: Maximum) = apply {
-                appliesToPriceIds = maximum.appliesToPriceIds
+                appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                 maximumAmount = maximum.maximumAmount
                 additionalProperties = maximum.additionalProperties.toMutableMap()
             }
@@ -7353,7 +8292,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this maximum amount applies to. For plan/plan phase maximums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Maximum amount applied */
@@ -7385,8 +8341,11 @@ private constructor(
 
             fun build(): Maximum =
                 Maximum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    maximumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7519,10 +8478,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Minimum amount applied */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7547,13 +8508,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var minimumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimum: Minimum) = apply {
-                appliesToPriceIds = minimum.appliesToPriceIds
+                appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                 minimumAmount = minimum.minimumAmount
                 additionalProperties = minimum.additionalProperties.toMutableMap()
             }
@@ -7570,7 +8531,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this minimum amount applies to. For plan/plan phase minimums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Minimum amount applied */
@@ -7602,8 +8580,11 @@ private constructor(
 
             fun build(): Minimum =
                 Minimum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    minimumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7671,24 +8652,28 @@ private constructor(
         fun succeeded(): Boolean = succeeded.getRequired("succeeded")
 
         /** The ID of the payment attempt. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The amount of the payment attempt. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The time at which the payment attempt was created. */
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         /** The payment provider that attempted to collect the payment. */
-        @JsonProperty("payment_provider") @ExcludeMissing fun _paymentProvider() = paymentProvider
+        @JsonProperty("payment_provider")
+        @ExcludeMissing
+        fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
         /** The ID of the payment attempt in the payment provider. */
         @JsonProperty("payment_provider_id")
         @ExcludeMissing
-        fun _paymentProviderId() = paymentProviderId
+        fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
         /** Whether the payment attempt succeeded. */
-        @JsonProperty("succeeded") @ExcludeMissing fun _succeeded() = succeeded
+        @JsonProperty("succeeded") @ExcludeMissing fun _succeeded(): JsonField<Boolean> = succeeded
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7717,12 +8702,12 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
-            private var paymentProviderId: JsonField<String> = JsonMissing.of()
-            private var succeeded: JsonField<Boolean> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<String>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var paymentProvider: JsonField<PaymentProvider>? = null
+            private var paymentProviderId: JsonField<String>? = null
+            private var succeeded: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -7757,8 +8742,12 @@ private constructor(
             }
 
             /** The payment provider that attempted to collect the payment. */
-            fun paymentProvider(paymentProvider: PaymentProvider) =
-                paymentProvider(JsonField.of(paymentProvider))
+            fun paymentProvider(paymentProvider: PaymentProvider?) =
+                paymentProvider(JsonField.ofNullable(paymentProvider))
+
+            /** The payment provider that attempted to collect the payment. */
+            fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
+                paymentProvider(paymentProvider.orElse(null))
 
             /** The payment provider that attempted to collect the payment. */
             fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
@@ -7766,8 +8755,12 @@ private constructor(
             }
 
             /** The ID of the payment attempt in the payment provider. */
-            fun paymentProviderId(paymentProviderId: String) =
-                paymentProviderId(JsonField.of(paymentProviderId))
+            fun paymentProviderId(paymentProviderId: String?) =
+                paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+            /** The ID of the payment attempt in the payment provider. */
+            fun paymentProviderId(paymentProviderId: Optional<String>) =
+                paymentProviderId(paymentProviderId.orElse(null))
 
             /** The ID of the payment attempt in the payment provider. */
             fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
@@ -7801,12 +8794,16 @@ private constructor(
 
             fun build(): PaymentAttempt =
                 PaymentAttempt(
-                    id,
-                    amount,
-                    createdAt,
-                    paymentProvider,
-                    paymentProviderId,
-                    succeeded,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(paymentProvider) {
+                        "`paymentProvider` is required but was not set"
+                    },
+                    checkNotNull(paymentProviderId) {
+                        "`paymentProviderId` is required but was not set"
+                    },
+                    checkNotNull(succeeded) { "`succeeded` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7919,17 +8916,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7958,12 +8957,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -7977,27 +8976,39 @@ private constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -8022,12 +9033,12 @@ private constructor(
 
             fun build(): ShippingAddress =
                 ShippingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -8136,7 +9147,7 @@ private constructor(
 
         fun id(): String = id.getRequired("id")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -8160,7 +9171,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -8192,7 +9203,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Subscription = Subscription(id, additionalProperties.toImmutable())
+            fun build(): Subscription =
+                Subscription(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceCreateParams.kt
index bd815815..b3b87620 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceCreateParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -21,6 +22,7 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/** This endpoint is used to create a one-off invoice for a customer. */
 class InvoiceCreateParams
 constructor(
     private val body: InvoiceCreateBody,
@@ -77,12 +79,61 @@ constructor(
      */
     fun willAutoIssue(): Optional<Boolean> = body.willAutoIssue()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** An ISO 4217 currency string. Must be the same as the customer's currency if it is set. */
+    fun _currency(): JsonField<String> = body._currency()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set to the
+     * current time in the customer's timezone.
+     */
+    fun _invoiceDate(): JsonField<OffsetDateTime> = body._invoiceDate()
+
+    fun _lineItems(): JsonField<List<LineItem>> = body._lineItems()
+
+    /**
+     * Determines the difference between the invoice issue date for subscription invoices as the
+     * date that they are due. A value of '0' here represents that the invoice is due on issue,
+     * whereas a value of 30 represents that the customer has 30 days to pay the invoice.
+     */
+    fun _netTerms(): JsonField<Long> = body._netTerms()
+
+    /**
+     * The id of the `Customer` to create this invoice for. One of `customer_id` and
+     * `external_customer_id` are required.
+     */
+    fun _customerId(): JsonField<String> = body._customerId()
+
+    /** An optional discount to attach to the invoice. */
+    fun _discount(): JsonField<Discount> = body._discount()
+
+    /**
+     * The `external_customer_id` of the `Customer` to create this invoice for. One of `customer_id`
+     * and `external_customer_id` are required.
+     */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /** An optional memo to attach to the invoice. */
+    fun _memo(): JsonField<String> = body._memo()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /**
+     * When true, this invoice will automatically be issued upon creation. When false, the resulting
+     * invoice will require manual review to issue. Defaulted to false.
+     */
+    fun _willAutoIssue(): JsonField<Boolean> = body._willAutoIssue()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): InvoiceCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -93,16 +144,36 @@ constructor(
     class InvoiceCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("invoice_date") private val invoiceDate: OffsetDateTime,
-        @JsonProperty("line_items") private val lineItems: List<LineItem>,
-        @JsonProperty("net_terms") private val netTerms: Long,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("discount") private val discount: Discount?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("memo") private val memo: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("will_auto_issue") private val willAutoIssue: Boolean?,
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoice_date")
+        @ExcludeMissing
+        private val invoiceDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("line_items")
+        @ExcludeMissing
+        private val lineItems: JsonField<List<LineItem>> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("discount")
+        @ExcludeMissing
+        private val discount: JsonField<Discount> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("memo")
+        @ExcludeMissing
+        private val memo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("will_auto_issue")
+        @ExcludeMissing
+        private val willAutoIssue: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -110,61 +181,140 @@ constructor(
         /**
          * An ISO 4217 currency string. Must be the same as the customer's currency if it is set.
          */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
+
+        /**
+         * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set to
+         * the current time in the customer's timezone.
+         */
+        fun invoiceDate(): OffsetDateTime = invoiceDate.getRequired("invoice_date")
+
+        fun lineItems(): List<LineItem> = lineItems.getRequired("line_items")
+
+        /**
+         * Determines the difference between the invoice issue date for subscription invoices as the
+         * date that they are due. A value of '0' here represents that the invoice is due on issue,
+         * whereas a value of 30 represents that the customer has 30 days to pay the invoice.
+         */
+        fun netTerms(): Long = netTerms.getRequired("net_terms")
+
+        /**
+         * The id of the `Customer` to create this invoice for. One of `customer_id` and
+         * `external_customer_id` are required.
+         */
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /** An optional discount to attach to the invoice. */
+        fun discount(): Optional<Discount> = Optional.ofNullable(discount.getNullable("discount"))
+
+        /**
+         * The `external_customer_id` of the `Customer` to create this invoice for. One of
+         * `customer_id` and `external_customer_id` are required.
+         */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /** An optional memo to attach to the invoice. */
+        fun memo(): Optional<String> = Optional.ofNullable(memo.getNullable("memo"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * When true, this invoice will automatically be issued upon creation. When false, the
+         * resulting invoice will require manual review to issue. Defaulted to false.
+         */
+        fun willAutoIssue(): Optional<Boolean> =
+            Optional.ofNullable(willAutoIssue.getNullable("will_auto_issue"))
+
+        /**
+         * An ISO 4217 currency string. Must be the same as the customer's currency if it is set.
+         */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /**
          * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set to
          * the current time in the customer's timezone.
          */
-        @JsonProperty("invoice_date") fun invoiceDate(): OffsetDateTime = invoiceDate
+        @JsonProperty("invoice_date")
+        @ExcludeMissing
+        fun _invoiceDate(): JsonField<OffsetDateTime> = invoiceDate
 
-        @JsonProperty("line_items") fun lineItems(): List<LineItem> = lineItems
+        @JsonProperty("line_items")
+        @ExcludeMissing
+        fun _lineItems(): JsonField<List<LineItem>> = lineItems
 
         /**
          * Determines the difference between the invoice issue date for subscription invoices as the
          * date that they are due. A value of '0' here represents that the invoice is due on issue,
          * whereas a value of 30 represents that the customer has 30 days to pay the invoice.
          */
-        @JsonProperty("net_terms") fun netTerms(): Long = netTerms
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /**
          * The id of the `Customer` to create this invoice for. One of `customer_id` and
          * `external_customer_id` are required.
          */
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /** An optional discount to attach to the invoice. */
-        @JsonProperty("discount") fun discount(): Optional<Discount> = Optional.ofNullable(discount)
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
         /**
          * The `external_customer_id` of the `Customer` to create this invoice for. One of
          * `customer_id` and `external_customer_id` are required.
          */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /** An optional memo to attach to the invoice. */
-        @JsonProperty("memo") fun memo(): Optional<String> = Optional.ofNullable(memo)
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * When true, this invoice will automatically be issued upon creation. When false, the
          * resulting invoice will require manual review to issue. Defaulted to false.
          */
         @JsonProperty("will_auto_issue")
-        fun willAutoIssue(): Optional<Boolean> = Optional.ofNullable(willAutoIssue)
+        @ExcludeMissing
+        fun _willAutoIssue(): JsonField<Boolean> = willAutoIssue
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceCreateBody = apply {
+            if (!validated) {
+                currency()
+                invoiceDate()
+                lineItems().forEach { it.validate() }
+                netTerms()
+                customerId()
+                discount()
+                externalCustomerId()
+                memo()
+                metadata().map { it.validate() }
+                willAutoIssue()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -174,23 +324,23 @@ constructor(
 
         class Builder {
 
-            private var currency: String? = null
-            private var invoiceDate: OffsetDateTime? = null
-            private var lineItems: MutableList<LineItem>? = null
-            private var netTerms: Long? = null
-            private var customerId: String? = null
-            private var discount: Discount? = null
-            private var externalCustomerId: String? = null
-            private var memo: String? = null
-            private var metadata: Metadata? = null
-            private var willAutoIssue: Boolean? = null
+            private var currency: JsonField<String>? = null
+            private var invoiceDate: JsonField<OffsetDateTime>? = null
+            private var lineItems: JsonField<MutableList<LineItem>>? = null
+            private var netTerms: JsonField<Long>? = null
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var discount: JsonField<Discount> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var memo: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var willAutoIssue: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(invoiceCreateBody: InvoiceCreateBody) = apply {
                 currency = invoiceCreateBody.currency
                 invoiceDate = invoiceCreateBody.invoiceDate
-                lineItems = invoiceCreateBody.lineItems.toMutableList()
+                lineItems = invoiceCreateBody.lineItems.map { it.toMutableList() }
                 netTerms = invoiceCreateBody.netTerms
                 customerId = invoiceCreateBody.customerId
                 discount = invoiceCreateBody.discount
@@ -205,20 +355,45 @@ constructor(
              * An ISO 4217 currency string. Must be the same as the customer's currency if it is
              * set.
              */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /**
+             * An ISO 4217 currency string. Must be the same as the customer's currency if it is
+             * set.
+             */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /**
              * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set
              * to the current time in the customer's timezone.
              */
-            fun invoiceDate(invoiceDate: OffsetDateTime) = apply { this.invoiceDate = invoiceDate }
+            fun invoiceDate(invoiceDate: OffsetDateTime) = invoiceDate(JsonField.of(invoiceDate))
+
+            /**
+             * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set
+             * to the current time in the customer's timezone.
+             */
+            fun invoiceDate(invoiceDate: JsonField<OffsetDateTime>) = apply {
+                this.invoiceDate = invoiceDate
+            }
 
-            fun lineItems(lineItems: List<LineItem>) = apply {
-                this.lineItems = lineItems.toMutableList()
+            fun lineItems(lineItems: List<LineItem>) = lineItems(JsonField.of(lineItems))
+
+            fun lineItems(lineItems: JsonField<List<LineItem>>) = apply {
+                this.lineItems = lineItems.map { it.toMutableList() }
             }
 
             fun addLineItem(lineItem: LineItem) = apply {
-                lineItems = (lineItems ?: mutableListOf()).apply { add(lineItem) }
+                lineItems =
+                    (lineItems ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(lineItem)
+                    }
             }
 
             /**
@@ -227,13 +402,21 @@ constructor(
              * issue, whereas a value of 30 represents that the customer has 30 days to pay the
              * invoice.
              */
-            fun netTerms(netTerms: Long) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+
+            /**
+             * Determines the difference between the invoice issue date for subscription invoices as
+             * the date that they are due. A value of '0' here represents that the invoice is due on
+             * issue, whereas a value of 30 represents that the customer has 30 days to pay the
+             * invoice.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
             /**
              * The id of the `Customer` to create this invoice for. One of `customer_id` and
              * `external_customer_id` are required.
              */
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             /**
              * The id of the `Customer` to create this invoice for. One of `customer_id` and
@@ -241,35 +424,39 @@ constructor(
              */
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            /**
+             * The id of the `Customer` to create this invoice for. One of `customer_id` and
+             * `external_customer_id` are required.
+             */
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /** An optional discount to attach to the invoice. */
-            fun discount(discount: Discount?) = apply { this.discount = discount }
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
 
             /** An optional discount to attach to the invoice. */
             fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
-            fun discount(percentageDiscount: PercentageDiscount) = apply {
-                this.discount = Discount.ofPercentageDiscount(percentageDiscount)
-            }
+            /** An optional discount to attach to the invoice. */
+            fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun discount(trialDiscount: TrialDiscount) = apply {
-                this.discount = Discount.ofTrialDiscount(trialDiscount)
-            }
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
 
-            fun discount(usageDiscount: Discount.UsageDiscount) = apply {
-                this.discount = Discount.ofUsageDiscount(usageDiscount)
-            }
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
 
-            fun discount(amountDiscount: AmountDiscount) = apply {
-                this.discount = Discount.ofAmountDiscount(amountDiscount)
-            }
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
 
             /**
              * The `external_customer_id` of the `Customer` to create this invoice for. One of
              * `customer_id` and `external_customer_id` are required.
              */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /**
              * The `external_customer_id` of the `Customer` to create this invoice for. One of
@@ -278,18 +465,29 @@ constructor(
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /**
+             * The `external_customer_id` of the `Customer` to create this invoice for. One of
+             * `customer_id` and `external_customer_id` are required.
+             */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             /** An optional memo to attach to the invoice. */
-            fun memo(memo: String?) = apply { this.memo = memo }
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
 
             /** An optional memo to attach to the invoice. */
             fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
+            /** An optional memo to attach to the invoice. */
+            fun memo(memo: JsonField<String>) = apply { this.memo = memo }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -299,26 +497,25 @@ constructor(
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
             /**
-             * When true, this invoice will automatically be issued upon creation. When false, the
-             * resulting invoice will require manual review to issue. Defaulted to false.
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
              */
-            fun willAutoIssue(willAutoIssue: Boolean?) = apply {
-                this.willAutoIssue = willAutoIssue
-            }
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
             /**
              * When true, this invoice will automatically be issued upon creation. When false, the
              * resulting invoice will require manual review to issue. Defaulted to false.
              */
-            fun willAutoIssue(willAutoIssue: Boolean) = willAutoIssue(willAutoIssue as Boolean?)
+            fun willAutoIssue(willAutoIssue: Boolean) = willAutoIssue(JsonField.of(willAutoIssue))
 
             /**
              * When true, this invoice will automatically be issued upon creation. When false, the
              * resulting invoice will require manual review to issue. Defaulted to false.
              */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun willAutoIssue(willAutoIssue: Optional<Boolean>) =
-                willAutoIssue(willAutoIssue.orElse(null) as Boolean?)
+            fun willAutoIssue(willAutoIssue: JsonField<Boolean>) = apply {
+                this.willAutoIssue = willAutoIssue
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -344,7 +541,7 @@ constructor(
                     checkNotNull(currency) { "`currency` is required but was not set" },
                     checkNotNull(invoiceDate) { "`invoiceDate` is required but was not set" },
                     checkNotNull(lineItems) { "`lineItems` is required but was not set" }
-                        .toImmutable(),
+                        .map { it.toImmutable() },
                     checkNotNull(netTerms) { "`netTerms` is required but was not set" },
                     customerId,
                     discount,
@@ -400,14 +597,29 @@ constructor(
          */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /**
+         * An ISO 4217 currency string. Must be the same as the customer's currency if it is set.
+         */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         /**
          * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set to
          * the current time in the customer's timezone.
          */
         fun invoiceDate(invoiceDate: OffsetDateTime) = apply { body.invoiceDate(invoiceDate) }
 
+        /**
+         * Optional invoice date to set. Must be in the past, if not set, `invoice_date` is set to
+         * the current time in the customer's timezone.
+         */
+        fun invoiceDate(invoiceDate: JsonField<OffsetDateTime>) = apply {
+            body.invoiceDate(invoiceDate)
+        }
+
         fun lineItems(lineItems: List<LineItem>) = apply { body.lineItems(lineItems) }
 
+        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply { body.lineItems(lineItems) }
+
         fun addLineItem(lineItem: LineItem) = apply { body.addLineItem(lineItem) }
 
         /**
@@ -417,6 +629,13 @@ constructor(
          */
         fun netTerms(netTerms: Long) = apply { body.netTerms(netTerms) }
 
+        /**
+         * Determines the difference between the invoice issue date for subscription invoices as the
+         * date that they are due. A value of '0' here represents that the invoice is due on issue,
+         * whereas a value of 30 represents that the customer has 30 days to pay the invoice.
+         */
+        fun netTerms(netTerms: JsonField<Long>) = apply { body.netTerms(netTerms) }
+
         /**
          * The id of the `Customer` to create this invoice for. One of `customer_id` and
          * `external_customer_id` are required.
@@ -429,12 +648,21 @@ constructor(
          */
         fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+        /**
+         * The id of the `Customer` to create this invoice for. One of `customer_id` and
+         * `external_customer_id` are required.
+         */
+        fun customerId(customerId: JsonField<String>) = apply { body.customerId(customerId) }
+
         /** An optional discount to attach to the invoice. */
         fun discount(discount: Discount?) = apply { body.discount(discount) }
 
         /** An optional discount to attach to the invoice. */
         fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
+        /** An optional discount to attach to the invoice. */
+        fun discount(discount: JsonField<Discount>) = apply { body.discount(discount) }
+
         fun discount(percentageDiscount: PercentageDiscount) = apply {
             body.discount(percentageDiscount)
         }
@@ -460,12 +688,23 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /**
+         * The `external_customer_id` of the `Customer` to create this invoice for. One of
+         * `customer_id` and `external_customer_id` are required.
+         */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         /** An optional memo to attach to the invoice. */
         fun memo(memo: String?) = apply { body.memo(memo) }
 
         /** An optional memo to attach to the invoice. */
         fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
+        /** An optional memo to attach to the invoice. */
+        fun memo(memo: JsonField<String>) = apply { body.memo(memo) }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -481,24 +720,44 @@ constructor(
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
         /**
-         * When true, this invoice will automatically be issued upon creation. When false, the
-         * resulting invoice will require manual review to issue. Defaulted to false.
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
          */
-        fun willAutoIssue(willAutoIssue: Boolean?) = apply { body.willAutoIssue(willAutoIssue) }
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
 
         /**
          * When true, this invoice will automatically be issued upon creation. When false, the
          * resulting invoice will require manual review to issue. Defaulted to false.
          */
-        fun willAutoIssue(willAutoIssue: Boolean) = willAutoIssue(willAutoIssue as Boolean?)
+        fun willAutoIssue(willAutoIssue: Boolean) = apply { body.willAutoIssue(willAutoIssue) }
 
         /**
          * When true, this invoice will automatically be issued upon creation. When false, the
          * resulting invoice will require manual review to issue. Defaulted to false.
          */
-        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-        fun willAutoIssue(willAutoIssue: Optional<Boolean>) =
-            willAutoIssue(willAutoIssue.orElse(null) as Boolean?)
+        fun willAutoIssue(willAutoIssue: JsonField<Boolean>) = apply {
+            body.willAutoIssue(willAutoIssue)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -598,25 +857,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): InvoiceCreateParams =
             InvoiceCreateParams(
                 body.build(),
@@ -629,39 +869,92 @@ constructor(
     class LineItem
     @JsonCreator
     private constructor(
-        @JsonProperty("end_date") private val endDate: LocalDate,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("quantity") private val quantity: Double,
-        @JsonProperty("start_date") private val startDate: LocalDate,
-        @JsonProperty("unit_config") private val unitConfig: UnitConfig,
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("quantity")
+        @ExcludeMissing
+        private val quantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("unit_config")
+        @ExcludeMissing
+        private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** A date string to specify the line item's end date in the customer's timezone. */
-        @JsonProperty("end_date") fun endDate(): LocalDate = endDate
+        fun endDate(): LocalDate = endDate.getRequired("end_date")
 
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        fun itemId(): String = itemId.getRequired("item_id")
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        fun modelType(): ModelType = modelType.getRequired("model_type")
 
         /** The name of the line item. */
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
 
         /** The number of units on the line item */
-        @JsonProperty("quantity") fun quantity(): Double = quantity
+        fun quantity(): Double = quantity.getRequired("quantity")
 
         /** A date string to specify the line item's start date in the customer's timezone. */
-        @JsonProperty("start_date") fun startDate(): LocalDate = startDate
+        fun startDate(): LocalDate = startDate.getRequired("start_date")
 
-        @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+        fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+        /** A date string to specify the line item's end date in the customer's timezone. */
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<LocalDate> = endDate
+
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
+
+        /** The name of the line item. */
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+        /** The number of units on the line item */
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
+
+        /** A date string to specify the line item's start date in the customer's timezone. */
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<LocalDate> = startDate
+
+        @JsonProperty("unit_config")
+        @ExcludeMissing
+        fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): LineItem = apply {
+            if (!validated) {
+                endDate()
+                itemId()
+                modelType()
+                name()
+                quantity()
+                startDate()
+                unitConfig().validate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -671,13 +964,13 @@ constructor(
 
         class Builder {
 
-            private var endDate: LocalDate? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var quantity: Double? = null
-            private var startDate: LocalDate? = null
-            private var unitConfig: UnitConfig? = null
+            private var endDate: JsonField<LocalDate>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<LocalDate>? = null
+            private var unitConfig: JsonField<UnitConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -693,22 +986,42 @@ constructor(
             }
 
             /** A date string to specify the line item's end date in the customer's timezone. */
-            fun endDate(endDate: LocalDate) = apply { this.endDate = endDate }
+            fun endDate(endDate: LocalDate) = endDate(JsonField.of(endDate))
+
+            /** A date string to specify the line item's end date in the customer's timezone. */
+            fun endDate(endDate: JsonField<LocalDate>) = apply { this.endDate = endDate }
+
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the line item. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the line item. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /** The number of units on the line item */
-            fun quantity(quantity: Double) = apply { this.quantity = quantity }
+            fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
+
+            /** The number of units on the line item */
+            fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
+
+            /** A date string to specify the line item's start date in the customer's timezone. */
+            fun startDate(startDate: LocalDate) = startDate(JsonField.of(startDate))
 
             /** A date string to specify the line item's start date in the customer's timezone. */
-            fun startDate(startDate: LocalDate) = apply { this.startDate = startDate }
+            fun startDate(startDate: JsonField<LocalDate>) = apply { this.startDate = startDate }
 
-            fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+            fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
+
+            fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                this.unitConfig = unitConfig
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -797,18 +1110,34 @@ constructor(
         class UnitConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("unit_amount") private val unitAmount: String,
+            @JsonProperty("unit_amount")
+            @ExcludeMissing
+            private val unitAmount: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Rate per unit of usage */
-            @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+            fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+            /** Rate per unit of usage */
+            @JsonProperty("unit_amount")
+            @ExcludeMissing
+            fun _unitAmount(): JsonField<String> = unitAmount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): UnitConfig = apply {
+                if (!validated) {
+                    unitAmount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -818,7 +1147,7 @@ constructor(
 
             class Builder {
 
-                private var unitAmount: String? = null
+                private var unitAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -828,7 +1157,12 @@ constructor(
                 }
 
                 /** Rate per unit of usage */
-                fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                /** Rate per unit of usage */
+                fun unitAmount(unitAmount: JsonField<String>) = apply {
+                    this.unitAmount = unitAmount
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -912,6 +1246,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchParams.kt
index 66fbc147..87645db2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchParams.kt
@@ -7,6 +7,9 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch an [`Invoice`](../guides/concepts#invoice) given an identifier.
+ */
 class InvoiceFetchParams
 constructor(
     private val invoiceId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingParams.kt
index cdcc5670..4e9598bb 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingParams.kt
@@ -7,6 +7,10 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint can be used to fetch the upcoming [invoice](../guides/concepts#invoice) for the
+ * current billing period given a subscription.
+ */
 class InvoiceFetchUpcomingParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingResponse.kt
index 18f19f9d..047f4593 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceFetchUpcomingResponse.kt
@@ -289,6 +289,12 @@ private constructor(
     fun customerTaxId(): Optional<CustomerTaxId> =
         Optional.ofNullable(customerTaxId.getNullable("customer_tax_id"))
 
+    /**
+     * This field is deprecated in favor of `discounts`. If a `discounts` list is provided, the
+     * first discount in the list will be returned. If the list is empty, `None` will be returned.
+     */
+    @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonValue = discount
+
     fun discounts(): List<InvoiceLevelDiscount> = discounts.getRequired("discounts")
 
     /** When the invoice payment is due. */
@@ -420,32 +426,41 @@ private constructor(
      */
     fun willAutoIssue(): Boolean = willAutoIssue.getRequired("will_auto_issue")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * This is the final amount required to be charged to the customer and reflects the application
      * of the customer balance to the `total` of the invoice.
      */
-    @JsonProperty("amount_due") @ExcludeMissing fun _amountDue() = amountDue
+    @JsonProperty("amount_due") @ExcludeMissing fun _amountDue(): JsonField<String> = amountDue
 
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<AutoCollection> = autoCollection
 
-    @JsonProperty("billing_address") @ExcludeMissing fun _billingAddress() = billingAddress
+    @JsonProperty("billing_address")
+    @ExcludeMissing
+    fun _billingAddress(): JsonField<BillingAddress> = billingAddress
 
     /** The creation time of the resource in Orb. */
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /** A list of credit notes associated with the invoice */
-    @JsonProperty("credit_notes") @ExcludeMissing fun _creditNotes() = creditNotes
+    @JsonProperty("credit_notes")
+    @ExcludeMissing
+    fun _creditNotes(): JsonField<List<CreditNote>> = creditNotes
 
     /** An ISO 4217 currency string or `credits` */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     @JsonProperty("customer_balance_transactions")
     @ExcludeMissing
-    fun _customerBalanceTransactions() = customerBalanceTransactions
+    fun _customerBalanceTransactions(): JsonField<List<CustomerBalanceTransaction>> =
+        customerBalanceTransactions
 
     /**
      * Tax IDs are commonly required to be displayed on customer invoices, which are added to the
@@ -553,18 +568,16 @@ private constructor(
      * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
      * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
      */
-    @JsonProperty("customer_tax_id") @ExcludeMissing fun _customerTaxId() = customerTaxId
-
-    /**
-     * This field is deprecated in favor of `discounts`. If a `discounts` list is provided, the
-     * first discount in the list will be returned. If the list is empty, `None` will be returned.
-     */
-    @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+    @JsonProperty("customer_tax_id")
+    @ExcludeMissing
+    fun _customerTaxId(): JsonField<CustomerTaxId> = customerTaxId
 
-    @JsonProperty("discounts") @ExcludeMissing fun _discounts() = discounts
+    @JsonProperty("discounts")
+    @ExcludeMissing
+    fun _discounts(): JsonField<List<InvoiceLevelDiscount>> = discounts
 
     /** When the invoice payment is due. */
-    @JsonProperty("due_date") @ExcludeMissing fun _dueDate() = dueDate
+    @JsonProperty("due_date") @ExcludeMissing fun _dueDate(): JsonField<OffsetDateTime> = dueDate
 
     /**
      * If the invoice has a status of `draft`, this will be the time that the invoice will be
@@ -573,113 +586,145 @@ private constructor(
      */
     @JsonProperty("eligible_to_issue_at")
     @ExcludeMissing
-    fun _eligibleToIssueAt() = eligibleToIssueAt
+    fun _eligibleToIssueAt(): JsonField<OffsetDateTime> = eligibleToIssueAt
 
     /**
      * A URL for the customer-facing invoice portal. This URL expires 30 days after the invoice's
      * due date, or 60 days after being re-generated through the UI.
      */
-    @JsonProperty("hosted_invoice_url") @ExcludeMissing fun _hostedInvoiceUrl() = hostedInvoiceUrl
+    @JsonProperty("hosted_invoice_url")
+    @ExcludeMissing
+    fun _hostedInvoiceUrl(): JsonField<String> = hostedInvoiceUrl
 
     /**
      * Automatically generated invoice number to help track and reconcile invoices. Invoice numbers
      * have a prefix such as `RFOBWG`. These can be sequential per account or customer.
      */
-    @JsonProperty("invoice_number") @ExcludeMissing fun _invoiceNumber() = invoiceNumber
+    @JsonProperty("invoice_number")
+    @ExcludeMissing
+    fun _invoiceNumber(): JsonField<String> = invoiceNumber
 
     /** The link to download the PDF representation of the `Invoice`. */
-    @JsonProperty("invoice_pdf") @ExcludeMissing fun _invoicePdf() = invoicePdf
+    @JsonProperty("invoice_pdf") @ExcludeMissing fun _invoicePdf(): JsonField<String> = invoicePdf
 
-    @JsonProperty("invoice_source") @ExcludeMissing fun _invoiceSource() = invoiceSource
+    @JsonProperty("invoice_source")
+    @ExcludeMissing
+    fun _invoiceSource(): JsonField<InvoiceSource> = invoiceSource
 
     /**
      * If the invoice failed to issue, this will be the last time it failed to issue (even if it is
      * now in a different state.)
      */
-    @JsonProperty("issue_failed_at") @ExcludeMissing fun _issueFailedAt() = issueFailedAt
+    @JsonProperty("issue_failed_at")
+    @ExcludeMissing
+    fun _issueFailedAt(): JsonField<OffsetDateTime> = issueFailedAt
 
     /**
      * If the invoice has been issued, this will be the time it transitioned to `issued` (even if it
      * is now in a different state.)
      */
-    @JsonProperty("issued_at") @ExcludeMissing fun _issuedAt() = issuedAt
+    @JsonProperty("issued_at") @ExcludeMissing fun _issuedAt(): JsonField<OffsetDateTime> = issuedAt
 
     /** The breakdown of prices in this invoice. */
-    @JsonProperty("line_items") @ExcludeMissing fun _lineItems() = lineItems
+    @JsonProperty("line_items")
+    @ExcludeMissing
+    fun _lineItems(): JsonField<List<LineItem>> = lineItems
 
-    @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+    @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-    @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+    @JsonProperty("maximum_amount")
+    @ExcludeMissing
+    fun _maximumAmount(): JsonField<String> = maximumAmount
 
     /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
-    @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+    @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-    @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+    @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-    @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+    @JsonProperty("minimum_amount")
+    @ExcludeMissing
+    fun _minimumAmount(): JsonField<String> = minimumAmount
 
     /** If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid. */
-    @JsonProperty("paid_at") @ExcludeMissing fun _paidAt() = paidAt
+    @JsonProperty("paid_at") @ExcludeMissing fun _paidAt(): JsonField<OffsetDateTime> = paidAt
 
     /** A list of payment attempts associated with the invoice */
-    @JsonProperty("payment_attempts") @ExcludeMissing fun _paymentAttempts() = paymentAttempts
+    @JsonProperty("payment_attempts")
+    @ExcludeMissing
+    fun _paymentAttempts(): JsonField<List<PaymentAttempt>> = paymentAttempts
 
     /**
      * If payment was attempted on this invoice but failed, this will be the time of the most recent
      * attempt.
      */
-    @JsonProperty("payment_failed_at") @ExcludeMissing fun _paymentFailedAt() = paymentFailedAt
+    @JsonProperty("payment_failed_at")
+    @ExcludeMissing
+    fun _paymentFailedAt(): JsonField<OffsetDateTime> = paymentFailedAt
 
     /**
      * If payment was attempted on this invoice, this will be the start time of the most recent
      * attempt. This field is especially useful for delayed-notification payment mechanisms (like
      * bank transfers), where payment can take 3 days or more.
      */
-    @JsonProperty("payment_started_at") @ExcludeMissing fun _paymentStartedAt() = paymentStartedAt
+    @JsonProperty("payment_started_at")
+    @ExcludeMissing
+    fun _paymentStartedAt(): JsonField<OffsetDateTime> = paymentStartedAt
 
     /**
      * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to be
      * issued.
      */
-    @JsonProperty("scheduled_issue_at") @ExcludeMissing fun _scheduledIssueAt() = scheduledIssueAt
+    @JsonProperty("scheduled_issue_at")
+    @ExcludeMissing
+    fun _scheduledIssueAt(): JsonField<OffsetDateTime> = scheduledIssueAt
 
-    @JsonProperty("shipping_address") @ExcludeMissing fun _shippingAddress() = shippingAddress
+    @JsonProperty("shipping_address")
+    @ExcludeMissing
+    fun _shippingAddress(): JsonField<ShippingAddress> = shippingAddress
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("subscription") @ExcludeMissing fun _subscription() = subscription
+    @JsonProperty("subscription")
+    @ExcludeMissing
+    fun _subscription(): JsonField<Subscription> = subscription
 
     /** The total before any discounts and minimums are applied. */
-    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
     /**
      * If the invoice failed to sync, this will be the last time an external invoicing provider sync
      * was attempted. This field will always be `null` for invoices using Orb Invoicing.
      */
-    @JsonProperty("sync_failed_at") @ExcludeMissing fun _syncFailedAt() = syncFailedAt
+    @JsonProperty("sync_failed_at")
+    @ExcludeMissing
+    fun _syncFailedAt(): JsonField<OffsetDateTime> = syncFailedAt
 
     /** The scheduled date of the invoice */
-    @JsonProperty("target_date") @ExcludeMissing fun _targetDate() = targetDate
+    @JsonProperty("target_date")
+    @ExcludeMissing
+    fun _targetDate(): JsonField<OffsetDateTime> = targetDate
 
     /** The total after any minimums and discounts have been applied. */
-    @JsonProperty("total") @ExcludeMissing fun _total() = total
+    @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
     /**
      * If the invoice has a status of `void`, this gives a timestamp when the invoice was voided.
      */
-    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt() = voidedAt
+    @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt(): JsonField<OffsetDateTime> = voidedAt
 
     /**
      * This is true if the invoice will be automatically issued in the future, and false otherwise.
      */
-    @JsonProperty("will_auto_issue") @ExcludeMissing fun _willAutoIssue() = willAutoIssue
+    @JsonProperty("will_auto_issue")
+    @ExcludeMissing
+    fun _willAutoIssue(): JsonField<Boolean> = willAutoIssue
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -742,48 +787,49 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amountDue: JsonField<String> = JsonMissing.of()
-        private var autoCollection: JsonField<AutoCollection> = JsonMissing.of()
-        private var billingAddress: JsonField<BillingAddress> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var creditNotes: JsonField<List<CreditNote>> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var customerBalanceTransactions: JsonField<List<CustomerBalanceTransaction>> =
-            JsonMissing.of()
-        private var customerTaxId: JsonField<CustomerTaxId> = JsonMissing.of()
-        private var discount: JsonValue = JsonMissing.of()
-        private var discounts: JsonField<List<InvoiceLevelDiscount>> = JsonMissing.of()
-        private var dueDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var eligibleToIssueAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var hostedInvoiceUrl: JsonField<String> = JsonMissing.of()
-        private var invoiceNumber: JsonField<String> = JsonMissing.of()
-        private var invoicePdf: JsonField<String> = JsonMissing.of()
-        private var invoiceSource: JsonField<InvoiceSource> = JsonMissing.of()
-        private var issueFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var issuedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var lineItems: JsonField<List<LineItem>> = JsonMissing.of()
-        private var maximum: JsonField<Maximum> = JsonMissing.of()
-        private var maximumAmount: JsonField<String> = JsonMissing.of()
-        private var memo: JsonField<String> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimum: JsonField<Minimum> = JsonMissing.of()
-        private var minimumAmount: JsonField<String> = JsonMissing.of()
-        private var paidAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var paymentAttempts: JsonField<List<PaymentAttempt>> = JsonMissing.of()
-        private var paymentFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var paymentStartedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var scheduledIssueAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var shippingAddress: JsonField<ShippingAddress> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var subscription: JsonField<Subscription> = JsonMissing.of()
-        private var subtotal: JsonField<String> = JsonMissing.of()
-        private var syncFailedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var targetDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var total: JsonField<String> = JsonMissing.of()
-        private var voidedAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var willAutoIssue: JsonField<Boolean> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amountDue: JsonField<String>? = null
+        private var autoCollection: JsonField<AutoCollection>? = null
+        private var billingAddress: JsonField<BillingAddress>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var creditNotes: JsonField<MutableList<CreditNote>>? = null
+        private var currency: JsonField<String>? = null
+        private var customer: JsonField<Customer>? = null
+        private var customerBalanceTransactions:
+            JsonField<MutableList<CustomerBalanceTransaction>>? =
+            null
+        private var customerTaxId: JsonField<CustomerTaxId>? = null
+        private var discount: JsonValue? = null
+        private var discounts: JsonField<MutableList<InvoiceLevelDiscount>>? = null
+        private var dueDate: JsonField<OffsetDateTime>? = null
+        private var eligibleToIssueAt: JsonField<OffsetDateTime>? = null
+        private var hostedInvoiceUrl: JsonField<String>? = null
+        private var invoiceNumber: JsonField<String>? = null
+        private var invoicePdf: JsonField<String>? = null
+        private var invoiceSource: JsonField<InvoiceSource>? = null
+        private var issueFailedAt: JsonField<OffsetDateTime>? = null
+        private var issuedAt: JsonField<OffsetDateTime>? = null
+        private var lineItems: JsonField<MutableList<LineItem>>? = null
+        private var maximum: JsonField<Maximum>? = null
+        private var maximumAmount: JsonField<String>? = null
+        private var memo: JsonField<String>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimum: JsonField<Minimum>? = null
+        private var minimumAmount: JsonField<String>? = null
+        private var paidAt: JsonField<OffsetDateTime>? = null
+        private var paymentAttempts: JsonField<MutableList<PaymentAttempt>>? = null
+        private var paymentFailedAt: JsonField<OffsetDateTime>? = null
+        private var paymentStartedAt: JsonField<OffsetDateTime>? = null
+        private var scheduledIssueAt: JsonField<OffsetDateTime>? = null
+        private var shippingAddress: JsonField<ShippingAddress>? = null
+        private var status: JsonField<Status>? = null
+        private var subscription: JsonField<Subscription>? = null
+        private var subtotal: JsonField<String>? = null
+        private var syncFailedAt: JsonField<OffsetDateTime>? = null
+        private var targetDate: JsonField<OffsetDateTime>? = null
+        private var total: JsonField<String>? = null
+        private var voidedAt: JsonField<OffsetDateTime>? = null
+        private var willAutoIssue: JsonField<Boolean>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -793,13 +839,14 @@ private constructor(
             autoCollection = invoiceFetchUpcomingResponse.autoCollection
             billingAddress = invoiceFetchUpcomingResponse.billingAddress
             createdAt = invoiceFetchUpcomingResponse.createdAt
-            creditNotes = invoiceFetchUpcomingResponse.creditNotes
+            creditNotes = invoiceFetchUpcomingResponse.creditNotes.map { it.toMutableList() }
             currency = invoiceFetchUpcomingResponse.currency
             customer = invoiceFetchUpcomingResponse.customer
-            customerBalanceTransactions = invoiceFetchUpcomingResponse.customerBalanceTransactions
+            customerBalanceTransactions =
+                invoiceFetchUpcomingResponse.customerBalanceTransactions.map { it.toMutableList() }
             customerTaxId = invoiceFetchUpcomingResponse.customerTaxId
             discount = invoiceFetchUpcomingResponse.discount
-            discounts = invoiceFetchUpcomingResponse.discounts
+            discounts = invoiceFetchUpcomingResponse.discounts.map { it.toMutableList() }
             dueDate = invoiceFetchUpcomingResponse.dueDate
             eligibleToIssueAt = invoiceFetchUpcomingResponse.eligibleToIssueAt
             hostedInvoiceUrl = invoiceFetchUpcomingResponse.hostedInvoiceUrl
@@ -808,7 +855,7 @@ private constructor(
             invoiceSource = invoiceFetchUpcomingResponse.invoiceSource
             issueFailedAt = invoiceFetchUpcomingResponse.issueFailedAt
             issuedAt = invoiceFetchUpcomingResponse.issuedAt
-            lineItems = invoiceFetchUpcomingResponse.lineItems
+            lineItems = invoiceFetchUpcomingResponse.lineItems.map { it.toMutableList() }
             maximum = invoiceFetchUpcomingResponse.maximum
             maximumAmount = invoiceFetchUpcomingResponse.maximumAmount
             memo = invoiceFetchUpcomingResponse.memo
@@ -816,7 +863,8 @@ private constructor(
             minimum = invoiceFetchUpcomingResponse.minimum
             minimumAmount = invoiceFetchUpcomingResponse.minimumAmount
             paidAt = invoiceFetchUpcomingResponse.paidAt
-            paymentAttempts = invoiceFetchUpcomingResponse.paymentAttempts
+            paymentAttempts =
+                invoiceFetchUpcomingResponse.paymentAttempts.map { it.toMutableList() }
             paymentFailedAt = invoiceFetchUpcomingResponse.paymentFailedAt
             paymentStartedAt = invoiceFetchUpcomingResponse.paymentStartedAt
             scheduledIssueAt = invoiceFetchUpcomingResponse.scheduledIssueAt
@@ -855,8 +903,11 @@ private constructor(
             this.autoCollection = autoCollection
         }
 
-        fun billingAddress(billingAddress: BillingAddress) =
-            billingAddress(JsonField.of(billingAddress))
+        fun billingAddress(billingAddress: BillingAddress?) =
+            billingAddress(JsonField.ofNullable(billingAddress))
+
+        fun billingAddress(billingAddress: Optional<BillingAddress>) =
+            billingAddress(billingAddress.orElse(null))
 
         fun billingAddress(billingAddress: JsonField<BillingAddress>) = apply {
             this.billingAddress = billingAddress
@@ -873,7 +924,21 @@ private constructor(
 
         /** A list of credit notes associated with the invoice */
         fun creditNotes(creditNotes: JsonField<List<CreditNote>>) = apply {
-            this.creditNotes = creditNotes
+            this.creditNotes = creditNotes.map { it.toMutableList() }
+        }
+
+        /** A list of credit notes associated with the invoice */
+        fun addCreditNote(creditNote: CreditNote) = apply {
+            creditNotes =
+                (creditNotes ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(creditNote)
+                }
         }
 
         /** An ISO 4217 currency string or `credits` */
@@ -892,7 +957,24 @@ private constructor(
 
         fun customerBalanceTransactions(
             customerBalanceTransactions: JsonField<List<CustomerBalanceTransaction>>
-        ) = apply { this.customerBalanceTransactions = customerBalanceTransactions }
+        ) = apply {
+            this.customerBalanceTransactions =
+                customerBalanceTransactions.map { it.toMutableList() }
+        }
+
+        fun addCustomerBalanceTransaction(customerBalanceTransaction: CustomerBalanceTransaction) =
+            apply {
+                customerBalanceTransactions =
+                    (customerBalanceTransactions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(customerBalanceTransaction)
+                    }
+            }
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1000,7 +1082,117 @@ private constructor(
          * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
          * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
          */
-        fun customerTaxId(customerTaxId: CustomerTaxId) = customerTaxId(JsonField.of(customerTaxId))
+        fun customerTaxId(customerTaxId: CustomerTaxId?) =
+            customerTaxId(JsonField.ofNullable(customerTaxId))
+
+        /**
+         * Tax IDs are commonly required to be displayed on customer invoices, which are added to
+         * the headers of invoices.
+         *
+         * ### Supported Tax ID Countries and Types
+         * |Country             |Type        |Description                                                                                            |
+         * |--------------------|------------|-------------------------------------------------------------------------------------------------------|
+         * |Andorra             |`ad_nrt`    |Andorran NRT Number                                                                                    |
+         * |Argentina           |`ar_cuit`   |Argentinian Tax ID Number                                                                              |
+         * |Australia           |`au_abn`    |Australian Business Number (AU ABN)                                                                    |
+         * |Australia           |`au_arn`    |Australian Taxation Office Reference Number                                                            |
+         * |Austria             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bahrain             |`bh_vat`    |Bahraini VAT Number                                                                                    |
+         * |Belgium             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Bolivia             |`bo_tin`    |Bolivian Tax ID                                                                                        |
+         * |Brazil              |`br_cnpj`   |Brazilian CNPJ Number                                                                                  |
+         * |Brazil              |`br_cpf`    |Brazilian CPF Number                                                                                   |
+         * |Bulgaria            |`bg_uic`    |Bulgaria Unified Identification Code                                                                   |
+         * |Bulgaria            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Canada              |`ca_bn`     |Canadian BN                                                                                            |
+         * |Canada              |`ca_gst_hst`|Canadian GST/HST Number                                                                                |
+         * |Canada              |`ca_pst_bc` |Canadian PST Number (British Columbia)                                                                 |
+         * |Canada              |`ca_pst_mb` |Canadian PST Number (Manitoba)                                                                         |
+         * |Canada              |`ca_pst_sk` |Canadian PST Number (Saskatchewan)                                                                     |
+         * |Canada              |`ca_qst`    |Canadian QST Number (Québec)                                                                           |
+         * |Chile               |`cl_tin`    |Chilean TIN                                                                                            |
+         * |China               |`cn_tin`    |Chinese Tax ID                                                                                         |
+         * |Colombia            |`co_nit`    |Colombian NIT Number                                                                                   |
+         * |Costa Rica          |`cr_tin`    |Costa Rican Tax ID                                                                                     |
+         * |Croatia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Cyprus              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Czech Republic      |`eu_vat`    |European VAT Number                                                                                    |
+         * |Denmark             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Dominican Republic  |`do_rcn`    |Dominican RCN Number                                                                                   |
+         * |Ecuador             |`ec_ruc`    |Ecuadorian RUC Number                                                                                  |
+         * |Egypt               |`eg_tin`    |Egyptian Tax Identification Number                                                                     |
+         * |El Salvador         |`sv_nit`    |El Salvadorian NIT Number                                                                              |
+         * |Estonia             |`eu_vat`    |European VAT Number                                                                                    |
+         * |EU                  |`eu_oss_vat`|European One Stop Shop VAT Number for non-Union scheme                                                 |
+         * |Finland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |France              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Georgia             |`ge_vat`    |Georgian VAT                                                                                           |
+         * |Germany             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Greece              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hong Kong           |`hk_br`     |Hong Kong BR Number                                                                                    |
+         * |Hungary             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Hungary             |`hu_tin`    |Hungary Tax Number (adószám)                                                                           |
+         * |Iceland             |`is_vat`    |Icelandic VAT                                                                                          |
+         * |India               |`in_gst`    |Indian GST Number                                                                                      |
+         * |Indonesia           |`id_npwp`   |Indonesian NPWP Number                                                                                 |
+         * |Ireland             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Israel              |`il_vat`    |Israel VAT                                                                                             |
+         * |Italy               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Japan               |`jp_cn`     |Japanese Corporate Number (_Hōjin Bangō_)                                                              |
+         * |Japan               |`jp_rn`     |Japanese Registered Foreign Businesses' Registration Number (_Tōroku Kokugai Jigyōsha no Tōroku Bangō_)|
+         * |Japan               |`jp_trn`    |Japanese Tax Registration Number (_Tōroku Bangō_)                                                      |
+         * |Kazakhstan          |`kz_bin`    |Kazakhstani Business Identification Number                                                             |
+         * |Kenya               |`ke_pin`    |Kenya Revenue Authority Personal Identification Number                                                 |
+         * |Latvia              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Liechtenstein       |`li_uid`    |Liechtensteinian UID Number                                                                            |
+         * |Lithuania           |`eu_vat`    |European VAT Number                                                                                    |
+         * |Luxembourg          |`eu_vat`    |European VAT Number                                                                                    |
+         * |Malaysia            |`my_frp`    |Malaysian FRP Number                                                                                   |
+         * |Malaysia            |`my_itn`    |Malaysian ITN                                                                                          |
+         * |Malaysia            |`my_sst`    |Malaysian SST Number                                                                                   |
+         * |Malta               |`eu_vat `   |European VAT Number                                                                                    |
+         * |Mexico              |`mx_rfc`    |Mexican RFC Number                                                                                     |
+         * |Netherlands         |`eu_vat`    |European VAT Number                                                                                    |
+         * |New Zealand         |`nz_gst`    |New Zealand GST Number                                                                                 |
+         * |Nigeria             |`ng_tin`    |Nigerian Tax Identification Number                                                                     |
+         * |Norway              |`no_vat`    |Norwegian VAT Number                                                                                   |
+         * |Norway              |`no_voec`   |Norwegian VAT on e-commerce Number                                                                     |
+         * |Oman                |`om_vat`    |Omani VAT Number                                                                                       |
+         * |Peru                |`pe_ruc`    |Peruvian RUC Number                                                                                    |
+         * |Philippines         |`ph_tin `   |Philippines Tax Identification Number                                                                  |
+         * |Poland              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Portugal            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`eu_vat`    |European VAT Number                                                                                    |
+         * |Romania             |`ro_tin`    |Romanian Tax ID Number                                                                                 |
+         * |Russia              |`ru_inn`    |Russian INN                                                                                            |
+         * |Russia              |`ru_kpp`    |Russian KPP                                                                                            |
+         * |Saudi Arabia        |`sa_vat`    |Saudi Arabia VAT                                                                                       |
+         * |Serbia              |`rs_pib`    |Serbian PIB Number                                                                                     |
+         * |Singapore           |`sg_gst`    |Singaporean GST                                                                                        |
+         * |Singapore           |`sg_uen`    |Singaporean UEN                                                                                        |
+         * |Slovakia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`eu_vat`    |European VAT Number                                                                                    |
+         * |Slovenia            |`si_tin`    |Slovenia Tax Number (davčna številka)                                                                  |
+         * |South Africa        |`za_vat`    |South African VAT Number                                                                               |
+         * |South Korea         |`kr_brn`    |Korean BRN                                                                                             |
+         * |Spain               |`es_cif`    |Spanish NIF Number (previously Spanish CIF Number)                                                     |
+         * |Spain               |`eu_vat`    |European VAT Number                                                                                    |
+         * |Sweden              |`eu_vat`    |European VAT Number                                                                                    |
+         * |Switzerland         |`ch_vat`    |Switzerland VAT Number                                                                                 |
+         * |Taiwan              |`tw_vat`    |Taiwanese VAT                                                                                          |
+         * |Thailand            |`th_vat`    |Thai VAT                                                                                               |
+         * |Turkey              |`tr_tin`    |Turkish Tax Identification Number                                                                      |
+         * |Ukraine             |`ua_vat`    |Ukrainian VAT                                                                                          |
+         * |United Arab Emirates|`ae_trn`    |United Arab Emirates TRN                                                                               |
+         * |United Kingdom      |`eu_vat`    |Northern Ireland VAT Number                                                                            |
+         * |United Kingdom      |`gb_vat`    |United Kingdom VAT Number                                                                              |
+         * |United States       |`us_ein`    |United States EIN                                                                                      |
+         * |Uruguay             |`uy_ruc`    |Uruguayan RUC Number                                                                                   |
+         * |Venezuela           |`ve_rif`    |Venezuelan RIF Number                                                                                  |
+         * |Vietnam             |`vn_tin`    |Vietnamese Tax ID Number                                                                               |
+         */
+        fun customerTaxId(customerTaxId: Optional<CustomerTaxId>) =
+            customerTaxId(customerTaxId.orElse(null))
 
         /**
          * Tax IDs are commonly required to be displayed on customer invoices, which are added to
@@ -1122,7 +1314,20 @@ private constructor(
         fun discounts(discounts: List<InvoiceLevelDiscount>) = discounts(JsonField.of(discounts))
 
         fun discounts(discounts: JsonField<List<InvoiceLevelDiscount>>) = apply {
-            this.discounts = discounts
+            this.discounts = discounts.map { it.toMutableList() }
+        }
+
+        fun addDiscount(discount: InvoiceLevelDiscount) = apply {
+            discounts =
+                (discounts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discount)
+                }
         }
 
         /** When the invoice payment is due. */
@@ -1136,8 +1341,16 @@ private constructor(
          * eligible to be issued, otherwise it will be `null`. If `auto-issue` is true, the invoice
          * will automatically begin issuing at this time.
          */
-        fun eligibleToIssueAt(eligibleToIssueAt: OffsetDateTime) =
-            eligibleToIssueAt(JsonField.of(eligibleToIssueAt))
+        fun eligibleToIssueAt(eligibleToIssueAt: OffsetDateTime?) =
+            eligibleToIssueAt(JsonField.ofNullable(eligibleToIssueAt))
+
+        /**
+         * If the invoice has a status of `draft`, this will be the time that the invoice will be
+         * eligible to be issued, otherwise it will be `null`. If `auto-issue` is true, the invoice
+         * will automatically begin issuing at this time.
+         */
+        fun eligibleToIssueAt(eligibleToIssueAt: Optional<OffsetDateTime>) =
+            eligibleToIssueAt(eligibleToIssueAt.orElse(null))
 
         /**
          * If the invoice has a status of `draft`, this will be the time that the invoice will be
@@ -1152,8 +1365,15 @@ private constructor(
          * A URL for the customer-facing invoice portal. This URL expires 30 days after the
          * invoice's due date, or 60 days after being re-generated through the UI.
          */
-        fun hostedInvoiceUrl(hostedInvoiceUrl: String) =
-            hostedInvoiceUrl(JsonField.of(hostedInvoiceUrl))
+        fun hostedInvoiceUrl(hostedInvoiceUrl: String?) =
+            hostedInvoiceUrl(JsonField.ofNullable(hostedInvoiceUrl))
+
+        /**
+         * A URL for the customer-facing invoice portal. This URL expires 30 days after the
+         * invoice's due date, or 60 days after being re-generated through the UI.
+         */
+        fun hostedInvoiceUrl(hostedInvoiceUrl: Optional<String>) =
+            hostedInvoiceUrl(hostedInvoiceUrl.orElse(null))
 
         /**
          * A URL for the customer-facing invoice portal. This URL expires 30 days after the
@@ -1178,7 +1398,10 @@ private constructor(
         }
 
         /** The link to download the PDF representation of the `Invoice`. */
-        fun invoicePdf(invoicePdf: String) = invoicePdf(JsonField.of(invoicePdf))
+        fun invoicePdf(invoicePdf: String?) = invoicePdf(JsonField.ofNullable(invoicePdf))
+
+        /** The link to download the PDF representation of the `Invoice`. */
+        fun invoicePdf(invoicePdf: Optional<String>) = invoicePdf(invoicePdf.orElse(null))
 
         /** The link to download the PDF representation of the `Invoice`. */
         fun invoicePdf(invoicePdf: JsonField<String>) = apply { this.invoicePdf = invoicePdf }
@@ -1193,8 +1416,15 @@ private constructor(
          * If the invoice failed to issue, this will be the last time it failed to issue (even if it
          * is now in a different state.)
          */
-        fun issueFailedAt(issueFailedAt: OffsetDateTime) =
-            issueFailedAt(JsonField.of(issueFailedAt))
+        fun issueFailedAt(issueFailedAt: OffsetDateTime?) =
+            issueFailedAt(JsonField.ofNullable(issueFailedAt))
+
+        /**
+         * If the invoice failed to issue, this will be the last time it failed to issue (even if it
+         * is now in a different state.)
+         */
+        fun issueFailedAt(issueFailedAt: Optional<OffsetDateTime>) =
+            issueFailedAt(issueFailedAt.orElse(null))
 
         /**
          * If the invoice failed to issue, this will be the last time it failed to issue (even if it
@@ -1208,7 +1438,13 @@ private constructor(
          * If the invoice has been issued, this will be the time it transitioned to `issued` (even
          * if it is now in a different state.)
          */
-        fun issuedAt(issuedAt: OffsetDateTime) = issuedAt(JsonField.of(issuedAt))
+        fun issuedAt(issuedAt: OffsetDateTime?) = issuedAt(JsonField.ofNullable(issuedAt))
+
+        /**
+         * If the invoice has been issued, this will be the time it transitioned to `issued` (even
+         * if it is now in a different state.)
+         */
+        fun issuedAt(issuedAt: Optional<OffsetDateTime>) = issuedAt(issuedAt.orElse(null))
 
         /**
          * If the invoice has been issued, this will be the time it transitioned to `issued` (even
@@ -1220,20 +1456,45 @@ private constructor(
         fun lineItems(lineItems: List<LineItem>) = lineItems(JsonField.of(lineItems))
 
         /** The breakdown of prices in this invoice. */
-        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply { this.lineItems = lineItems }
+        fun lineItems(lineItems: JsonField<List<LineItem>>) = apply {
+            this.lineItems = lineItems.map { it.toMutableList() }
+        }
 
-        fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+        /** The breakdown of prices in this invoice. */
+        fun addLineItem(lineItem: LineItem) = apply {
+            lineItems =
+                (lineItems ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(lineItem)
+                }
+        }
+
+        fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+        fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
         fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-        fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+        fun maximumAmount(maximumAmount: String?) =
+            maximumAmount(JsonField.ofNullable(maximumAmount))
+
+        fun maximumAmount(maximumAmount: Optional<String>) =
+            maximumAmount(maximumAmount.orElse(null))
 
         fun maximumAmount(maximumAmount: JsonField<String>) = apply {
             this.maximumAmount = maximumAmount
         }
 
         /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
-        fun memo(memo: String) = memo(JsonField.of(memo))
+        fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+        /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+        fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
         /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
         fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -1252,11 +1513,17 @@ private constructor(
          */
         fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-        fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+        fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+        fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
         fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-        fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+        fun minimumAmount(minimumAmount: String?) =
+            minimumAmount(JsonField.ofNullable(minimumAmount))
+
+        fun minimumAmount(minimumAmount: Optional<String>) =
+            minimumAmount(minimumAmount.orElse(null))
 
         fun minimumAmount(minimumAmount: JsonField<String>) = apply {
             this.minimumAmount = minimumAmount
@@ -1265,7 +1532,12 @@ private constructor(
         /**
          * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
          */
-        fun paidAt(paidAt: OffsetDateTime) = paidAt(JsonField.of(paidAt))
+        fun paidAt(paidAt: OffsetDateTime?) = paidAt(JsonField.ofNullable(paidAt))
+
+        /**
+         * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
+         */
+        fun paidAt(paidAt: Optional<OffsetDateTime>) = paidAt(paidAt.orElse(null))
 
         /**
          * If the invoice has a status of `paid`, this gives a timestamp when the invoice was paid.
@@ -1278,15 +1550,36 @@ private constructor(
 
         /** A list of payment attempts associated with the invoice */
         fun paymentAttempts(paymentAttempts: JsonField<List<PaymentAttempt>>) = apply {
-            this.paymentAttempts = paymentAttempts
+            this.paymentAttempts = paymentAttempts.map { it.toMutableList() }
+        }
+
+        /** A list of payment attempts associated with the invoice */
+        fun addPaymentAttempt(paymentAttempt: PaymentAttempt) = apply {
+            paymentAttempts =
+                (paymentAttempts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(paymentAttempt)
+                }
         }
 
         /**
          * If payment was attempted on this invoice but failed, this will be the time of the most
          * recent attempt.
          */
-        fun paymentFailedAt(paymentFailedAt: OffsetDateTime) =
-            paymentFailedAt(JsonField.of(paymentFailedAt))
+        fun paymentFailedAt(paymentFailedAt: OffsetDateTime?) =
+            paymentFailedAt(JsonField.ofNullable(paymentFailedAt))
+
+        /**
+         * If payment was attempted on this invoice but failed, this will be the time of the most
+         * recent attempt.
+         */
+        fun paymentFailedAt(paymentFailedAt: Optional<OffsetDateTime>) =
+            paymentFailedAt(paymentFailedAt.orElse(null))
 
         /**
          * If payment was attempted on this invoice but failed, this will be the time of the most
@@ -1301,8 +1594,16 @@ private constructor(
          * attempt. This field is especially useful for delayed-notification payment mechanisms
          * (like bank transfers), where payment can take 3 days or more.
          */
-        fun paymentStartedAt(paymentStartedAt: OffsetDateTime) =
-            paymentStartedAt(JsonField.of(paymentStartedAt))
+        fun paymentStartedAt(paymentStartedAt: OffsetDateTime?) =
+            paymentStartedAt(JsonField.ofNullable(paymentStartedAt))
+
+        /**
+         * If payment was attempted on this invoice, this will be the start time of the most recent
+         * attempt. This field is especially useful for delayed-notification payment mechanisms
+         * (like bank transfers), where payment can take 3 days or more.
+         */
+        fun paymentStartedAt(paymentStartedAt: Optional<OffsetDateTime>) =
+            paymentStartedAt(paymentStartedAt.orElse(null))
 
         /**
          * If payment was attempted on this invoice, this will be the start time of the most recent
@@ -1317,8 +1618,15 @@ private constructor(
          * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
          * be issued.
          */
-        fun scheduledIssueAt(scheduledIssueAt: OffsetDateTime) =
-            scheduledIssueAt(JsonField.of(scheduledIssueAt))
+        fun scheduledIssueAt(scheduledIssueAt: OffsetDateTime?) =
+            scheduledIssueAt(JsonField.ofNullable(scheduledIssueAt))
+
+        /**
+         * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
+         * be issued.
+         */
+        fun scheduledIssueAt(scheduledIssueAt: Optional<OffsetDateTime>) =
+            scheduledIssueAt(scheduledIssueAt.orElse(null))
 
         /**
          * If the invoice is in draft, this timestamp will reflect when the invoice is scheduled to
@@ -1328,8 +1636,11 @@ private constructor(
             this.scheduledIssueAt = scheduledIssueAt
         }
 
-        fun shippingAddress(shippingAddress: ShippingAddress) =
-            shippingAddress(JsonField.of(shippingAddress))
+        fun shippingAddress(shippingAddress: ShippingAddress?) =
+            shippingAddress(JsonField.ofNullable(shippingAddress))
+
+        fun shippingAddress(shippingAddress: Optional<ShippingAddress>) =
+            shippingAddress(shippingAddress.orElse(null))
 
         fun shippingAddress(shippingAddress: JsonField<ShippingAddress>) = apply {
             this.shippingAddress = shippingAddress
@@ -1339,7 +1650,11 @@ private constructor(
 
         fun status(status: JsonField<Status>) = apply { this.status = status }
 
-        fun subscription(subscription: Subscription) = subscription(JsonField.of(subscription))
+        fun subscription(subscription: Subscription?) =
+            subscription(JsonField.ofNullable(subscription))
+
+        fun subscription(subscription: Optional<Subscription>) =
+            subscription(subscription.orElse(null))
 
         fun subscription(subscription: JsonField<Subscription>) = apply {
             this.subscription = subscription
@@ -1355,7 +1670,15 @@ private constructor(
          * If the invoice failed to sync, this will be the last time an external invoicing provider
          * sync was attempted. This field will always be `null` for invoices using Orb Invoicing.
          */
-        fun syncFailedAt(syncFailedAt: OffsetDateTime) = syncFailedAt(JsonField.of(syncFailedAt))
+        fun syncFailedAt(syncFailedAt: OffsetDateTime?) =
+            syncFailedAt(JsonField.ofNullable(syncFailedAt))
+
+        /**
+         * If the invoice failed to sync, this will be the last time an external invoicing provider
+         * sync was attempted. This field will always be `null` for invoices using Orb Invoicing.
+         */
+        fun syncFailedAt(syncFailedAt: Optional<OffsetDateTime>) =
+            syncFailedAt(syncFailedAt.orElse(null))
 
         /**
          * If the invoice failed to sync, this will be the last time an external invoicing provider
@@ -1383,7 +1706,13 @@ private constructor(
          * If the invoice has a status of `void`, this gives a timestamp when the invoice was
          * voided.
          */
-        fun voidedAt(voidedAt: OffsetDateTime) = voidedAt(JsonField.of(voidedAt))
+        fun voidedAt(voidedAt: OffsetDateTime?) = voidedAt(JsonField.ofNullable(voidedAt))
+
+        /**
+         * If the invoice has a status of `void`, this gives a timestamp when the invoice was
+         * voided.
+         */
+        fun voidedAt(voidedAt: Optional<OffsetDateTime>) = voidedAt(voidedAt.orElse(null))
 
         /**
          * If the invoice has a status of `void`, this gives a timestamp when the invoice was
@@ -1426,47 +1755,56 @@ private constructor(
 
         fun build(): InvoiceFetchUpcomingResponse =
             InvoiceFetchUpcomingResponse(
-                id,
-                amountDue,
-                autoCollection,
-                billingAddress,
-                createdAt,
-                creditNotes.map { it.toImmutable() },
-                currency,
-                customer,
-                customerBalanceTransactions.map { it.toImmutable() },
-                customerTaxId,
-                discount,
-                discounts.map { it.toImmutable() },
-                dueDate,
-                eligibleToIssueAt,
-                hostedInvoiceUrl,
-                invoiceNumber,
-                invoicePdf,
-                invoiceSource,
-                issueFailedAt,
-                issuedAt,
-                lineItems.map { it.toImmutable() },
-                maximum,
-                maximumAmount,
-                memo,
-                metadata,
-                minimum,
-                minimumAmount,
-                paidAt,
-                paymentAttempts.map { it.toImmutable() },
-                paymentFailedAt,
-                paymentStartedAt,
-                scheduledIssueAt,
-                shippingAddress,
-                status,
-                subscription,
-                subtotal,
-                syncFailedAt,
-                targetDate,
-                total,
-                voidedAt,
-                willAutoIssue,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amountDue) { "`amountDue` is required but was not set" },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingAddress) { "`billingAddress` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(creditNotes) { "`creditNotes` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(customerBalanceTransactions) {
+                        "`customerBalanceTransactions` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(customerTaxId) { "`customerTaxId` is required but was not set" },
+                checkNotNull(discount) { "`discount` is required but was not set" },
+                checkNotNull(discounts) { "`discounts` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(dueDate) { "`dueDate` is required but was not set" },
+                checkNotNull(eligibleToIssueAt) {
+                    "`eligibleToIssueAt` is required but was not set"
+                },
+                checkNotNull(hostedInvoiceUrl) { "`hostedInvoiceUrl` is required but was not set" },
+                checkNotNull(invoiceNumber) { "`invoiceNumber` is required but was not set" },
+                checkNotNull(invoicePdf) { "`invoicePdf` is required but was not set" },
+                checkNotNull(invoiceSource) { "`invoiceSource` is required but was not set" },
+                checkNotNull(issueFailedAt) { "`issueFailedAt` is required but was not set" },
+                checkNotNull(issuedAt) { "`issuedAt` is required but was not set" },
+                checkNotNull(lineItems) { "`lineItems` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(maximum) { "`maximum` is required but was not set" },
+                checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                checkNotNull(memo) { "`memo` is required but was not set" },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimum) { "`minimum` is required but was not set" },
+                checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                checkNotNull(paidAt) { "`paidAt` is required but was not set" },
+                checkNotNull(paymentAttempts) { "`paymentAttempts` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(paymentFailedAt) { "`paymentFailedAt` is required but was not set" },
+                checkNotNull(paymentStartedAt) { "`paymentStartedAt` is required but was not set" },
+                checkNotNull(scheduledIssueAt) { "`scheduledIssueAt` is required but was not set" },
+                checkNotNull(shippingAddress) { "`shippingAddress` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(subscription) { "`subscription` is required but was not set" },
+                checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                checkNotNull(syncFailedAt) { "`syncFailedAt` is required but was not set" },
+                checkNotNull(targetDate) { "`targetDate` is required but was not set" },
+                checkNotNull(total) { "`total` is required but was not set" },
+                checkNotNull(voidedAt) { "`voidedAt` is required but was not set" },
+                checkNotNull(willAutoIssue) { "`willAutoIssue` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -1518,17 +1856,21 @@ private constructor(
             Optional.ofNullable(previouslyAttemptedAt.getNullable("previously_attempted_at"))
 
         /** True only if auto-collection is enabled for this invoice. */
-        @JsonProperty("enabled") @ExcludeMissing fun _enabled() = enabled
+        @JsonProperty("enabled") @ExcludeMissing fun _enabled(): JsonField<Boolean> = enabled
 
         /**
          * If the invoice is scheduled for auto-collection, this field will reflect when the next
          * attempt will occur. If dunning has been exhausted, or auto-collection is not enabled for
          * this invoice, this field will be `null`.
          */
-        @JsonProperty("next_attempt_at") @ExcludeMissing fun _nextAttemptAt() = nextAttemptAt
+        @JsonProperty("next_attempt_at")
+        @ExcludeMissing
+        fun _nextAttemptAt(): JsonField<OffsetDateTime> = nextAttemptAt
 
         /** Number of auto-collection payment attempts. */
-        @JsonProperty("num_attempts") @ExcludeMissing fun _numAttempts() = numAttempts
+        @JsonProperty("num_attempts")
+        @ExcludeMissing
+        fun _numAttempts(): JsonField<Long> = numAttempts
 
         /**
          * If Orb has ever attempted payment auto-collection for this invoice, this field will
@@ -1540,7 +1882,7 @@ private constructor(
          */
         @JsonProperty("previously_attempted_at")
         @ExcludeMissing
-        fun _previouslyAttemptedAt() = previouslyAttemptedAt
+        fun _previouslyAttemptedAt(): JsonField<OffsetDateTime> = previouslyAttemptedAt
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1567,10 +1909,10 @@ private constructor(
 
         class Builder {
 
-            private var enabled: JsonField<Boolean> = JsonMissing.of()
-            private var nextAttemptAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var numAttempts: JsonField<Long> = JsonMissing.of()
-            private var previouslyAttemptedAt: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var enabled: JsonField<Boolean>? = null
+            private var nextAttemptAt: JsonField<OffsetDateTime>? = null
+            private var numAttempts: JsonField<Long>? = null
+            private var previouslyAttemptedAt: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1583,7 +1925,14 @@ private constructor(
             }
 
             /** True only if auto-collection is enabled for this invoice. */
-            fun enabled(enabled: Boolean) = enabled(JsonField.of(enabled))
+            fun enabled(enabled: Boolean?) = enabled(JsonField.ofNullable(enabled))
+
+            /** True only if auto-collection is enabled for this invoice. */
+            fun enabled(enabled: Boolean) = enabled(enabled as Boolean?)
+
+            /** True only if auto-collection is enabled for this invoice. */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun enabled(enabled: Optional<Boolean>) = enabled(enabled.orElse(null) as Boolean?)
 
             /** True only if auto-collection is enabled for this invoice. */
             fun enabled(enabled: JsonField<Boolean>) = apply { this.enabled = enabled }
@@ -1593,8 +1942,16 @@ private constructor(
              * next attempt will occur. If dunning has been exhausted, or auto-collection is not
              * enabled for this invoice, this field will be `null`.
              */
-            fun nextAttemptAt(nextAttemptAt: OffsetDateTime) =
-                nextAttemptAt(JsonField.of(nextAttemptAt))
+            fun nextAttemptAt(nextAttemptAt: OffsetDateTime?) =
+                nextAttemptAt(JsonField.ofNullable(nextAttemptAt))
+
+            /**
+             * If the invoice is scheduled for auto-collection, this field will reflect when the
+             * next attempt will occur. If dunning has been exhausted, or auto-collection is not
+             * enabled for this invoice, this field will be `null`.
+             */
+            fun nextAttemptAt(nextAttemptAt: Optional<OffsetDateTime>) =
+                nextAttemptAt(nextAttemptAt.orElse(null))
 
             /**
              * If the invoice is scheduled for auto-collection, this field will reflect when the
@@ -1606,7 +1963,15 @@ private constructor(
             }
 
             /** Number of auto-collection payment attempts. */
-            fun numAttempts(numAttempts: Long) = numAttempts(JsonField.of(numAttempts))
+            fun numAttempts(numAttempts: Long?) = numAttempts(JsonField.ofNullable(numAttempts))
+
+            /** Number of auto-collection payment attempts. */
+            fun numAttempts(numAttempts: Long) = numAttempts(numAttempts as Long?)
+
+            /** Number of auto-collection payment attempts. */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun numAttempts(numAttempts: Optional<Long>) =
+                numAttempts(numAttempts.orElse(null) as Long?)
 
             /** Number of auto-collection payment attempts. */
             fun numAttempts(numAttempts: JsonField<Long>) = apply { this.numAttempts = numAttempts }
@@ -1619,8 +1984,19 @@ private constructor(
              * dunning has been exhausted (`previously_attempted_at` is non-null, but
              * `next_attempt_time` is null).
              */
-            fun previouslyAttemptedAt(previouslyAttemptedAt: OffsetDateTime) =
-                previouslyAttemptedAt(JsonField.of(previouslyAttemptedAt))
+            fun previouslyAttemptedAt(previouslyAttemptedAt: OffsetDateTime?) =
+                previouslyAttemptedAt(JsonField.ofNullable(previouslyAttemptedAt))
+
+            /**
+             * If Orb has ever attempted payment auto-collection for this invoice, this field will
+             * reflect when that attempt occurred. In conjunction with `next_attempt_at`, this can
+             * be used to tell whether the invoice is currently in dunning (that is,
+             * `previously_attempted_at` is non-null, and `next_attempt_time` is non-null), or if
+             * dunning has been exhausted (`previously_attempted_at` is non-null, but
+             * `next_attempt_time` is null).
+             */
+            fun previouslyAttemptedAt(previouslyAttemptedAt: Optional<OffsetDateTime>) =
+                previouslyAttemptedAt(previouslyAttemptedAt.orElse(null))
 
             /**
              * If Orb has ever attempted payment auto-collection for this invoice, this field will
@@ -1655,10 +2031,12 @@ private constructor(
 
             fun build(): AutoCollection =
                 AutoCollection(
-                    enabled,
-                    nextAttemptAt,
-                    numAttempts,
-                    previouslyAttemptedAt,
+                    checkNotNull(enabled) { "`enabled` is required but was not set" },
+                    checkNotNull(nextAttemptAt) { "`nextAttemptAt` is required but was not set" },
+                    checkNotNull(numAttempts) { "`numAttempts` is required but was not set" },
+                    checkNotNull(previouslyAttemptedAt) {
+                        "`previouslyAttemptedAt` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1720,17 +2098,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1759,12 +2139,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1778,27 +2158,39 @@ private constructor(
                 additionalProperties = billingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -1823,12 +2215,12 @@ private constructor(
 
             fun build(): BillingAddress =
                 BillingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1898,26 +2290,28 @@ private constructor(
         fun voidedAt(): Optional<OffsetDateTime> =
             Optional.ofNullable(voidedAt.getNullable("voided_at"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("credit_note_number")
         @ExcludeMissing
-        fun _creditNoteNumber() = creditNoteNumber
+        fun _creditNoteNumber(): JsonField<String> = creditNoteNumber
 
         /** An optional memo supplied on the credit note. */
-        @JsonProperty("memo") @ExcludeMissing fun _memo() = memo
+        @JsonProperty("memo") @ExcludeMissing fun _memo(): JsonField<String> = memo
 
-        @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+        @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
-        @JsonProperty("total") @ExcludeMissing fun _total() = total
+        @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<String> = type
 
         /**
          * If the credit note has a status of `void`, this gives a timestamp when the credit note
          * was voided.
          */
-        @JsonProperty("voided_at") @ExcludeMissing fun _voidedAt() = voidedAt
+        @JsonProperty("voided_at")
+        @ExcludeMissing
+        fun _voidedAt(): JsonField<OffsetDateTime> = voidedAt
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1947,13 +2341,13 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var creditNoteNumber: JsonField<String> = JsonMissing.of()
-            private var memo: JsonField<String> = JsonMissing.of()
-            private var reason: JsonField<String> = JsonMissing.of()
-            private var total: JsonField<String> = JsonMissing.of()
-            private var type: JsonField<String> = JsonMissing.of()
-            private var voidedAt: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var creditNoteNumber: JsonField<String>? = null
+            private var memo: JsonField<String>? = null
+            private var reason: JsonField<String>? = null
+            private var total: JsonField<String>? = null
+            private var type: JsonField<String>? = null
+            private var voidedAt: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1980,7 +2374,10 @@ private constructor(
             }
 
             /** An optional memo supplied on the credit note. */
-            fun memo(memo: String) = memo(JsonField.of(memo))
+            fun memo(memo: String?) = memo(JsonField.ofNullable(memo))
+
+            /** An optional memo supplied on the credit note. */
+            fun memo(memo: Optional<String>) = memo(memo.orElse(null))
 
             /** An optional memo supplied on the credit note. */
             fun memo(memo: JsonField<String>) = apply { this.memo = memo }
@@ -2001,7 +2398,13 @@ private constructor(
              * If the credit note has a status of `void`, this gives a timestamp when the credit
              * note was voided.
              */
-            fun voidedAt(voidedAt: OffsetDateTime) = voidedAt(JsonField.of(voidedAt))
+            fun voidedAt(voidedAt: OffsetDateTime?) = voidedAt(JsonField.ofNullable(voidedAt))
+
+            /**
+             * If the credit note has a status of `void`, this gives a timestamp when the credit
+             * note was voided.
+             */
+            fun voidedAt(voidedAt: Optional<OffsetDateTime>) = voidedAt(voidedAt.orElse(null))
 
             /**
              * If the credit note has a status of `void`, this gives a timestamp when the credit
@@ -2030,13 +2433,15 @@ private constructor(
 
             fun build(): CreditNote =
                 CreditNote(
-                    id,
-                    creditNoteNumber,
-                    memo,
-                    reason,
-                    total,
-                    type,
-                    voidedAt,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(creditNoteNumber) {
+                        "`creditNoteNumber` is required but was not set"
+                    },
+                    checkNotNull(memo) { "`memo` is required but was not set" },
+                    checkNotNull(reason) { "`reason` is required but was not set" },
+                    checkNotNull(total) { "`total` is required but was not set" },
+                    checkNotNull(type) { "`type` is required but was not set" },
+                    checkNotNull(voidedAt) { "`voidedAt` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2076,11 +2481,11 @@ private constructor(
         fun externalCustomerId(): Optional<String> =
             Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonProperty("external_customer_id")
         @ExcludeMissing
-        fun _externalCustomerId() = externalCustomerId
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2105,8 +2510,8 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalCustomerId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2120,8 +2525,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun externalCustomerId(externalCustomerId: String) =
-                externalCustomerId(JsonField.of(externalCustomerId))
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
+
+            fun externalCustomerId(externalCustomerId: Optional<String>) =
+                externalCustomerId(externalCustomerId.orElse(null))
 
             fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
                 this.externalCustomerId = externalCustomerId
@@ -2148,8 +2556,10 @@ private constructor(
 
             fun build(): Customer =
                 Customer(
-                    id,
-                    externalCustomerId,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalCustomerId) {
+                        "`externalCustomerId` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2241,36 +2651,46 @@ private constructor(
         fun type(): Type = type.getRequired("type")
 
         /** A unique id for this transaction. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("action") @ExcludeMissing fun _action() = action
+        @JsonProperty("action") @ExcludeMissing fun _action(): JsonField<Action> = action
 
         /** The value of the amount changed in the transaction. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The creation time of this transaction. */
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("credit_note") @ExcludeMissing fun _creditNote() = creditNote
+        @JsonProperty("credit_note")
+        @ExcludeMissing
+        fun _creditNote(): JsonField<CreditNote> = creditNote
 
         /** An optional description provided for manual customer balance adjustments. */
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /**
          * The new value of the customer's balance prior to the transaction, in the customer's
          * currency.
          */
-        @JsonProperty("ending_balance") @ExcludeMissing fun _endingBalance() = endingBalance
+        @JsonProperty("ending_balance")
+        @ExcludeMissing
+        fun _endingBalance(): JsonField<String> = endingBalance
 
-        @JsonProperty("invoice") @ExcludeMissing fun _invoice() = invoice
+        @JsonProperty("invoice") @ExcludeMissing fun _invoice(): JsonField<Invoice> = invoice
 
         /**
          * The original value of the customer's balance prior to the transaction, in the customer's
          * currency.
          */
-        @JsonProperty("starting_balance") @ExcludeMissing fun _startingBalance() = startingBalance
+        @JsonProperty("starting_balance")
+        @ExcludeMissing
+        fun _startingBalance(): JsonField<String> = startingBalance
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2303,16 +2723,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var action: JsonField<Action> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditNote: JsonField<CreditNote> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var endingBalance: JsonField<String> = JsonMissing.of()
-            private var invoice: JsonField<Invoice> = JsonMissing.of()
-            private var startingBalance: JsonField<String> = JsonMissing.of()
-            private var type: JsonField<Type> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var action: JsonField<Action>? = null
+            private var amount: JsonField<String>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditNote: JsonField<CreditNote>? = null
+            private var description: JsonField<String>? = null
+            private var endingBalance: JsonField<String>? = null
+            private var invoice: JsonField<Invoice>? = null
+            private var startingBalance: JsonField<String>? = null
+            private var type: JsonField<Type>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2355,14 +2775,19 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditNote(creditNote: CreditNote) = creditNote(JsonField.of(creditNote))
+            fun creditNote(creditNote: CreditNote?) = creditNote(JsonField.ofNullable(creditNote))
+
+            fun creditNote(creditNote: Optional<CreditNote>) = creditNote(creditNote.orElse(null))
 
             fun creditNote(creditNote: JsonField<CreditNote>) = apply {
                 this.creditNote = creditNote
             }
 
             /** An optional description provided for manual customer balance adjustments. */
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            /** An optional description provided for manual customer balance adjustments. */
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             /** An optional description provided for manual customer balance adjustments. */
             fun description(description: JsonField<String>) = apply {
@@ -2383,7 +2808,9 @@ private constructor(
                 this.endingBalance = endingBalance
             }
 
-            fun invoice(invoice: Invoice) = invoice(JsonField.of(invoice))
+            fun invoice(invoice: Invoice?) = invoice(JsonField.ofNullable(invoice))
+
+            fun invoice(invoice: Optional<Invoice>) = invoice(invoice.orElse(null))
 
             fun invoice(invoice: JsonField<Invoice>) = apply { this.invoice = invoice }
 
@@ -2427,16 +2854,18 @@ private constructor(
 
             fun build(): CustomerBalanceTransaction =
                 CustomerBalanceTransaction(
-                    id,
-                    action,
-                    amount,
-                    createdAt,
-                    creditNote,
-                    description,
-                    endingBalance,
-                    invoice,
-                    startingBalance,
-                    type,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(action) { "`action` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditNote) { "`creditNote` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(endingBalance) { "`endingBalance` is required but was not set" },
+                    checkNotNull(invoice) { "`invoice` is required but was not set" },
+                    checkNotNull(startingBalance) {
+                        "`startingBalance` is required but was not set"
+                    },
+                    checkNotNull(type) { "`type` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2549,7 +2978,7 @@ private constructor(
             fun id(): String = id.getRequired("id")
 
             /** The id of the Credit note */
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2573,7 +3002,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2610,7 +3039,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): CreditNote = CreditNote(id, additionalProperties.toImmutable())
+                fun build(): CreditNote =
+                    CreditNote(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -2646,7 +3079,7 @@ private constructor(
             fun id(): String = id.getRequired("id")
 
             /** The Invoice id */
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2670,7 +3103,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2707,7 +3140,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): Invoice = Invoice(id, additionalProperties.toImmutable())
+                fun build(): Invoice =
+                    Invoice(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -2929,11 +3366,11 @@ private constructor(
 
         fun value(): String = value.getRequired("value")
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<Country> = country
 
-        @JsonProperty("type") @ExcludeMissing fun _type() = type
+        @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
-        @JsonProperty("value") @ExcludeMissing fun _value() = value
+        @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2959,9 +3396,9 @@ private constructor(
 
         class Builder {
 
-            private var country: JsonField<Country> = JsonMissing.of()
-            private var type: JsonField<Type> = JsonMissing.of()
-            private var value: JsonField<String> = JsonMissing.of()
+            private var country: JsonField<Country>? = null
+            private var type: JsonField<Type>? = null
+            private var value: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3005,9 +3442,9 @@ private constructor(
 
             fun build(): CustomerTaxId =
                 CustomerTaxId(
-                    country,
-                    type,
-                    value,
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(type) { "`type` is required but was not set" },
+                    checkNotNull(value) { "`value` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4413,33 +4850,39 @@ private constructor(
         fun taxAmounts(): List<TaxAmount> = taxAmounts.getRequired("tax_amounts")
 
         /** A unique ID for this line item. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The final amount after any discounts or minimums. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
         /** The end date of the range of time applied for this line item's price. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * [DEPRECATED] For configured prices that are split by a grouping key, this will be
          * populated with the key and a value. The `amount` and `subtotal` will be the values for
          * this particular grouping.
          */
-        @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+        @JsonProperty("grouping") @ExcludeMissing fun _grouping(): JsonField<String> = grouping
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The name of the price associated with this line item. */
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -4669,27 +5112,33 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
         /** The start date of the range of time applied for this line item's price. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         /**
          * For complex pricing structures, the line item can be broken down further in
          * `sub_line_items`.
          */
-        @JsonProperty("sub_line_items") @ExcludeMissing fun _subLineItems() = subLineItems
+        @JsonProperty("sub_line_items")
+        @ExcludeMissing
+        fun _subLineItems(): JsonField<List<SubLineItem>> = subLineItems
 
         /** The line amount before any line item-specific discounts or minimums. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
         /**
          * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
          * configured.
          */
-        @JsonProperty("tax_amounts") @ExcludeMissing fun _taxAmounts() = taxAmounts
+        @JsonProperty("tax_amounts")
+        @ExcludeMissing
+        fun _taxAmounts(): JsonField<List<TaxAmount>> = taxAmounts
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4728,22 +5177,22 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var grouping: JsonField<String> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var subLineItems: JsonField<List<SubLineItem>> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var taxAmounts: JsonField<List<TaxAmount>> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var grouping: JsonField<String>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var price: JsonField<Price>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
+            private var subLineItems: JsonField<MutableList<SubLineItem>>? = null
+            private var subtotal: JsonField<String>? = null
+            private var taxAmounts: JsonField<MutableList<TaxAmount>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4761,9 +5210,9 @@ private constructor(
                 price = lineItem.price
                 quantity = lineItem.quantity
                 startDate = lineItem.startDate
-                subLineItems = lineItem.subLineItems
+                subLineItems = lineItem.subLineItems.map { it.toMutableList() }
                 subtotal = lineItem.subtotal
-                taxAmounts = lineItem.taxAmounts
+                taxAmounts = lineItem.taxAmounts.map { it.toMutableList() }
                 additionalProperties = lineItem.additionalProperties.toMutableMap()
             }
 
@@ -4779,10 +5228,24 @@ private constructor(
             /** The final amount after any discounts or minimums. */
             fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
             /** The end date of the range of time applied for this line item's price. */
             fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
 
@@ -4794,40 +5257,289 @@ private constructor(
              * populated with the key and a value. The `amount` and `subtotal` will be the values
              * for this particular grouping.
              */
-            fun grouping(grouping: String) = grouping(JsonField.of(grouping))
+            fun grouping(grouping: String?) = grouping(JsonField.ofNullable(grouping))
+
+            /**
+             * [DEPRECATED] For configured prices that are split by a grouping key, this will be
+             * populated with the key and a value. The `amount` and `subtotal` will be the values
+             * for this particular grouping.
+             */
+            fun grouping(grouping: Optional<String>) = grouping(grouping.orElse(null))
 
             /**
              * [DEPRECATED] For configured prices that are split by a grouping key, this will be
              * populated with the key and a value. The `amount` and `subtotal` will be the values
              * for this particular grouping.
              */
-            fun grouping(grouping: JsonField<String>) = apply { this.grouping = grouping }
-
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
-
-            fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
-
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
-
-            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
-                this.maximumAmount = maximumAmount
-            }
-
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
-
-            fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
-
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
-
-            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
-                this.minimumAmount = minimumAmount
-            }
-
-            /** The name of the price associated with this line item. */
-            fun name(name: String) = name(JsonField.of(name))
-
-            /** The name of the price associated with this line item. */
-            fun name(name: JsonField<String>) = apply { this.name = name }
+            fun grouping(grouping: JsonField<String>) = apply { this.grouping = grouping }
+
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
+
+            fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
+
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
+
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
+
+            fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
+
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
+
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
+            }
+
+            /** The name of the price associated with this line item. */
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price associated with this line item. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            /**
+             * The Price resource represents a price that can be billed on a subscription, resulting
+             * in a charge on an invoice in the form of an invoice line item. Prices take a quantity
+             * and determine an amount to bill.
+             *
+             * Orb supports a few different pricing models out of the box. Each of these models is
+             * serialized differently in a given Price object. The model_type field determines the
+             * key for the configuration object that is present.
+             *
+             * ## Unit pricing
+             *
+             * With unit pricing, each unit costs a fixed amount.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "unit",
+             *     "unit_config": {
+             *         "unit_amount": "0.50"
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Tiered pricing
+             *
+             * In tiered pricing, the cost of a given unit depends on the tier range that it falls
+             * into, where each tier range is defined by an upper and lower bound. For example, the
+             * first ten units may cost $0.50 each and all units thereafter may cost $0.10 each.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "tiered",
+             *     "tiered_config": {
+             *         "tiers": [
+             *             {
+             *                 "first_unit": 1,
+             *                 "last_unit": 10,
+             *                 "unit_amount": "0.50"
+             *             },
+             *             {
+             *                 "first_unit": 11,
+             *                 "last_unit": null,
+             *                 "unit_amount": "0.10"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * ```
+             *
+             * ## Bulk pricing
+             *
+             * Bulk pricing applies when the number of units determine the cost of all units. For
+             * example, if you've bought less than 10 units, they may each be $0.50 for a total of
+             * $5.00. Once you've bought more than 10 units, all units may now be priced at $0.40
+             * (i.e. 101 units total would be $40.40).
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "bulk",
+             *     "bulk_config": {
+             *         "tiers": [
+             *             {
+             *                 "maximum_units": 10,
+             *                 "unit_amount": "0.50"
+             *             },
+             *             {
+             *                 "maximum_units": 1000,
+             *                 "unit_amount": "0.40"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Package pricing
+             *
+             * Package pricing defines the size or granularity of a unit for billing purposes. For
+             * example, if the package size is set to 5, then 4 units will be billed as 5 and 6
+             * units will be billed at 10.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "package",
+             *     "package_config": {
+             *         "package_amount": "0.80",
+             *         "package_size": 10
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## BPS pricing
+             *
+             * BPS pricing specifies a per-event (e.g. per-payment) rate in one hundredth of a
+             * percent (the number of basis points to charge), as well as a cap per event to assess.
+             * For example, this would allow you to assess a fee of 0.25% on every payment you
+             * process, with a maximum charge of $25 per payment.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "model_type": "bps",
+             *     "bps_config": {
+             *        "bps": 125,
+             *        "per_unit_maximum": "11.00"
+             *     }
+             *     ...
+             *  }
+             * ```
+             *
+             * ## Bulk BPS pricing
+             *
+             * Bulk BPS pricing specifies BPS parameters in a tiered manner, dependent on the total
+             * quantity across all events. Similar to bulk pricing, the BPS parameters of a given
+             * event depends on the tier range that the billing period falls into. Each tier range
+             * is defined by an upper bound. For example, after $1.5M of payment volume is reached,
+             * each individual payment may have a lower cap or a smaller take-rate.
+             *
+             * ```json
+             *     ...
+             *     "model_type": "bulk_bps",
+             *     "bulk_bps_config": {
+             *         "tiers": [
+             *            {
+             *                 "maximum_amount": "1000000.00",
+             *                 "bps": 125,
+             *                 "per_unit_maximum": "19.00"
+             *            },
+             *           {
+             *                 "maximum_amount": null,
+             *                 "bps": 115,
+             *                 "per_unit_maximum": "4.00"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Tiered BPS pricing
+             *
+             * Tiered BPS pricing specifies BPS parameters in a graduated manner, where an event's
+             * applicable parameter is a function of its marginal addition to the period total.
+             * Similar to tiered pricing, the BPS parameters of a given event depends on the tier
+             * range that it falls into, where each tier range is defined by an upper and lower
+             * bound. For example, the first few payments may have a 0.8 BPS take-rate and all
+             * payments after a specific volume may incur a take-rate of 0.5 BPS each.
+             *
+             * ```json
+             *     ...
+             *     "model_type": "tiered_bps",
+             *     "tiered_bps_config": {
+             *         "tiers": [
+             *            {
+             *                 "minimum_amount": "0",
+             *                 "maximum_amount": "1000000.00",
+             *                 "bps": 125,
+             *                 "per_unit_maximum": "19.00"
+             *            },
+             *           {
+             *                 "minimum_amount": "1000000.00",
+             *                 "maximum_amount": null,
+             *                 "bps": 115,
+             *                 "per_unit_maximum": "4.00"
+             *             }
+             *         ]
+             *     }
+             *     ...
+             * }
+             * ```
+             *
+             * ## Matrix pricing
+             *
+             * Matrix pricing defines a set of unit prices in a one or two-dimensional matrix.
+             * `dimensions` defines the two event property values evaluated in this pricing model.
+             * In a one-dimensional matrix, the second value is `null`. Every configuration has a
+             * list of `matrix_values` which give the unit prices for specified property values. In
+             * a one-dimensional matrix, the matrix values will have `dimension_values` where the
+             * second value of the pair is null. If an event does not match any of the dimension
+             * values in the matrix, it will resort to the `default_unit_amount`.
+             *
+             * ```json
+             * {
+             *     "model_type": "matrix"
+             *     "matrix_config": {
+             *         "default_unit_amount": "3.00",
+             *         "dimensions": [
+             *             "cluster_name",
+             *             "region"
+             *         ],
+             *         "matrix_values": [
+             *             {
+             *                 "dimension_values": [
+             *                     "alpha",
+             *                     "west"
+             *                 ],
+             *                 "unit_amount": "2.00"
+             *             },
+             *             ...
+             *         ]
+             *     }
+             * }
+             * ```
+             *
+             * ## Fixed fees
+             *
+             * Fixed fees are prices that are applied independent of usage quantities, and follow
+             * unit pricing. They also have an additional parameter `fixed_price_quantity`. If the
+             * Price represents a fixed cost, this represents the quantity of units applied.
+             *
+             * ```json
+             * {
+             *     ...
+             *     "id": "price_id",
+             *     "model_type": "unit",
+             *     "unit_config": {
+             *        "unit_amount": "2.00"
+             *     },
+             *     "fixed_price_quantity": 3.0
+             *     ...
+             * }
+             * ```
+             */
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5057,7 +5769,7 @@ private constructor(
              * }
              * ```
              */
-            fun price(price: Price) = price(JsonField.of(price))
+            fun price(price: Optional<Price>) = price(price.orElse(null))
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5289,6 +6001,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
 
             fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -5313,7 +6090,24 @@ private constructor(
              * `sub_line_items`.
              */
             fun subLineItems(subLineItems: JsonField<List<SubLineItem>>) = apply {
-                this.subLineItems = subLineItems
+                this.subLineItems = subLineItems.map { it.toMutableList() }
+            }
+
+            /**
+             * For complex pricing structures, the line item can be broken down further in
+             * `sub_line_items`.
+             */
+            fun addSubLineItem(subLineItem: SubLineItem) = apply {
+                subLineItems =
+                    (subLineItems ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(subLineItem)
+                    }
             }
 
             /** The line amount before any line item-specific discounts or minimums. */
@@ -5333,7 +6127,24 @@ private constructor(
              * configured.
              */
             fun taxAmounts(taxAmounts: JsonField<List<TaxAmount>>) = apply {
-                this.taxAmounts = taxAmounts
+                this.taxAmounts = taxAmounts.map { it.toMutableList() }
+            }
+
+            /**
+             * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
+             * configured.
+             */
+            fun addTaxAmount(taxAmount: TaxAmount) = apply {
+                taxAmounts =
+                    (taxAmounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(taxAmount)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -5357,22 +6168,24 @@ private constructor(
 
             fun build(): LineItem =
                 LineItem(
-                    id,
-                    amount,
-                    discount,
-                    endDate,
-                    grouping,
-                    maximum,
-                    maximumAmount,
-                    minimum,
-                    minimumAmount,
-                    name,
-                    price,
-                    quantity,
-                    startDate,
-                    subLineItems.map { it.toImmutable() },
-                    subtotal,
-                    taxAmounts.map { it.toImmutable() },
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(grouping) { "`grouping` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
+                    checkNotNull(subLineItems) { "`subLineItems` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(taxAmounts) { "`taxAmounts` is required but was not set" }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5407,10 +6220,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5435,13 +6250,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -5458,7 +6273,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -5494,8 +6326,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5548,10 +6385,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5576,13 +6415,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -5599,7 +6438,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -5635,8 +6491,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5865,17 +6726,23 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("matrix_config") @ExcludeMissing fun _matrixConfig() = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -5904,12 +6771,12 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var matrixConfig: JsonField<MatrixConfig> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5929,7 +6796,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -5976,12 +6845,14 @@ private constructor(
 
                     fun build(): MatrixSubLineItem =
                         MatrixSubLineItem(
-                            amount,
-                            grouping,
-                            matrixConfig,
-                            name,
-                            quantity,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(matrixConfig) {
+                                "`matrixConfig` is required but was not set"
+                            },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6005,10 +6876,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6033,8 +6904,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6050,7 +6921,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -6079,8 +6953,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6121,7 +6995,7 @@ private constructor(
                     /** The ordered dimension values for this line item. */
                     @JsonProperty("dimension_values")
                     @ExcludeMissing
-                    fun _dimensionValues() = dimensionValues
+                    fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6145,13 +7019,14 @@ private constructor(
 
                     class Builder {
 
-                        private var dimensionValues: JsonField<List<String?>> = JsonMissing.of()
+                        private var dimensionValues: JsonField<MutableList<String?>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
-                            dimensionValues = matrixConfig.dimensionValues
+                            dimensionValues =
+                                matrixConfig.dimensionValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -6161,7 +7036,21 @@ private constructor(
 
                         /** The ordered dimension values for this line item. */
                         fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
-                            this.dimensionValues = dimensionValues
+                            this.dimensionValues = dimensionValues.map { it.toMutableList() }
+                        }
+
+                        /** The ordered dimension values for this line item. */
+                        fun addDimensionValue(dimensionValue: String) = apply {
+                            dimensionValues =
+                                (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimensionValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -6188,7 +7077,10 @@ private constructor(
 
                         fun build(): MatrixConfig =
                             MatrixConfig(
-                                dimensionValues.map { it.toImmutable() },
+                                checkNotNull(dimensionValues) {
+                                        "`dimensionValues` is required but was not set"
+                                    }
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -6322,17 +7214,23 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("tier_config") @ExcludeMissing fun _tierConfig() = tierConfig
+                @JsonProperty("tier_config")
+                @ExcludeMissing
+                fun _tierConfig(): JsonField<TierConfig> = tierConfig
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -6361,12 +7259,12 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var tierConfig: JsonField<TierConfig> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var tierConfig: JsonField<TierConfig>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6386,7 +7284,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -6432,12 +7332,12 @@ private constructor(
 
                     fun build(): TierSubLineItem =
                         TierSubLineItem(
-                            amount,
-                            grouping,
-                            name,
-                            quantity,
-                            tierConfig,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(tierConfig) { "`tierConfig` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6461,10 +7361,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6489,8 +7389,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6506,7 +7406,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -6535,8 +7438,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6583,11 +7486,17 @@ private constructor(
 
                     fun unitAmount(): String = unitAmount.getRequired("unit_amount")
 
-                    @JsonProperty("first_unit") @ExcludeMissing fun _firstUnit() = firstUnit
+                    @JsonProperty("first_unit")
+                    @ExcludeMissing
+                    fun _firstUnit(): JsonField<Double> = firstUnit
 
-                    @JsonProperty("last_unit") @ExcludeMissing fun _lastUnit() = lastUnit
+                    @JsonProperty("last_unit")
+                    @ExcludeMissing
+                    fun _lastUnit(): JsonField<Double> = lastUnit
 
-                    @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6613,9 +7522,9 @@ private constructor(
 
                     class Builder {
 
-                        private var firstUnit: JsonField<Double> = JsonMissing.of()
-                        private var lastUnit: JsonField<Double> = JsonMissing.of()
-                        private var unitAmount: JsonField<String> = JsonMissing.of()
+                        private var firstUnit: JsonField<Double>? = null
+                        private var lastUnit: JsonField<Double>? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6633,7 +7542,15 @@ private constructor(
                             this.firstUnit = firstUnit
                         }
 
-                        fun lastUnit(lastUnit: Double) = lastUnit(JsonField.of(lastUnit))
+                        fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
+
+                        fun lastUnit(lastUnit: Double) = lastUnit(lastUnit as Double?)
+
+                        @Suppress(
+                            "USELESS_CAST"
+                        ) // See https://youtrack.jetbrains.com/issue/KT-74228
+                        fun lastUnit(lastUnit: Optional<Double>) =
+                            lastUnit(lastUnit.orElse(null) as Double?)
 
                         fun lastUnit(lastUnit: JsonField<Double>) = apply {
                             this.lastUnit = lastUnit
@@ -6669,9 +7586,13 @@ private constructor(
 
                         fun build(): TierConfig =
                             TierConfig(
-                                firstUnit,
-                                lastUnit,
-                                unitAmount,
+                                checkNotNull(firstUnit) {
+                                    "`firstUnit` is required but was not set"
+                                },
+                                checkNotNull(lastUnit) { "`lastUnit` is required but was not set" },
+                                checkNotNull(unitAmount) {
+                                    "`unitAmount` is required but was not set"
+                                },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6800,15 +7721,19 @@ private constructor(
                 fun type(): Type = type.getRequired("type")
 
                 /** The total amount for this sub line item. */
-                @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+                @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-                @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+                @JsonProperty("grouping")
+                @ExcludeMissing
+                fun _grouping(): JsonField<Grouping> = grouping
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("type") @ExcludeMissing fun _type() = type
+                @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -6836,11 +7761,11 @@ private constructor(
 
                 class Builder {
 
-                    private var amount: JsonField<String> = JsonMissing.of()
-                    private var grouping: JsonField<Grouping> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var type: JsonField<Type> = JsonMissing.of()
+                    private var amount: JsonField<String>? = null
+                    private var grouping: JsonField<Grouping>? = null
+                    private var name: JsonField<String>? = null
+                    private var quantity: JsonField<Double>? = null
+                    private var type: JsonField<Type>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6859,7 +7784,9 @@ private constructor(
                     /** The total amount for this sub line item. */
                     fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                    fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                    fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                    fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                     fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -6899,11 +7826,11 @@ private constructor(
 
                     fun build(): OtherSubLineItem =
                         OtherSubLineItem(
-                            amount,
-                            grouping,
-                            name,
-                            quantity,
-                            type,
+                            checkNotNull(amount) { "`amount` is required but was not set" },
+                            checkNotNull(grouping) { "`grouping` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(type) { "`type` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6927,10 +7854,10 @@ private constructor(
                     /** No value indicates the default group */
                     fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                    @JsonProperty("key") @ExcludeMissing fun _key() = key
+                    @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                     /** No value indicates the default group */
-                    @JsonProperty("value") @ExcludeMissing fun _value() = value
+                    @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                     @JsonAnyGetter
                     @ExcludeMissing
@@ -6955,8 +7882,8 @@ private constructor(
 
                     class Builder {
 
-                        private var key: JsonField<String> = JsonMissing.of()
-                        private var value: JsonField<String> = JsonMissing.of()
+                        private var key: JsonField<String>? = null
+                        private var value: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6972,7 +7899,10 @@ private constructor(
                         fun key(key: JsonField<String>) = apply { this.key = key }
 
                         /** No value indicates the default group */
-                        fun value(value: String) = value(JsonField.of(value))
+                        fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                        /** No value indicates the default group */
+                        fun value(value: Optional<String>) = value(value.orElse(null))
 
                         /** No value indicates the default group */
                         fun value(value: JsonField<String>) = apply { this.value = value }
@@ -7001,8 +7931,8 @@ private constructor(
 
                         fun build(): Grouping =
                             Grouping(
-                                key,
-                                value,
+                                checkNotNull(key) { "`key` is required but was not set" },
+                                checkNotNull(value) { "`value` is required but was not set" },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -7125,17 +8055,17 @@ private constructor(
                 Optional.ofNullable(taxRatePercentage.getNullable("tax_rate_percentage"))
 
             /** The amount of additional tax incurred by this tax rate. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
             /** The human-readable description of the applied tax rate. */
             @JsonProperty("tax_rate_description")
             @ExcludeMissing
-            fun _taxRateDescription() = taxRateDescription
+            fun _taxRateDescription(): JsonField<String> = taxRateDescription
 
             /** The tax rate percentage, out of 100. */
             @JsonProperty("tax_rate_percentage")
             @ExcludeMissing
-            fun _taxRatePercentage() = taxRatePercentage
+            fun _taxRatePercentage(): JsonField<String> = taxRatePercentage
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7161,9 +8091,9 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var taxRateDescription: JsonField<String> = JsonMissing.of()
-                private var taxRatePercentage: JsonField<String> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var taxRateDescription: JsonField<String>? = null
+                private var taxRatePercentage: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7190,8 +8120,12 @@ private constructor(
                 }
 
                 /** The tax rate percentage, out of 100. */
-                fun taxRatePercentage(taxRatePercentage: String) =
-                    taxRatePercentage(JsonField.of(taxRatePercentage))
+                fun taxRatePercentage(taxRatePercentage: String?) =
+                    taxRatePercentage(JsonField.ofNullable(taxRatePercentage))
+
+                /** The tax rate percentage, out of 100. */
+                fun taxRatePercentage(taxRatePercentage: Optional<String>) =
+                    taxRatePercentage(taxRatePercentage.orElse(null))
 
                 /** The tax rate percentage, out of 100. */
                 fun taxRatePercentage(taxRatePercentage: JsonField<String>) = apply {
@@ -7222,9 +8156,13 @@ private constructor(
 
                 fun build(): TaxAmount =
                     TaxAmount(
-                        amount,
-                        taxRateDescription,
-                        taxRatePercentage,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(taxRateDescription) {
+                            "`taxRateDescription` is required but was not set"
+                        },
+                        checkNotNull(taxRatePercentage) {
+                            "`taxRatePercentage` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7295,10 +8233,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Maximum amount applied */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7323,13 +8263,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var maximumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximum: Maximum) = apply {
-                appliesToPriceIds = maximum.appliesToPriceIds
+                appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                 maximumAmount = maximum.maximumAmount
                 additionalProperties = maximum.additionalProperties.toMutableMap()
             }
@@ -7346,7 +8286,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this maximum amount applies to. For plan/plan phase maximums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Maximum amount applied */
@@ -7378,8 +8335,11 @@ private constructor(
 
             fun build(): Maximum =
                 Maximum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    maximumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7512,10 +8472,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Minimum amount applied */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7540,13 +8502,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var minimumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimum: Minimum) = apply {
-                appliesToPriceIds = minimum.appliesToPriceIds
+                appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                 minimumAmount = minimum.minimumAmount
                 additionalProperties = minimum.additionalProperties.toMutableMap()
             }
@@ -7563,7 +8525,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this minimum amount applies to. For plan/plan phase minimums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Minimum amount applied */
@@ -7595,8 +8574,11 @@ private constructor(
 
             fun build(): Minimum =
                 Minimum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    minimumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7664,24 +8646,28 @@ private constructor(
         fun succeeded(): Boolean = succeeded.getRequired("succeeded")
 
         /** The ID of the payment attempt. */
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The amount of the payment attempt. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The time at which the payment attempt was created. */
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         /** The payment provider that attempted to collect the payment. */
-        @JsonProperty("payment_provider") @ExcludeMissing fun _paymentProvider() = paymentProvider
+        @JsonProperty("payment_provider")
+        @ExcludeMissing
+        fun _paymentProvider(): JsonField<PaymentProvider> = paymentProvider
 
         /** The ID of the payment attempt in the payment provider. */
         @JsonProperty("payment_provider_id")
         @ExcludeMissing
-        fun _paymentProviderId() = paymentProviderId
+        fun _paymentProviderId(): JsonField<String> = paymentProviderId
 
         /** Whether the payment attempt succeeded. */
-        @JsonProperty("succeeded") @ExcludeMissing fun _succeeded() = succeeded
+        @JsonProperty("succeeded") @ExcludeMissing fun _succeeded(): JsonField<Boolean> = succeeded
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7710,12 +8696,12 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var paymentProvider: JsonField<PaymentProvider> = JsonMissing.of()
-            private var paymentProviderId: JsonField<String> = JsonMissing.of()
-            private var succeeded: JsonField<Boolean> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var amount: JsonField<String>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var paymentProvider: JsonField<PaymentProvider>? = null
+            private var paymentProviderId: JsonField<String>? = null
+            private var succeeded: JsonField<Boolean>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -7750,8 +8736,12 @@ private constructor(
             }
 
             /** The payment provider that attempted to collect the payment. */
-            fun paymentProvider(paymentProvider: PaymentProvider) =
-                paymentProvider(JsonField.of(paymentProvider))
+            fun paymentProvider(paymentProvider: PaymentProvider?) =
+                paymentProvider(JsonField.ofNullable(paymentProvider))
+
+            /** The payment provider that attempted to collect the payment. */
+            fun paymentProvider(paymentProvider: Optional<PaymentProvider>) =
+                paymentProvider(paymentProvider.orElse(null))
 
             /** The payment provider that attempted to collect the payment. */
             fun paymentProvider(paymentProvider: JsonField<PaymentProvider>) = apply {
@@ -7759,8 +8749,12 @@ private constructor(
             }
 
             /** The ID of the payment attempt in the payment provider. */
-            fun paymentProviderId(paymentProviderId: String) =
-                paymentProviderId(JsonField.of(paymentProviderId))
+            fun paymentProviderId(paymentProviderId: String?) =
+                paymentProviderId(JsonField.ofNullable(paymentProviderId))
+
+            /** The ID of the payment attempt in the payment provider. */
+            fun paymentProviderId(paymentProviderId: Optional<String>) =
+                paymentProviderId(paymentProviderId.orElse(null))
 
             /** The ID of the payment attempt in the payment provider. */
             fun paymentProviderId(paymentProviderId: JsonField<String>) = apply {
@@ -7794,12 +8788,16 @@ private constructor(
 
             fun build(): PaymentAttempt =
                 PaymentAttempt(
-                    id,
-                    amount,
-                    createdAt,
-                    paymentProvider,
-                    paymentProviderId,
-                    succeeded,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(paymentProvider) {
+                        "`paymentProvider` is required but was not set"
+                    },
+                    checkNotNull(paymentProviderId) {
+                        "`paymentProviderId` is required but was not set"
+                    },
+                    checkNotNull(succeeded) { "`succeeded` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7912,17 +8910,19 @@ private constructor(
 
         fun state(): Optional<String> = Optional.ofNullable(state.getNullable("state"))
 
-        @JsonProperty("city") @ExcludeMissing fun _city() = city
+        @JsonProperty("city") @ExcludeMissing fun _city(): JsonField<String> = city
 
-        @JsonProperty("country") @ExcludeMissing fun _country() = country
+        @JsonProperty("country") @ExcludeMissing fun _country(): JsonField<String> = country
 
-        @JsonProperty("line1") @ExcludeMissing fun _line1() = line1
+        @JsonProperty("line1") @ExcludeMissing fun _line1(): JsonField<String> = line1
 
-        @JsonProperty("line2") @ExcludeMissing fun _line2() = line2
+        @JsonProperty("line2") @ExcludeMissing fun _line2(): JsonField<String> = line2
 
-        @JsonProperty("postal_code") @ExcludeMissing fun _postalCode() = postalCode
+        @JsonProperty("postal_code")
+        @ExcludeMissing
+        fun _postalCode(): JsonField<String> = postalCode
 
-        @JsonProperty("state") @ExcludeMissing fun _state() = state
+        @JsonProperty("state") @ExcludeMissing fun _state(): JsonField<String> = state
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -7951,12 +8951,12 @@ private constructor(
 
         class Builder {
 
-            private var city: JsonField<String> = JsonMissing.of()
-            private var country: JsonField<String> = JsonMissing.of()
-            private var line1: JsonField<String> = JsonMissing.of()
-            private var line2: JsonField<String> = JsonMissing.of()
-            private var postalCode: JsonField<String> = JsonMissing.of()
-            private var state: JsonField<String> = JsonMissing.of()
+            private var city: JsonField<String>? = null
+            private var country: JsonField<String>? = null
+            private var line1: JsonField<String>? = null
+            private var line2: JsonField<String>? = null
+            private var postalCode: JsonField<String>? = null
+            private var state: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -7970,27 +8970,39 @@ private constructor(
                 additionalProperties = shippingAddress.additionalProperties.toMutableMap()
             }
 
-            fun city(city: String) = city(JsonField.of(city))
+            fun city(city: String?) = city(JsonField.ofNullable(city))
+
+            fun city(city: Optional<String>) = city(city.orElse(null))
 
             fun city(city: JsonField<String>) = apply { this.city = city }
 
-            fun country(country: String) = country(JsonField.of(country))
+            fun country(country: String?) = country(JsonField.ofNullable(country))
+
+            fun country(country: Optional<String>) = country(country.orElse(null))
 
             fun country(country: JsonField<String>) = apply { this.country = country }
 
-            fun line1(line1: String) = line1(JsonField.of(line1))
+            fun line1(line1: String?) = line1(JsonField.ofNullable(line1))
+
+            fun line1(line1: Optional<String>) = line1(line1.orElse(null))
 
             fun line1(line1: JsonField<String>) = apply { this.line1 = line1 }
 
-            fun line2(line2: String) = line2(JsonField.of(line2))
+            fun line2(line2: String?) = line2(JsonField.ofNullable(line2))
+
+            fun line2(line2: Optional<String>) = line2(line2.orElse(null))
 
             fun line2(line2: JsonField<String>) = apply { this.line2 = line2 }
 
-            fun postalCode(postalCode: String) = postalCode(JsonField.of(postalCode))
+            fun postalCode(postalCode: String?) = postalCode(JsonField.ofNullable(postalCode))
+
+            fun postalCode(postalCode: Optional<String>) = postalCode(postalCode.orElse(null))
 
             fun postalCode(postalCode: JsonField<String>) = apply { this.postalCode = postalCode }
 
-            fun state(state: String) = state(JsonField.of(state))
+            fun state(state: String?) = state(JsonField.ofNullable(state))
+
+            fun state(state: Optional<String>) = state(state.orElse(null))
 
             fun state(state: JsonField<String>) = apply { this.state = state }
 
@@ -8015,12 +9027,12 @@ private constructor(
 
             fun build(): ShippingAddress =
                 ShippingAddress(
-                    city,
-                    country,
-                    line1,
-                    line2,
-                    postalCode,
-                    state,
+                    checkNotNull(city) { "`city` is required but was not set" },
+                    checkNotNull(country) { "`country` is required but was not set" },
+                    checkNotNull(line1) { "`line1` is required but was not set" },
+                    checkNotNull(line2) { "`line2` is required but was not set" },
+                    checkNotNull(postalCode) { "`postalCode` is required but was not set" },
+                    checkNotNull(state) { "`state` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -8129,7 +9141,7 @@ private constructor(
 
         fun id(): String = id.getRequired("id")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -8153,7 +9165,7 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -8185,7 +9197,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): Subscription = Subscription(id, additionalProperties.toImmutable())
+            fun build(): Subscription =
+                Subscription(
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceIssueParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceIssueParams.kt
index 7d0e65cf..f6695566 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceIssueParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceIssueParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,13 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows an eligible invoice to be issued manually. This is only possible with
+ * invoices where status is `draft`, `will_auto_issue` is false, and an `eligible_to_issue_at` is a
+ * time in the past. Issuing an invoice could possibly trigger side effects, some of which could be
+ * customer-visible (e.g. sending emails, auto-collecting payment, syncing the invoice to external
+ * providers, etc).
+ */
 class InvoiceIssueParams
 constructor(
     private val invoiceId: String,
@@ -34,12 +43,20 @@ constructor(
      */
     fun synchronous(): Optional<Boolean> = body.synchronous()
 
+    /**
+     * If true, the invoice will be issued synchronously. If false, the invoice will be issued
+     * asynchronously. The synchronous option is only available for invoices containin no usage
+     * fees. If the invoice is configured to sync to an external provider, a successful response
+     * from this endpoint guarantees the invoice is present in the provider.
+     */
+    fun _synchronous(): JsonField<Boolean> = body._synchronous()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): InvoiceIssueBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -57,11 +74,22 @@ constructor(
     class InvoiceIssueBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("synchronous") private val synchronous: Boolean?,
+        @JsonProperty("synchronous")
+        @ExcludeMissing
+        private val synchronous: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * If true, the invoice will be issued synchronously. If false, the invoice will be issued
+         * asynchronously. The synchronous option is only available for invoices containin no usage
+         * fees. If the invoice is configured to sync to an external provider, a successful response
+         * from this endpoint guarantees the invoice is present in the provider.
+         */
+        fun synchronous(): Optional<Boolean> =
+            Optional.ofNullable(synchronous.getNullable("synchronous"))
+
         /**
          * If true, the invoice will be issued synchronously. If false, the invoice will be issued
          * asynchronously. The synchronous option is only available for invoices containin no usage
@@ -69,12 +97,22 @@ constructor(
          * from this endpoint guarantees the invoice is present in the provider.
          */
         @JsonProperty("synchronous")
-        fun synchronous(): Optional<Boolean> = Optional.ofNullable(synchronous)
+        @ExcludeMissing
+        fun _synchronous(): JsonField<Boolean> = synchronous
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceIssueBody = apply {
+            if (!validated) {
+                synchronous()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -84,7 +122,7 @@ constructor(
 
         class Builder {
 
-            private var synchronous: Boolean? = null
+            private var synchronous: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -100,7 +138,7 @@ constructor(
              * provider, a successful response from this endpoint guarantees the invoice is present
              * in the provider.
              */
-            fun synchronous(synchronous: Boolean?) = apply { this.synchronous = synchronous }
+            fun synchronous(synchronous: Boolean) = synchronous(JsonField.of(synchronous))
 
             /**
              * If true, the invoice will be issued synchronously. If false, the invoice will be
@@ -109,18 +147,9 @@ constructor(
              * provider, a successful response from this endpoint guarantees the invoice is present
              * in the provider.
              */
-            fun synchronous(synchronous: Boolean) = synchronous(synchronous as Boolean?)
-
-            /**
-             * If true, the invoice will be issued synchronously. If false, the invoice will be
-             * issued asynchronously. The synchronous option is only available for invoices
-             * containin no usage fees. If the invoice is configured to sync to an external
-             * provider, a successful response from this endpoint guarantees the invoice is present
-             * in the provider.
-             */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun synchronous(synchronous: Optional<Boolean>) =
-                synchronous(synchronous.orElse(null) as Boolean?)
+            fun synchronous(synchronous: JsonField<Boolean>) = apply {
+                this.synchronous = synchronous
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -194,7 +223,7 @@ constructor(
          * fees. If the invoice is configured to sync to an external provider, a successful response
          * from this endpoint guarantees the invoice is present in the provider.
          */
-        fun synchronous(synchronous: Boolean?) = apply { body.synchronous(synchronous) }
+        fun synchronous(synchronous: Boolean) = apply { body.synchronous(synchronous) }
 
         /**
          * If true, the invoice will be issued synchronously. If false, the invoice will be issued
@@ -202,17 +231,26 @@ constructor(
          * fees. If the invoice is configured to sync to an external provider, a successful response
          * from this endpoint guarantees the invoice is present in the provider.
          */
-        fun synchronous(synchronous: Boolean) = synchronous(synchronous as Boolean?)
+        fun synchronous(synchronous: JsonField<Boolean>) = apply { body.synchronous(synchronous) }
 
-        /**
-         * If true, the invoice will be issued synchronously. If false, the invoice will be issued
-         * asynchronously. The synchronous option is only available for invoices containin no usage
-         * fees. If the invoice is configured to sync to an external provider, a successful response
-         * from this endpoint guarantees the invoice is present in the provider.
-         */
-        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-        fun synchronous(synchronous: Optional<Boolean>) =
-            synchronous(synchronous.orElse(null) as Boolean?)
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -312,25 +350,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): InvoiceIssueParams =
             InvoiceIssueParams(
                 checkNotNull(invoiceId) { "`invoiceId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateParams.kt
index a1975bec..c6accbed 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,10 @@ import com.withorb.api.core.toImmutable
 import java.time.LocalDate
 import java.util.Objects
 
+/**
+ * This creates a one-off fixed fee invoice line item on an Invoice. This can only be done for
+ * invoices that are in a `draft` status.
+ */
 class InvoiceLineItemCreateParams
 constructor(
     private val body: InvoiceLineItemCreateBody,
@@ -44,12 +50,33 @@ constructor(
     /** A date string to specify the line item's start date in the customer's timezone. */
     fun startDate(): LocalDate = body.startDate()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The total amount in the invoice's currency to add to the line item. */
+    fun _amount(): JsonField<String> = body._amount()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** A date string to specify the line item's end date in the customer's timezone. */
+    fun _endDate(): JsonField<LocalDate> = body._endDate()
+
+    /** The id of the Invoice to add this line item. */
+    fun _invoiceId(): JsonField<String> = body._invoiceId()
+
+    /**
+     * The item name associated with this line item. If an item with the same name exists in Orb,
+     * that item will be associated with the line item.
+     */
+    fun _name(): JsonField<String> = body._name()
+
+    /** The number of units on the line item */
+    fun _quantity(): JsonField<Double> = body._quantity()
+
+    /** A date string to specify the line item's start date in the customer's timezone. */
+    fun _startDate(): JsonField<LocalDate> = body._startDate()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): InvoiceLineItemCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -60,41 +87,90 @@ constructor(
     class InvoiceLineItemCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("amount") private val amount: String,
-        @JsonProperty("end_date") private val endDate: LocalDate,
-        @JsonProperty("invoice_id") private val invoiceId: String,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("quantity") private val quantity: Double,
-        @JsonProperty("start_date") private val startDate: LocalDate,
+        @JsonProperty("amount")
+        @ExcludeMissing
+        private val amount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("invoice_id")
+        @ExcludeMissing
+        private val invoiceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("quantity")
+        @ExcludeMissing
+        private val quantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<LocalDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The total amount in the invoice's currency to add to the line item. */
-        @JsonProperty("amount") fun amount(): String = amount
+        fun amount(): String = amount.getRequired("amount")
+
+        /** A date string to specify the line item's end date in the customer's timezone. */
+        fun endDate(): LocalDate = endDate.getRequired("end_date")
+
+        /** The id of the Invoice to add this line item. */
+        fun invoiceId(): String = invoiceId.getRequired("invoice_id")
+
+        /**
+         * The item name associated with this line item. If an item with the same name exists in
+         * Orb, that item will be associated with the line item.
+         */
+        fun name(): String = name.getRequired("name")
+
+        /** The number of units on the line item */
+        fun quantity(): Double = quantity.getRequired("quantity")
+
+        /** A date string to specify the line item's start date in the customer's timezone. */
+        fun startDate(): LocalDate = startDate.getRequired("start_date")
+
+        /** The total amount in the invoice's currency to add to the line item. */
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** A date string to specify the line item's end date in the customer's timezone. */
-        @JsonProperty("end_date") fun endDate(): LocalDate = endDate
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<LocalDate> = endDate
 
         /** The id of the Invoice to add this line item. */
-        @JsonProperty("invoice_id") fun invoiceId(): String = invoiceId
+        @JsonProperty("invoice_id") @ExcludeMissing fun _invoiceId(): JsonField<String> = invoiceId
 
         /**
          * The item name associated with this line item. If an item with the same name exists in
          * Orb, that item will be associated with the line item.
          */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The number of units on the line item */
-        @JsonProperty("quantity") fun quantity(): Double = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
         /** A date string to specify the line item's start date in the customer's timezone. */
-        @JsonProperty("start_date") fun startDate(): LocalDate = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<LocalDate> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceLineItemCreateBody = apply {
+            if (!validated) {
+                amount()
+                endDate()
+                invoiceId()
+                name()
+                quantity()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -104,12 +180,12 @@ constructor(
 
         class Builder {
 
-            private var amount: String? = null
-            private var endDate: LocalDate? = null
-            private var invoiceId: String? = null
-            private var name: String? = null
-            private var quantity: Double? = null
-            private var startDate: LocalDate? = null
+            private var amount: JsonField<String>? = null
+            private var endDate: JsonField<LocalDate>? = null
+            private var invoiceId: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<LocalDate>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -124,25 +200,46 @@ constructor(
             }
 
             /** The total amount in the invoice's currency to add to the line item. */
-            fun amount(amount: String) = apply { this.amount = amount }
+            fun amount(amount: String) = amount(JsonField.of(amount))
+
+            /** The total amount in the invoice's currency to add to the line item. */
+            fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
             /** A date string to specify the line item's end date in the customer's timezone. */
-            fun endDate(endDate: LocalDate) = apply { this.endDate = endDate }
+            fun endDate(endDate: LocalDate) = endDate(JsonField.of(endDate))
+
+            /** A date string to specify the line item's end date in the customer's timezone. */
+            fun endDate(endDate: JsonField<LocalDate>) = apply { this.endDate = endDate }
+
+            /** The id of the Invoice to add this line item. */
+            fun invoiceId(invoiceId: String) = invoiceId(JsonField.of(invoiceId))
 
             /** The id of the Invoice to add this line item. */
-            fun invoiceId(invoiceId: String) = apply { this.invoiceId = invoiceId }
+            fun invoiceId(invoiceId: JsonField<String>) = apply { this.invoiceId = invoiceId }
 
             /**
              * The item name associated with this line item. If an item with the same name exists in
              * Orb, that item will be associated with the line item.
              */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /**
+             * The item name associated with this line item. If an item with the same name exists in
+             * Orb, that item will be associated with the line item.
+             */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            /** The number of units on the line item */
+            fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
 
             /** The number of units on the line item */
-            fun quantity(quantity: Double) = apply { this.quantity = quantity }
+            fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
+
+            /** A date string to specify the line item's start date in the customer's timezone. */
+            fun startDate(startDate: LocalDate) = startDate(JsonField.of(startDate))
 
             /** A date string to specify the line item's start date in the customer's timezone. */
-            fun startDate(startDate: LocalDate) = apply { this.startDate = startDate }
+            fun startDate(startDate: JsonField<LocalDate>) = apply { this.startDate = startDate }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -217,24 +314,64 @@ constructor(
         /** The total amount in the invoice's currency to add to the line item. */
         fun amount(amount: String) = apply { body.amount(amount) }
 
+        /** The total amount in the invoice's currency to add to the line item. */
+        fun amount(amount: JsonField<String>) = apply { body.amount(amount) }
+
         /** A date string to specify the line item's end date in the customer's timezone. */
         fun endDate(endDate: LocalDate) = apply { body.endDate(endDate) }
 
+        /** A date string to specify the line item's end date in the customer's timezone. */
+        fun endDate(endDate: JsonField<LocalDate>) = apply { body.endDate(endDate) }
+
         /** The id of the Invoice to add this line item. */
         fun invoiceId(invoiceId: String) = apply { body.invoiceId(invoiceId) }
 
+        /** The id of the Invoice to add this line item. */
+        fun invoiceId(invoiceId: JsonField<String>) = apply { body.invoiceId(invoiceId) }
+
         /**
          * The item name associated with this line item. If an item with the same name exists in
          * Orb, that item will be associated with the line item.
          */
         fun name(name: String) = apply { body.name(name) }
 
+        /**
+         * The item name associated with this line item. If an item with the same name exists in
+         * Orb, that item will be associated with the line item.
+         */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         /** The number of units on the line item */
         fun quantity(quantity: Double) = apply { body.quantity(quantity) }
 
+        /** The number of units on the line item */
+        fun quantity(quantity: JsonField<Double>) = apply { body.quantity(quantity) }
+
         /** A date string to specify the line item's start date in the customer's timezone. */
         fun startDate(startDate: LocalDate) = apply { body.startDate(startDate) }
 
+        /** A date string to specify the line item's start date in the customer's timezone. */
+        fun startDate(startDate: JsonField<LocalDate>) = apply { body.startDate(startDate) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -333,25 +470,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): InvoiceLineItemCreateParams =
             InvoiceLineItemCreateParams(
                 body.build(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateResponse.kt
index be7809ee..de0059e2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceLineItemCreateResponse.kt
@@ -360,33 +360,37 @@ private constructor(
     fun taxAmounts(): List<TaxAmount> = taxAmounts.getRequired("tax_amounts")
 
     /** A unique ID for this line item. */
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The final amount after any discounts or minimums. */
-    @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+    @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-    @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+    @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
     /** The end date of the range of time applied for this line item's price. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     /**
      * [DEPRECATED] For configured prices that are split by a grouping key, this will be populated
      * with the key and a value. The `amount` and `subtotal` will be the values for this particular
      * grouping.
      */
-    @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+    @JsonProperty("grouping") @ExcludeMissing fun _grouping(): JsonField<String> = grouping
 
-    @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+    @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-    @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+    @JsonProperty("maximum_amount")
+    @ExcludeMissing
+    fun _maximumAmount(): JsonField<String> = maximumAmount
 
-    @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+    @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-    @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+    @JsonProperty("minimum_amount")
+    @ExcludeMissing
+    fun _minimumAmount(): JsonField<String> = minimumAmount
 
     /** The name of the price associated with this line item. */
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
     /**
      * The Price resource represents a price that can be billed on a subscription, resulting in a
@@ -616,26 +620,32 @@ private constructor(
      * }
      * ```
      */
-    @JsonProperty("price") @ExcludeMissing fun _price() = price
+    @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
-    @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+    @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
     /** The start date of the range of time applied for this line item's price. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
     /**
      * For complex pricing structures, the line item can be broken down further in `sub_line_items`.
      */
-    @JsonProperty("sub_line_items") @ExcludeMissing fun _subLineItems() = subLineItems
+    @JsonProperty("sub_line_items")
+    @ExcludeMissing
+    fun _subLineItems(): JsonField<List<SubLineItem>> = subLineItems
 
     /** The line amount before any line item-specific discounts or minimums. */
-    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+    @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
     /**
      * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
      * configured.
      */
-    @JsonProperty("tax_amounts") @ExcludeMissing fun _taxAmounts() = taxAmounts
+    @JsonProperty("tax_amounts")
+    @ExcludeMissing
+    fun _taxAmounts(): JsonField<List<TaxAmount>> = taxAmounts
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -674,22 +684,22 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var amount: JsonField<String> = JsonMissing.of()
-        private var discount: JsonField<Discount> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var grouping: JsonField<String> = JsonMissing.of()
-        private var maximum: JsonField<Maximum> = JsonMissing.of()
-        private var maximumAmount: JsonField<String> = JsonMissing.of()
-        private var minimum: JsonField<Minimum> = JsonMissing.of()
-        private var minimumAmount: JsonField<String> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
-        private var price: JsonField<Price> = JsonMissing.of()
-        private var quantity: JsonField<Double> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var subLineItems: JsonField<List<SubLineItem>> = JsonMissing.of()
-        private var subtotal: JsonField<String> = JsonMissing.of()
-        private var taxAmounts: JsonField<List<TaxAmount>> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var amount: JsonField<String>? = null
+        private var discount: JsonField<Discount>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var grouping: JsonField<String>? = null
+        private var maximum: JsonField<Maximum>? = null
+        private var maximumAmount: JsonField<String>? = null
+        private var minimum: JsonField<Minimum>? = null
+        private var minimumAmount: JsonField<String>? = null
+        private var name: JsonField<String>? = null
+        private var price: JsonField<Price>? = null
+        private var quantity: JsonField<Double>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var subLineItems: JsonField<MutableList<SubLineItem>>? = null
+        private var subtotal: JsonField<String>? = null
+        private var taxAmounts: JsonField<MutableList<TaxAmount>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -707,9 +717,9 @@ private constructor(
             price = invoiceLineItemCreateResponse.price
             quantity = invoiceLineItemCreateResponse.quantity
             startDate = invoiceLineItemCreateResponse.startDate
-            subLineItems = invoiceLineItemCreateResponse.subLineItems
+            subLineItems = invoiceLineItemCreateResponse.subLineItems.map { it.toMutableList() }
             subtotal = invoiceLineItemCreateResponse.subtotal
-            taxAmounts = invoiceLineItemCreateResponse.taxAmounts
+            taxAmounts = invoiceLineItemCreateResponse.taxAmounts.map { it.toMutableList() }
             additionalProperties = invoiceLineItemCreateResponse.additionalProperties.toMutableMap()
         }
 
@@ -725,10 +735,24 @@ private constructor(
         /** The final amount after any discounts or minimums. */
         fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-        fun discount(discount: Discount) = discount(JsonField.of(discount))
+        fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+        fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
         fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+        fun discount(percentageDiscount: PercentageDiscount) =
+            discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+        fun discount(trialDiscount: TrialDiscount) =
+            discount(Discount.ofTrialDiscount(trialDiscount))
+
+        fun discount(usageDiscount: Discount.UsageDiscount) =
+            discount(Discount.ofUsageDiscount(usageDiscount))
+
+        fun discount(amountDiscount: AmountDiscount) =
+            discount(Discount.ofAmountDiscount(amountDiscount))
+
         /** The end date of the range of time applied for this line item's price. */
         fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
 
@@ -740,7 +764,14 @@ private constructor(
          * populated with the key and a value. The `amount` and `subtotal` will be the values for
          * this particular grouping.
          */
-        fun grouping(grouping: String) = grouping(JsonField.of(grouping))
+        fun grouping(grouping: String?) = grouping(JsonField.ofNullable(grouping))
+
+        /**
+         * [DEPRECATED] For configured prices that are split by a grouping key, this will be
+         * populated with the key and a value. The `amount` and `subtotal` will be the values for
+         * this particular grouping.
+         */
+        fun grouping(grouping: Optional<String>) = grouping(grouping.orElse(null))
 
         /**
          * [DEPRECATED] For configured prices that are split by a grouping key, this will be
@@ -749,21 +780,33 @@ private constructor(
          */
         fun grouping(grouping: JsonField<String>) = apply { this.grouping = grouping }
 
-        fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+        fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+        fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
         fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-        fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+        fun maximumAmount(maximumAmount: String?) =
+            maximumAmount(JsonField.ofNullable(maximumAmount))
+
+        fun maximumAmount(maximumAmount: Optional<String>) =
+            maximumAmount(maximumAmount.orElse(null))
 
         fun maximumAmount(maximumAmount: JsonField<String>) = apply {
             this.maximumAmount = maximumAmount
         }
 
-        fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+        fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+        fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
         fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-        fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+        fun minimumAmount(minimumAmount: String?) =
+            minimumAmount(JsonField.ofNullable(minimumAmount))
+
+        fun minimumAmount(minimumAmount: Optional<String>) =
+            minimumAmount(minimumAmount.orElse(null))
 
         fun minimumAmount(minimumAmount: JsonField<String>) = apply {
             this.minimumAmount = minimumAmount
@@ -1003,7 +1046,237 @@ private constructor(
          * }
          * ```
          */
-        fun price(price: Price) = price(JsonField.of(price))
+        fun price(price: Price?) = price(JsonField.ofNullable(price))
+
+        /**
+         * The Price resource represents a price that can be billed on a subscription, resulting in
+         * a charge on an invoice in the form of an invoice line item. Prices take a quantity and
+         * determine an amount to bill.
+         *
+         * Orb supports a few different pricing models out of the box. Each of these models is
+         * serialized differently in a given Price object. The model_type field determines the key
+         * for the configuration object that is present.
+         *
+         * ## Unit pricing
+         *
+         * With unit pricing, each unit costs a fixed amount.
+         *
+         * ```json
+         * {
+         *     ...
+         *     "model_type": "unit",
+         *     "unit_config": {
+         *         "unit_amount": "0.50"
+         *     }
+         *     ...
+         * }
+         * ```
+         *
+         * ## Tiered pricing
+         *
+         * In tiered pricing, the cost of a given unit depends on the tier range that it falls into,
+         * where each tier range is defined by an upper and lower bound. For example, the first ten
+         * units may cost $0.50 each and all units thereafter may cost $0.10 each.
+         *
+         * ```json
+         * {
+         *     ...
+         *     "model_type": "tiered",
+         *     "tiered_config": {
+         *         "tiers": [
+         *             {
+         *                 "first_unit": 1,
+         *                 "last_unit": 10,
+         *                 "unit_amount": "0.50"
+         *             },
+         *             {
+         *                 "first_unit": 11,
+         *                 "last_unit": null,
+         *                 "unit_amount": "0.10"
+         *             }
+         *         ]
+         *     }
+         *     ...
+         * ```
+         *
+         * ## Bulk pricing
+         *
+         * Bulk pricing applies when the number of units determine the cost of all units. For
+         * example, if you've bought less than 10 units, they may each be $0.50 for a total of
+         * $5.00. Once you've bought more than 10 units, all units may now be priced at $0.40 (i.e.
+         * 101 units total would be $40.40).
+         *
+         * ```json
+         * {
+         *     ...
+         *     "model_type": "bulk",
+         *     "bulk_config": {
+         *         "tiers": [
+         *             {
+         *                 "maximum_units": 10,
+         *                 "unit_amount": "0.50"
+         *             },
+         *             {
+         *                 "maximum_units": 1000,
+         *                 "unit_amount": "0.40"
+         *             }
+         *         ]
+         *     }
+         *     ...
+         * }
+         * ```
+         *
+         * ## Package pricing
+         *
+         * Package pricing defines the size or granularity of a unit for billing purposes. For
+         * example, if the package size is set to 5, then 4 units will be billed as 5 and 6 units
+         * will be billed at 10.
+         *
+         * ```json
+         * {
+         *     ...
+         *     "model_type": "package",
+         *     "package_config": {
+         *         "package_amount": "0.80",
+         *         "package_size": 10
+         *     }
+         *     ...
+         * }
+         * ```
+         *
+         * ## BPS pricing
+         *
+         * BPS pricing specifies a per-event (e.g. per-payment) rate in one hundredth of a percent
+         * (the number of basis points to charge), as well as a cap per event to assess. For
+         * example, this would allow you to assess a fee of 0.25% on every payment you process, with
+         * a maximum charge of $25 per payment.
+         *
+         * ```json
+         * {
+         *     ...
+         *     "model_type": "bps",
+         *     "bps_config": {
+         *        "bps": 125,
+         *        "per_unit_maximum": "11.00"
+         *     }
+         *     ...
+         *  }
+         * ```
+         *
+         * ## Bulk BPS pricing
+         *
+         * Bulk BPS pricing specifies BPS parameters in a tiered manner, dependent on the total
+         * quantity across all events. Similar to bulk pricing, the BPS parameters of a given event
+         * depends on the tier range that the billing period falls into. Each tier range is defined
+         * by an upper bound. For example, after $1.5M of payment volume is reached, each individual
+         * payment may have a lower cap or a smaller take-rate.
+         *
+         * ```json
+         *     ...
+         *     "model_type": "bulk_bps",
+         *     "bulk_bps_config": {
+         *         "tiers": [
+         *            {
+         *                 "maximum_amount": "1000000.00",
+         *                 "bps": 125,
+         *                 "per_unit_maximum": "19.00"
+         *            },
+         *           {
+         *                 "maximum_amount": null,
+         *                 "bps": 115,
+         *                 "per_unit_maximum": "4.00"
+         *             }
+         *         ]
+         *     }
+         *     ...
+         * }
+         * ```
+         *
+         * ## Tiered BPS pricing
+         *
+         * Tiered BPS pricing specifies BPS parameters in a graduated manner, where an event's
+         * applicable parameter is a function of its marginal addition to the period total. Similar
+         * to tiered pricing, the BPS parameters of a given event depends on the tier range that it
+         * falls into, where each tier range is defined by an upper and lower bound. For example,
+         * the first few payments may have a 0.8 BPS take-rate and all payments after a specific
+         * volume may incur a take-rate of 0.5 BPS each.
+         *
+         * ```json
+         *     ...
+         *     "model_type": "tiered_bps",
+         *     "tiered_bps_config": {
+         *         "tiers": [
+         *            {
+         *                 "minimum_amount": "0",
+         *                 "maximum_amount": "1000000.00",
+         *                 "bps": 125,
+         *                 "per_unit_maximum": "19.00"
+         *            },
+         *           {
+         *                 "minimum_amount": "1000000.00",
+         *                 "maximum_amount": null,
+         *                 "bps": 115,
+         *                 "per_unit_maximum": "4.00"
+         *             }
+         *         ]
+         *     }
+         *     ...
+         * }
+         * ```
+         *
+         * ## Matrix pricing
+         *
+         * Matrix pricing defines a set of unit prices in a one or two-dimensional matrix.
+         * `dimensions` defines the two event property values evaluated in this pricing model. In a
+         * one-dimensional matrix, the second value is `null`. Every configuration has a list of
+         * `matrix_values` which give the unit prices for specified property values. In a
+         * one-dimensional matrix, the matrix values will have `dimension_values` where the second
+         * value of the pair is null. If an event does not match any of the dimension values in the
+         * matrix, it will resort to the `default_unit_amount`.
+         *
+         * ```json
+         * {
+         *     "model_type": "matrix"
+         *     "matrix_config": {
+         *         "default_unit_amount": "3.00",
+         *         "dimensions": [
+         *             "cluster_name",
+         *             "region"
+         *         ],
+         *         "matrix_values": [
+         *             {
+         *                 "dimension_values": [
+         *                     "alpha",
+         *                     "west"
+         *                 ],
+         *                 "unit_amount": "2.00"
+         *             },
+         *             ...
+         *         ]
+         *     }
+         * }
+         * ```
+         *
+         * ## Fixed fees
+         *
+         * Fixed fees are prices that are applied independent of usage quantities, and follow unit
+         * pricing. They also have an additional parameter `fixed_price_quantity`. If the Price
+         * represents a fixed cost, this represents the quantity of units applied.
+         *
+         * ```json
+         * {
+         *     ...
+         *     "id": "price_id",
+         *     "model_type": "unit",
+         *     "unit_config": {
+         *        "unit_amount": "2.00"
+         *     },
+         *     "fixed_price_quantity": 3.0
+         *     ...
+         * }
+         * ```
+         */
+        fun price(price: Optional<Price>) = price(price.orElse(null))
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -1235,6 +1508,71 @@ private constructor(
          */
         fun price(price: JsonField<Price>) = apply { this.price = price }
 
+        fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+        fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+        fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+        fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+        fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+            price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+        fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+        fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+        fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+        fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+            price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+        fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+            price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+        fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+            price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+        fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+            price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+        fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+            price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+        fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+            price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+        fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+            price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+        fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+            price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+        fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+            price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+        fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+            price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+        fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+            price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+        fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+            price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+        fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+            price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+        fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+            price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+        fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+            price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+        fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+            price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
         fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
 
         fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -1256,7 +1594,24 @@ private constructor(
          * `sub_line_items`.
          */
         fun subLineItems(subLineItems: JsonField<List<SubLineItem>>) = apply {
-            this.subLineItems = subLineItems
+            this.subLineItems = subLineItems.map { it.toMutableList() }
+        }
+
+        /**
+         * For complex pricing structures, the line item can be broken down further in
+         * `sub_line_items`.
+         */
+        fun addSubLineItem(subLineItem: SubLineItem) = apply {
+            subLineItems =
+                (subLineItems ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(subLineItem)
+                }
         }
 
         /** The line amount before any line item-specific discounts or minimums. */
@@ -1276,7 +1631,24 @@ private constructor(
          * configured.
          */
         fun taxAmounts(taxAmounts: JsonField<List<TaxAmount>>) = apply {
-            this.taxAmounts = taxAmounts
+            this.taxAmounts = taxAmounts.map { it.toMutableList() }
+        }
+
+        /**
+         * An array of tax rates and their incurred tax amounts. Empty if no tax integration is
+         * configured.
+         */
+        fun addTaxAmount(taxAmount: TaxAmount) = apply {
+            taxAmounts =
+                (taxAmounts ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(taxAmount)
+                }
         }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -1300,22 +1672,24 @@ private constructor(
 
         fun build(): InvoiceLineItemCreateResponse =
             InvoiceLineItemCreateResponse(
-                id,
-                amount,
-                discount,
-                endDate,
-                grouping,
-                maximum,
-                maximumAmount,
-                minimum,
-                minimumAmount,
-                name,
-                price,
-                quantity,
-                startDate,
-                subLineItems.map { it.toImmutable() },
-                subtotal,
-                taxAmounts.map { it.toImmutable() },
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(amount) { "`amount` is required but was not set" },
+                checkNotNull(discount) { "`discount` is required but was not set" },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(grouping) { "`grouping` is required but was not set" },
+                checkNotNull(maximum) { "`maximum` is required but was not set" },
+                checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                checkNotNull(minimum) { "`minimum` is required but was not set" },
+                checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                checkNotNull(name) { "`name` is required but was not set" },
+                checkNotNull(price) { "`price` is required but was not set" },
+                checkNotNull(quantity) { "`quantity` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(subLineItems) { "`subLineItems` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                checkNotNull(taxAmounts) { "`taxAmounts` is required but was not set" }
+                    .map { it.toImmutable() },
                 additionalProperties.toImmutable(),
             )
     }
@@ -1350,10 +1724,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Maximum amount applied */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1378,13 +1754,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var maximumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximum: Maximum) = apply {
-                appliesToPriceIds = maximum.appliesToPriceIds
+                appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                 maximumAmount = maximum.maximumAmount
                 additionalProperties = maximum.additionalProperties.toMutableMap()
             }
@@ -1401,7 +1777,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this maximum amount applies to. For plan/plan phase maximums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Maximum amount applied */
@@ -1433,8 +1826,11 @@ private constructor(
 
             fun build(): Maximum =
                 Maximum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    maximumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1487,10 +1883,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Minimum amount applied */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1515,13 +1913,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var minimumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimum: Minimum) = apply {
-                appliesToPriceIds = minimum.appliesToPriceIds
+                appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                 minimumAmount = minimum.minimumAmount
                 additionalProperties = minimum.additionalProperties.toMutableMap()
             }
@@ -1538,7 +1936,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this minimum amount applies to. For plan/plan phase minimums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Minimum amount applied */
@@ -1570,8 +1985,11 @@ private constructor(
 
             fun build(): Minimum =
                 Minimum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    minimumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1788,17 +2206,21 @@ private constructor(
             fun type(): Type = type.getRequired("type")
 
             /** The total amount for this sub line item. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-            @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+            @JsonProperty("grouping")
+            @ExcludeMissing
+            fun _grouping(): JsonField<Grouping> = grouping
 
-            @JsonProperty("matrix_config") @ExcludeMissing fun _matrixConfig() = matrixConfig
+            @JsonProperty("matrix_config")
+            @ExcludeMissing
+            fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-            @JsonProperty("type") @ExcludeMissing fun _type() = type
+            @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1827,12 +2249,12 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var grouping: JsonField<Grouping> = JsonMissing.of()
-                private var matrixConfig: JsonField<MatrixConfig> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Double> = JsonMissing.of()
-                private var type: JsonField<Type> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var grouping: JsonField<Grouping>? = null
+                private var matrixConfig: JsonField<MatrixConfig>? = null
+                private var name: JsonField<String>? = null
+                private var quantity: JsonField<Double>? = null
+                private var type: JsonField<Type>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1852,7 +2274,9 @@ private constructor(
                 /** The total amount for this sub line item. */
                 fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                 fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -1899,12 +2323,12 @@ private constructor(
 
                 fun build(): MatrixSubLineItem =
                     MatrixSubLineItem(
-                        amount,
-                        grouping,
-                        matrixConfig,
-                        name,
-                        quantity,
-                        type,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(grouping) { "`grouping` is required but was not set" },
+                        checkNotNull(matrixConfig) { "`matrixConfig` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
+                        checkNotNull(type) { "`type` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1928,10 +2352,10 @@ private constructor(
                 /** No value indicates the default group */
                 fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                @JsonProperty("key") @ExcludeMissing fun _key() = key
+                @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                 /** No value indicates the default group */
-                @JsonProperty("value") @ExcludeMissing fun _value() = value
+                @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1956,8 +2380,8 @@ private constructor(
 
                 class Builder {
 
-                    private var key: JsonField<String> = JsonMissing.of()
-                    private var value: JsonField<String> = JsonMissing.of()
+                    private var key: JsonField<String>? = null
+                    private var value: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1972,7 +2396,10 @@ private constructor(
                     fun key(key: JsonField<String>) = apply { this.key = key }
 
                     /** No value indicates the default group */
-                    fun value(value: String) = value(JsonField.of(value))
+                    fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                    /** No value indicates the default group */
+                    fun value(value: Optional<String>) = value(value.orElse(null))
 
                     /** No value indicates the default group */
                     fun value(value: JsonField<String>) = apply { this.value = value }
@@ -2001,8 +2428,8 @@ private constructor(
 
                     fun build(): Grouping =
                         Grouping(
-                            key,
-                            value,
+                            checkNotNull(key) { "`key` is required but was not set" },
+                            checkNotNull(value) { "`value` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2043,7 +2470,7 @@ private constructor(
                 /** The ordered dimension values for this line item. */
                 @JsonProperty("dimension_values")
                 @ExcludeMissing
-                fun _dimensionValues() = dimensionValues
+                fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2067,12 +2494,12 @@ private constructor(
 
                 class Builder {
 
-                    private var dimensionValues: JsonField<List<String?>> = JsonMissing.of()
+                    private var dimensionValues: JsonField<MutableList<String?>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixConfig: MatrixConfig) = apply {
-                        dimensionValues = matrixConfig.dimensionValues
+                        dimensionValues = matrixConfig.dimensionValues.map { it.toMutableList() }
                         additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                     }
 
@@ -2082,7 +2509,21 @@ private constructor(
 
                     /** The ordered dimension values for this line item. */
                     fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
-                        this.dimensionValues = dimensionValues
+                        this.dimensionValues = dimensionValues.map { it.toMutableList() }
+                    }
+
+                    /** The ordered dimension values for this line item. */
+                    fun addDimensionValue(dimensionValue: String) = apply {
+                        dimensionValues =
+                            (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimensionValue)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -2109,7 +2550,10 @@ private constructor(
 
                     fun build(): MatrixConfig =
                         MatrixConfig(
-                            dimensionValues.map { it.toImmutable() },
+                            checkNotNull(dimensionValues) {
+                                    "`dimensionValues` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable()
                         )
                 }
@@ -2242,17 +2686,21 @@ private constructor(
             fun type(): Type = type.getRequired("type")
 
             /** The total amount for this sub line item. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-            @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+            @JsonProperty("grouping")
+            @ExcludeMissing
+            fun _grouping(): JsonField<Grouping> = grouping
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-            @JsonProperty("tier_config") @ExcludeMissing fun _tierConfig() = tierConfig
+            @JsonProperty("tier_config")
+            @ExcludeMissing
+            fun _tierConfig(): JsonField<TierConfig> = tierConfig
 
-            @JsonProperty("type") @ExcludeMissing fun _type() = type
+            @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2281,12 +2729,12 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var grouping: JsonField<Grouping> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Double> = JsonMissing.of()
-                private var tierConfig: JsonField<TierConfig> = JsonMissing.of()
-                private var type: JsonField<Type> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var grouping: JsonField<Grouping>? = null
+                private var name: JsonField<String>? = null
+                private var quantity: JsonField<Double>? = null
+                private var tierConfig: JsonField<TierConfig>? = null
+                private var type: JsonField<Type>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2306,7 +2754,9 @@ private constructor(
                 /** The total amount for this sub line item. */
                 fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                 fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -2352,12 +2802,12 @@ private constructor(
 
                 fun build(): TierSubLineItem =
                     TierSubLineItem(
-                        amount,
-                        grouping,
-                        name,
-                        quantity,
-                        tierConfig,
-                        type,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(grouping) { "`grouping` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
+                        checkNotNull(tierConfig) { "`tierConfig` is required but was not set" },
+                        checkNotNull(type) { "`type` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2381,10 +2831,10 @@ private constructor(
                 /** No value indicates the default group */
                 fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                @JsonProperty("key") @ExcludeMissing fun _key() = key
+                @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                 /** No value indicates the default group */
-                @JsonProperty("value") @ExcludeMissing fun _value() = value
+                @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2409,8 +2859,8 @@ private constructor(
 
                 class Builder {
 
-                    private var key: JsonField<String> = JsonMissing.of()
-                    private var value: JsonField<String> = JsonMissing.of()
+                    private var key: JsonField<String>? = null
+                    private var value: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2425,7 +2875,10 @@ private constructor(
                     fun key(key: JsonField<String>) = apply { this.key = key }
 
                     /** No value indicates the default group */
-                    fun value(value: String) = value(JsonField.of(value))
+                    fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                    /** No value indicates the default group */
+                    fun value(value: Optional<String>) = value(value.orElse(null))
 
                     /** No value indicates the default group */
                     fun value(value: JsonField<String>) = apply { this.value = value }
@@ -2454,8 +2907,8 @@ private constructor(
 
                     fun build(): Grouping =
                         Grouping(
-                            key,
-                            value,
+                            checkNotNull(key) { "`key` is required but was not set" },
+                            checkNotNull(value) { "`value` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2502,11 +2955,17 @@ private constructor(
 
                 fun unitAmount(): String = unitAmount.getRequired("unit_amount")
 
-                @JsonProperty("first_unit") @ExcludeMissing fun _firstUnit() = firstUnit
+                @JsonProperty("first_unit")
+                @ExcludeMissing
+                fun _firstUnit(): JsonField<Double> = firstUnit
 
-                @JsonProperty("last_unit") @ExcludeMissing fun _lastUnit() = lastUnit
+                @JsonProperty("last_unit")
+                @ExcludeMissing
+                fun _lastUnit(): JsonField<Double> = lastUnit
 
-                @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2532,9 +2991,9 @@ private constructor(
 
                 class Builder {
 
-                    private var firstUnit: JsonField<Double> = JsonMissing.of()
-                    private var lastUnit: JsonField<Double> = JsonMissing.of()
-                    private var unitAmount: JsonField<String> = JsonMissing.of()
+                    private var firstUnit: JsonField<Double>? = null
+                    private var lastUnit: JsonField<Double>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2551,7 +3010,13 @@ private constructor(
                         this.firstUnit = firstUnit
                     }
 
-                    fun lastUnit(lastUnit: Double) = lastUnit(JsonField.of(lastUnit))
+                    fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
+
+                    fun lastUnit(lastUnit: Double) = lastUnit(lastUnit as Double?)
+
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun lastUnit(lastUnit: Optional<Double>) =
+                        lastUnit(lastUnit.orElse(null) as Double?)
 
                     fun lastUnit(lastUnit: JsonField<Double>) = apply { this.lastUnit = lastUnit }
 
@@ -2585,9 +3050,9 @@ private constructor(
 
                     fun build(): TierConfig =
                         TierConfig(
-                            firstUnit,
-                            lastUnit,
-                            unitAmount,
+                            checkNotNull(firstUnit) { "`firstUnit` is required but was not set" },
+                            checkNotNull(lastUnit) { "`lastUnit` is required but was not set" },
+                            checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2715,15 +3180,17 @@ private constructor(
             fun type(): Type = type.getRequired("type")
 
             /** The total amount for this sub line item. */
-            @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
-            @JsonProperty("grouping") @ExcludeMissing fun _grouping() = grouping
+            @JsonProperty("grouping")
+            @ExcludeMissing
+            fun _grouping(): JsonField<Grouping> = grouping
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-            @JsonProperty("type") @ExcludeMissing fun _type() = type
+            @JsonProperty("type") @ExcludeMissing fun _type(): JsonField<Type> = type
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2751,11 +3218,11 @@ private constructor(
 
             class Builder {
 
-                private var amount: JsonField<String> = JsonMissing.of()
-                private var grouping: JsonField<Grouping> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Double> = JsonMissing.of()
-                private var type: JsonField<Type> = JsonMissing.of()
+                private var amount: JsonField<String>? = null
+                private var grouping: JsonField<Grouping>? = null
+                private var name: JsonField<String>? = null
+                private var quantity: JsonField<Double>? = null
+                private var type: JsonField<Type>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2774,7 +3241,9 @@ private constructor(
                 /** The total amount for this sub line item. */
                 fun amount(amount: JsonField<String>) = apply { this.amount = amount }
 
-                fun grouping(grouping: Grouping) = grouping(JsonField.of(grouping))
+                fun grouping(grouping: Grouping?) = grouping(JsonField.ofNullable(grouping))
+
+                fun grouping(grouping: Optional<Grouping>) = grouping(grouping.orElse(null))
 
                 fun grouping(grouping: JsonField<Grouping>) = apply { this.grouping = grouping }
 
@@ -2814,11 +3283,11 @@ private constructor(
 
                 fun build(): OtherSubLineItem =
                     OtherSubLineItem(
-                        amount,
-                        grouping,
-                        name,
-                        quantity,
-                        type,
+                        checkNotNull(amount) { "`amount` is required but was not set" },
+                        checkNotNull(grouping) { "`grouping` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
+                        checkNotNull(type) { "`type` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2842,10 +3311,10 @@ private constructor(
                 /** No value indicates the default group */
                 fun value(): Optional<String> = Optional.ofNullable(value.getNullable("value"))
 
-                @JsonProperty("key") @ExcludeMissing fun _key() = key
+                @JsonProperty("key") @ExcludeMissing fun _key(): JsonField<String> = key
 
                 /** No value indicates the default group */
-                @JsonProperty("value") @ExcludeMissing fun _value() = value
+                @JsonProperty("value") @ExcludeMissing fun _value(): JsonField<String> = value
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2870,8 +3339,8 @@ private constructor(
 
                 class Builder {
 
-                    private var key: JsonField<String> = JsonMissing.of()
-                    private var value: JsonField<String> = JsonMissing.of()
+                    private var key: JsonField<String>? = null
+                    private var value: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2886,7 +3355,10 @@ private constructor(
                     fun key(key: JsonField<String>) = apply { this.key = key }
 
                     /** No value indicates the default group */
-                    fun value(value: String) = value(JsonField.of(value))
+                    fun value(value: String?) = value(JsonField.ofNullable(value))
+
+                    /** No value indicates the default group */
+                    fun value(value: Optional<String>) = value(value.orElse(null))
 
                     /** No value indicates the default group */
                     fun value(value: JsonField<String>) = apply { this.value = value }
@@ -2915,8 +3387,8 @@ private constructor(
 
                     fun build(): Grouping =
                         Grouping(
-                            key,
-                            value,
+                            checkNotNull(key) { "`key` is required but was not set" },
+                            checkNotNull(value) { "`value` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -3037,17 +3509,17 @@ private constructor(
             Optional.ofNullable(taxRatePercentage.getNullable("tax_rate_percentage"))
 
         /** The amount of additional tax incurred by this tax rate. */
-        @JsonProperty("amount") @ExcludeMissing fun _amount() = amount
+        @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
         /** The human-readable description of the applied tax rate. */
         @JsonProperty("tax_rate_description")
         @ExcludeMissing
-        fun _taxRateDescription() = taxRateDescription
+        fun _taxRateDescription(): JsonField<String> = taxRateDescription
 
         /** The tax rate percentage, out of 100. */
         @JsonProperty("tax_rate_percentage")
         @ExcludeMissing
-        fun _taxRatePercentage() = taxRatePercentage
+        fun _taxRatePercentage(): JsonField<String> = taxRatePercentage
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3073,9 +3545,9 @@ private constructor(
 
         class Builder {
 
-            private var amount: JsonField<String> = JsonMissing.of()
-            private var taxRateDescription: JsonField<String> = JsonMissing.of()
-            private var taxRatePercentage: JsonField<String> = JsonMissing.of()
+            private var amount: JsonField<String>? = null
+            private var taxRateDescription: JsonField<String>? = null
+            private var taxRatePercentage: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3102,8 +3574,12 @@ private constructor(
             }
 
             /** The tax rate percentage, out of 100. */
-            fun taxRatePercentage(taxRatePercentage: String) =
-                taxRatePercentage(JsonField.of(taxRatePercentage))
+            fun taxRatePercentage(taxRatePercentage: String?) =
+                taxRatePercentage(JsonField.ofNullable(taxRatePercentage))
+
+            /** The tax rate percentage, out of 100. */
+            fun taxRatePercentage(taxRatePercentage: Optional<String>) =
+                taxRatePercentage(taxRatePercentage.orElse(null))
 
             /** The tax rate percentage, out of 100. */
             fun taxRatePercentage(taxRatePercentage: JsonField<String>) = apply {
@@ -3131,9 +3607,13 @@ private constructor(
 
             fun build(): TaxAmount =
                 TaxAmount(
-                    amount,
-                    taxRateDescription,
-                    taxRatePercentage,
+                    checkNotNull(amount) { "`amount` is required but was not set" },
+                    checkNotNull(taxRateDescription) {
+                        "`taxRateDescription` is required but was not set"
+                    },
+                    checkNotNull(taxRatePercentage) {
+                        "`taxRatePercentage` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceListParams.kt
index 225b2d57..044128a5 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceListParams.kt
@@ -16,6 +16,20 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all [`Invoice`](../guides/concepts#invoice)s for an account in a
+ * list format.
+ *
+ * The list of invoices is ordered starting from the most recently issued invoice date. The response
+ * also includes [`pagination_metadata`](../reference/pagination), which lets the caller retrieve
+ * the next page of results if they exist.
+ *
+ * By default, this only returns invoices that are `issued`, `paid`, or `synced`.
+ *
+ * When fetching any `draft` invoices, this returns the last-computed invoice values for each draft
+ * invoice, which may not always be up-to-date since Orb regularly refreshes invoices
+ * asynchronously.
+ */
 class InvoiceListParams
 constructor(
     private val amount: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceMarkPaidParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceMarkPaidParams.kt
index 1b693eaa..f599a942 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceMarkPaidParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceMarkPaidParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,10 @@ import java.time.LocalDate
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows an invoice's status to be set the `paid` status. This can only be done to
+ * invoices that are in the `issued` status.
+ */
 class InvoiceMarkPaidParams
 constructor(
     private val invoiceId: String,
@@ -36,12 +42,21 @@ constructor(
     /** An optional note to associate with the payment. */
     fun notes(): Optional<String> = body.notes()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** A date string to specify the date of the payment. */
+    fun _paymentReceivedDate(): JsonField<LocalDate> = body._paymentReceivedDate()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** An optional external ID to associate with the payment. */
+    fun _externalId(): JsonField<String> = body._externalId()
+
+    /** An optional note to associate with the payment. */
+    fun _notes(): JsonField<String> = body._notes()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): InvoiceMarkPaidBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -59,28 +74,58 @@ constructor(
     class InvoiceMarkPaidBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("payment_received_date") private val paymentReceivedDate: LocalDate,
-        @JsonProperty("external_id") private val externalId: String?,
-        @JsonProperty("notes") private val notes: String?,
+        @JsonProperty("payment_received_date")
+        @ExcludeMissing
+        private val paymentReceivedDate: JsonField<LocalDate> = JsonMissing.of(),
+        @JsonProperty("external_id")
+        @ExcludeMissing
+        private val externalId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("notes")
+        @ExcludeMissing
+        private val notes: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /** A date string to specify the date of the payment. */
+        fun paymentReceivedDate(): LocalDate =
+            paymentReceivedDate.getRequired("payment_received_date")
+
+        /** An optional external ID to associate with the payment. */
+        fun externalId(): Optional<String> =
+            Optional.ofNullable(externalId.getNullable("external_id"))
+
+        /** An optional note to associate with the payment. */
+        fun notes(): Optional<String> = Optional.ofNullable(notes.getNullable("notes"))
+
         /** A date string to specify the date of the payment. */
         @JsonProperty("payment_received_date")
-        fun paymentReceivedDate(): LocalDate = paymentReceivedDate
+        @ExcludeMissing
+        fun _paymentReceivedDate(): JsonField<LocalDate> = paymentReceivedDate
 
         /** An optional external ID to associate with the payment. */
         @JsonProperty("external_id")
-        fun externalId(): Optional<String> = Optional.ofNullable(externalId)
+        @ExcludeMissing
+        fun _externalId(): JsonField<String> = externalId
 
         /** An optional note to associate with the payment. */
-        @JsonProperty("notes") fun notes(): Optional<String> = Optional.ofNullable(notes)
+        @JsonProperty("notes") @ExcludeMissing fun _notes(): JsonField<String> = notes
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceMarkPaidBody = apply {
+            if (!validated) {
+                paymentReceivedDate()
+                externalId()
+                notes()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -90,9 +135,9 @@ constructor(
 
         class Builder {
 
-            private var paymentReceivedDate: LocalDate? = null
-            private var externalId: String? = null
-            private var notes: String? = null
+            private var paymentReceivedDate: JsonField<LocalDate>? = null
+            private var externalId: JsonField<String> = JsonMissing.of()
+            private var notes: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -104,22 +149,32 @@ constructor(
             }
 
             /** A date string to specify the date of the payment. */
-            fun paymentReceivedDate(paymentReceivedDate: LocalDate) = apply {
+            fun paymentReceivedDate(paymentReceivedDate: LocalDate) =
+                paymentReceivedDate(JsonField.of(paymentReceivedDate))
+
+            /** A date string to specify the date of the payment. */
+            fun paymentReceivedDate(paymentReceivedDate: JsonField<LocalDate>) = apply {
                 this.paymentReceivedDate = paymentReceivedDate
             }
 
             /** An optional external ID to associate with the payment. */
-            fun externalId(externalId: String?) = apply { this.externalId = externalId }
+            fun externalId(externalId: String?) = externalId(JsonField.ofNullable(externalId))
 
             /** An optional external ID to associate with the payment. */
             fun externalId(externalId: Optional<String>) = externalId(externalId.orElse(null))
 
+            /** An optional external ID to associate with the payment. */
+            fun externalId(externalId: JsonField<String>) = apply { this.externalId = externalId }
+
             /** An optional note to associate with the payment. */
-            fun notes(notes: String?) = apply { this.notes = notes }
+            fun notes(notes: String?) = notes(JsonField.ofNullable(notes))
 
             /** An optional note to associate with the payment. */
             fun notes(notes: Optional<String>) = notes(notes.orElse(null))
 
+            /** An optional note to associate with the payment. */
+            fun notes(notes: JsonField<String>) = apply { this.notes = notes }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -198,18 +253,48 @@ constructor(
             body.paymentReceivedDate(paymentReceivedDate)
         }
 
+        /** A date string to specify the date of the payment. */
+        fun paymentReceivedDate(paymentReceivedDate: JsonField<LocalDate>) = apply {
+            body.paymentReceivedDate(paymentReceivedDate)
+        }
+
         /** An optional external ID to associate with the payment. */
         fun externalId(externalId: String?) = apply { body.externalId(externalId) }
 
         /** An optional external ID to associate with the payment. */
         fun externalId(externalId: Optional<String>) = externalId(externalId.orElse(null))
 
+        /** An optional external ID to associate with the payment. */
+        fun externalId(externalId: JsonField<String>) = apply { body.externalId(externalId) }
+
         /** An optional note to associate with the payment. */
         fun notes(notes: String?) = apply { body.notes(notes) }
 
         /** An optional note to associate with the payment. */
         fun notes(notes: Optional<String>) = notes(notes.orElse(null))
 
+        /** An optional note to associate with the payment. */
+        fun notes(notes: JsonField<String>) = apply { body.notes(notes) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -308,25 +393,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): InvoiceMarkPaidParams =
             InvoiceMarkPaidParams(
                 checkNotNull(invoiceId) { "`invoiceId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoicePayParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoicePayParams.kt
index d1d9abfd..e5c18a0d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoicePayParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoicePayParams.kt
@@ -10,6 +10,10 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint collects payment for an invoice using the customer's default payment method. This
+ * action can only be taken on invoices with status "issued".
+ */
 class InvoicePayParams
 constructor(
     private val invoiceId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceUpdateParams.kt
index a927fda1..356da205 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,12 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to update the `metadata` property on an invoice. If you pass null for
+ * the metadata value, it will clear any existing metadata for that invoice.
+ *
+ * `metadata` can be modified regardless of invoice state.
+ */
 class InvoiceUpdateParams
 constructor(
     private val invoiceId: String,
@@ -33,12 +41,19 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): InvoiceUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -56,7 +71,9 @@ constructor(
     class InvoiceUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -66,12 +83,28 @@ constructor(
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): InvoiceUpdateBody = apply {
+            if (!validated) {
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -81,7 +114,7 @@ constructor(
 
         class Builder {
 
-            private var metadata: Metadata? = null
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -95,7 +128,7 @@ constructor(
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -104,6 +137,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -184,6 +224,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -282,25 +348,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): InvoiceUpdateParams =
             InvoiceUpdateParams(
                 checkNotNull(invoiceId) { "`invoiceId` is required but was not set" },
@@ -327,6 +374,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceVoidInvoiceParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceVoidInvoiceParams.kt
index 3c471265..646277d2 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceVoidInvoiceParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/InvoiceVoidInvoiceParams.kt
@@ -10,6 +10,14 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows an invoice's status to be set the `void` status. This can only be done to
+ * invoices that are in the `issued` status.
+ *
+ * If the associated invoice has used the customer balance to change the amount due, the customer
+ * balance operation will be reverted. For example, if the invoice used $10 of customer balance,
+ * that amount will be added back to the customer balance upon voiding.
+ */
 class InvoiceVoidInvoiceParams
 constructor(
     private val invoiceId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Item.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Item.kt
index 48281b09..8a6b40a0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Item.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Item.kt
@@ -47,15 +47,17 @@ private constructor(
 
     fun name(): String = name.getRequired("name")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     @JsonProperty("external_connections")
     @ExcludeMissing
-    fun _externalConnections() = externalConnections
+    fun _externalConnections(): JsonField<List<ExternalConnection>> = externalConnections
 
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -82,17 +84,17 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var externalConnections: JsonField<List<ExternalConnection>> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var externalConnections: JsonField<MutableList<ExternalConnection>>? = null
+        private var name: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(item: Item) = apply {
             id = item.id
             createdAt = item.createdAt
-            externalConnections = item.externalConnections
+            externalConnections = item.externalConnections.map { it.toMutableList() }
             name = item.name
             additionalProperties = item.additionalProperties.toMutableMap()
         }
@@ -109,7 +111,20 @@ private constructor(
             externalConnections(JsonField.of(externalConnections))
 
         fun externalConnections(externalConnections: JsonField<List<ExternalConnection>>) = apply {
-            this.externalConnections = externalConnections
+            this.externalConnections = externalConnections.map { it.toMutableList() }
+        }
+
+        fun addExternalConnection(externalConnection: ExternalConnection) = apply {
+            externalConnections =
+                (externalConnections ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(externalConnection)
+                }
         }
 
         fun name(name: String) = name(JsonField.of(name))
@@ -137,10 +152,13 @@ private constructor(
 
         fun build(): Item =
             Item(
-                id,
-                createdAt,
-                externalConnections.map { it.toImmutable() },
-                name,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(externalConnections) {
+                        "`externalConnections` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(name) { "`name` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -166,11 +184,11 @@ private constructor(
 
         @JsonProperty("external_connection_name")
         @ExcludeMissing
-        fun _externalConnectionName() = externalConnectionName
+        fun _externalConnectionName(): JsonField<ExternalConnectionName> = externalConnectionName
 
         @JsonProperty("external_entity_id")
         @ExcludeMissing
-        fun _externalEntityId() = externalEntityId
+        fun _externalEntityId(): JsonField<String> = externalEntityId
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -195,8 +213,8 @@ private constructor(
 
         class Builder {
 
-            private var externalConnectionName: JsonField<ExternalConnectionName> = JsonMissing.of()
-            private var externalEntityId: JsonField<String> = JsonMissing.of()
+            private var externalConnectionName: JsonField<ExternalConnectionName>? = null
+            private var externalEntityId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -242,8 +260,12 @@ private constructor(
 
             fun build(): ExternalConnection =
                 ExternalConnection(
-                    externalConnectionName,
-                    externalEntityId,
+                    checkNotNull(externalConnectionName) {
+                        "`externalConnectionName` is required but was not set"
+                    },
+                    checkNotNull(externalEntityId) {
+                        "`externalEntityId` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemCreateParams.kt
index 5d6d559d..5fe6f360 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemCreateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -15,6 +17,7 @@ import com.withorb.api.core.immutableEmptyMap
 import com.withorb.api.core.toImmutable
 import java.util.Objects
 
+/** This endpoint is used to create an [Item](../guides/concepts#item). */
 class ItemCreateParams
 constructor(
     private val body: ItemCreateBody,
@@ -25,12 +28,15 @@ constructor(
     /** The name of the item. */
     fun name(): String = body.name()
 
+    /** The name of the item. */
+    fun _name(): JsonField<String> = body._name()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): ItemCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -41,18 +47,32 @@ constructor(
     class ItemCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The name of the item. */
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
+
+        /** The name of the item. */
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ItemCreateBody = apply {
+            if (!validated) {
+                name()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -62,7 +82,7 @@ constructor(
 
         class Builder {
 
-            private var name: String? = null
+            private var name: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -72,7 +92,10 @@ constructor(
             }
 
             /** The name of the item. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the item. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -142,6 +165,28 @@ constructor(
         /** The name of the item. */
         fun name(name: String) = apply { body.name(name) }
 
+        /** The name of the item. */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -240,25 +285,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): ItemCreateParams =
             ItemCreateParams(
                 body.build(),
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemFetchParams.kt
index 0770e879..98d1024d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemFetchParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** This endpoint returns an item identified by its item_id. */
 class ItemFetchParams
 constructor(
     private val itemId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemListParams.kt
index a465ffc9..f6b58d0a 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemListParams.kt
@@ -8,6 +8,7 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/** This endpoint returns a list of all Items, ordered in descending order by creation time. */
 class ItemListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemUpdateParams.kt
index d6ed6032..08d5a616 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/ItemUpdateParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -19,6 +20,7 @@ import com.withorb.api.errors.OrbInvalidDataException
 import java.util.Objects
 import java.util.Optional
 
+/** This endpoint can be used to update properties on the Item. */
 class ItemUpdateParams
 constructor(
     private val itemId: String,
@@ -33,12 +35,16 @@ constructor(
 
     fun name(): Optional<String> = body.name()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _externalConnections(): JsonField<List<ExternalConnection>> = body._externalConnections()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    fun _name(): JsonField<String> = body._name()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): ItemUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -62,22 +68,40 @@ constructor(
     @JsonCreator
     internal constructor(
         @JsonProperty("external_connections")
-        private val externalConnections: List<ExternalConnection>?,
-        @JsonProperty("name") private val name: String?,
+        @ExcludeMissing
+        private val externalConnections: JsonField<List<ExternalConnection>> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("external_connections")
         fun externalConnections(): Optional<List<ExternalConnection>> =
-            Optional.ofNullable(externalConnections)
+            Optional.ofNullable(externalConnections.getNullable("external_connections"))
+
+        fun name(): Optional<String> = Optional.ofNullable(name.getNullable("name"))
 
-        @JsonProperty("name") fun name(): Optional<String> = Optional.ofNullable(name)
+        @JsonProperty("external_connections")
+        @ExcludeMissing
+        fun _externalConnections(): JsonField<List<ExternalConnection>> = externalConnections
+
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ItemUpdateBody = apply {
+            if (!validated) {
+                externalConnections().map { it.forEach { it.validate() } }
+                name()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -87,33 +111,47 @@ constructor(
 
         class Builder {
 
-            private var externalConnections: MutableList<ExternalConnection>? = null
-            private var name: String? = null
+            private var externalConnections: JsonField<MutableList<ExternalConnection>>? = null
+            private var name: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(itemUpdateBody: ItemUpdateBody) = apply {
-                externalConnections = itemUpdateBody.externalConnections?.toMutableList()
+                externalConnections = itemUpdateBody.externalConnections.map { it.toMutableList() }
                 name = itemUpdateBody.name
                 additionalProperties = itemUpdateBody.additionalProperties.toMutableMap()
             }
 
-            fun externalConnections(externalConnections: List<ExternalConnection>?) = apply {
-                this.externalConnections = externalConnections?.toMutableList()
-            }
+            fun externalConnections(externalConnections: List<ExternalConnection>?) =
+                externalConnections(JsonField.ofNullable(externalConnections))
 
             fun externalConnections(externalConnections: Optional<List<ExternalConnection>>) =
                 externalConnections(externalConnections.orElse(null))
 
+            fun externalConnections(externalConnections: JsonField<List<ExternalConnection>>) =
+                apply {
+                    this.externalConnections = externalConnections.map { it.toMutableList() }
+                }
+
             fun addExternalConnection(externalConnection: ExternalConnection) = apply {
                 externalConnections =
-                    (externalConnections ?: mutableListOf()).apply { add(externalConnection) }
+                    (externalConnections ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(externalConnection)
+                    }
             }
 
-            fun name(name: String?) = apply { this.name = name }
+            fun name(name: String?) = name(JsonField.ofNullable(name))
 
             fun name(name: Optional<String>) = name(name.orElse(null))
 
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -135,7 +173,7 @@ constructor(
 
             fun build(): ItemUpdateBody =
                 ItemUpdateBody(
-                    externalConnections?.toImmutable(),
+                    (externalConnections ?: JsonMissing.of()).map { it.toImmutable() },
                     name,
                     additionalProperties.toImmutable(),
                 )
@@ -191,6 +229,10 @@ constructor(
         fun externalConnections(externalConnections: Optional<List<ExternalConnection>>) =
             externalConnections(externalConnections.orElse(null))
 
+        fun externalConnections(externalConnections: JsonField<List<ExternalConnection>>) = apply {
+            body.externalConnections(externalConnections)
+        }
+
         fun addExternalConnection(externalConnection: ExternalConnection) = apply {
             body.addExternalConnection(externalConnection)
         }
@@ -199,6 +241,27 @@ constructor(
 
         fun name(name: Optional<String>) = name(name.orElse(null))
 
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -297,25 +360,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): ItemUpdateParams =
             ItemUpdateParams(
                 checkNotNull(itemId) { "`itemId` is required but was not set" },
@@ -330,21 +374,42 @@ constructor(
     @JsonCreator
     private constructor(
         @JsonProperty("external_connection_name")
-        private val externalConnectionName: ExternalConnectionName,
-        @JsonProperty("external_entity_id") private val externalEntityId: String,
+        @ExcludeMissing
+        private val externalConnectionName: JsonField<ExternalConnectionName> = JsonMissing.of(),
+        @JsonProperty("external_entity_id")
+        @ExcludeMissing
+        private val externalEntityId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        fun externalConnectionName(): ExternalConnectionName =
+            externalConnectionName.getRequired("external_connection_name")
+
+        fun externalEntityId(): String = externalEntityId.getRequired("external_entity_id")
+
         @JsonProperty("external_connection_name")
-        fun externalConnectionName(): ExternalConnectionName = externalConnectionName
+        @ExcludeMissing
+        fun _externalConnectionName(): JsonField<ExternalConnectionName> = externalConnectionName
 
-        @JsonProperty("external_entity_id") fun externalEntityId(): String = externalEntityId
+        @JsonProperty("external_entity_id")
+        @ExcludeMissing
+        fun _externalEntityId(): JsonField<String> = externalEntityId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ExternalConnection = apply {
+            if (!validated) {
+                externalConnectionName()
+                externalEntityId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -354,8 +419,8 @@ constructor(
 
         class Builder {
 
-            private var externalConnectionName: ExternalConnectionName? = null
-            private var externalEntityId: String? = null
+            private var externalConnectionName: JsonField<ExternalConnectionName>? = null
+            private var externalEntityId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -365,11 +430,18 @@ constructor(
                 additionalProperties = externalConnection.additionalProperties.toMutableMap()
             }
 
-            fun externalConnectionName(externalConnectionName: ExternalConnectionName) = apply {
-                this.externalConnectionName = externalConnectionName
-            }
+            fun externalConnectionName(externalConnectionName: ExternalConnectionName) =
+                externalConnectionName(JsonField.of(externalConnectionName))
+
+            fun externalConnectionName(externalConnectionName: JsonField<ExternalConnectionName>) =
+                apply {
+                    this.externalConnectionName = externalConnectionName
+                }
+
+            fun externalEntityId(externalEntityId: String) =
+                externalEntityId(JsonField.of(externalEntityId))
 
-            fun externalEntityId(externalEntityId: String) = apply {
+            fun externalEntityId(externalEntityId: JsonField<String>) = apply {
                 this.externalEntityId = externalEntityId
             }
 
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricCreateParams.kt
index 967cbe45..37864119 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricCreateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to create a [metric](../guides/concepts##metric) using a SQL string. See
+ * [SQL support](../guides/extensibility/advanced-metrics#sql-support) for a description of
+ * constructing SQL queries with examples.
+ */
 class MetricCreateParams
 constructor(
     private val body: MetricCreateBody,
@@ -42,12 +49,31 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** A description of the metric. */
+    fun _description(): JsonField<String> = body._description()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The id of the item */
+    fun _itemId(): JsonField<String> = body._itemId()
+
+    /** The name of the metric. */
+    fun _name(): JsonField<String> = body._name()
+
+    /** A sql string defining the metric. */
+    fun _sql(): JsonField<String> = body._sql()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): MetricCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -58,39 +84,81 @@ constructor(
     class MetricCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("description") private val description: String?,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("sql") private val sql: String,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("description")
+        @ExcludeMissing
+        private val description: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("sql") @ExcludeMissing private val sql: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /** A description of the metric. */
+        fun description(): Optional<String> =
+            Optional.ofNullable(description.getNullable("description"))
+
+        /** The id of the item */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        /** The name of the metric. */
+        fun name(): String = name.getRequired("name")
+
+        /** A sql string defining the metric. */
+        fun sql(): String = sql.getRequired("sql")
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
         /** A description of the metric. */
         @JsonProperty("description")
-        fun description(): Optional<String> = Optional.ofNullable(description)
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
         /** The id of the item */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
         /** The name of the metric. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** A sql string defining the metric. */
-        @JsonProperty("sql") fun sql(): String = sql
+        @JsonProperty("sql") @ExcludeMissing fun _sql(): JsonField<String> = sql
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): MetricCreateBody = apply {
+            if (!validated) {
+                description()
+                itemId()
+                name()
+                sql()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -100,11 +168,11 @@ constructor(
 
         class Builder {
 
-            private var description: String? = null
-            private var itemId: String? = null
-            private var name: String? = null
-            private var sql: String? = null
-            private var metadata: Metadata? = null
+            private var description: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var sql: JsonField<String>? = null
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -118,26 +186,40 @@ constructor(
             }
 
             /** A description of the metric. */
-            fun description(description: String?) = apply { this.description = description }
+            fun description(description: String?) = description(JsonField.ofNullable(description))
 
             /** A description of the metric. */
             fun description(description: Optional<String>) = description(description.orElse(null))
 
+            /** A description of the metric. */
+            fun description(description: JsonField<String>) = apply {
+                this.description = description
+            }
+
+            /** The id of the item */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
             /** The id of the item */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
             /** The name of the metric. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the metric. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            /** A sql string defining the metric. */
+            fun sql(sql: String) = sql(JsonField.of(sql))
 
             /** A sql string defining the metric. */
-            fun sql(sql: String) = apply { this.sql = sql }
+            fun sql(sql: JsonField<String>) = apply { this.sql = sql }
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -146,6 +228,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -167,7 +256,7 @@ constructor(
 
             fun build(): MetricCreateBody =
                 MetricCreateBody(
-                    description,
+                    checkNotNull(description) { "`description` is required but was not set" },
                     checkNotNull(itemId) { "`itemId` is required but was not set" },
                     checkNotNull(name) { "`name` is required but was not set" },
                     checkNotNull(sql) { "`sql` is required but was not set" },
@@ -221,15 +310,27 @@ constructor(
         /** A description of the metric. */
         fun description(description: Optional<String>) = description(description.orElse(null))
 
+        /** A description of the metric. */
+        fun description(description: JsonField<String>) = apply { body.description(description) }
+
         /** The id of the item */
         fun itemId(itemId: String) = apply { body.itemId(itemId) }
 
+        /** The id of the item */
+        fun itemId(itemId: JsonField<String>) = apply { body.itemId(itemId) }
+
         /** The name of the metric. */
         fun name(name: String) = apply { body.name(name) }
 
+        /** The name of the metric. */
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         /** A sql string defining the metric. */
         fun sql(sql: String) = apply { body.sql(sql) }
 
+        /** A sql string defining the metric. */
+        fun sql(sql: JsonField<String>) = apply { body.sql(sql) }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -244,6 +345,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -342,25 +469,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): MetricCreateParams =
             MetricCreateParams(
                 body.build(),
@@ -386,6 +494,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricFetchParams.kt
index 33bdf9c9..d1ddb626 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricFetchParams.kt
@@ -7,6 +7,10 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to list [metrics](../guides/concepts##metric). It returns information about
+ * the metrics including its name, description, and item.
+ */
 class MetricFetchParams
 constructor(
     private val metricId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricListParams.kt
index d2e12d65..b052c588 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricListParams.kt
@@ -10,6 +10,10 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to fetch [metric](../guides/concepts#metric) details given a metric
+ * identifier. It returns information about the metrics including its name, description, and item.
+ */
 class MetricListParams
 constructor(
     private val createdAtGt: OffsetDateTime?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricUpdateParams.kt
index 2cd90ec6..b9b04850 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/MetricUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,10 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to update the `metadata` property on a metric. If you pass `null` for
+ * the metadata value, it will clear any existing metadata for that invoice.
+ */
 class MetricUpdateParams
 constructor(
     private val metricId: String,
@@ -33,12 +39,19 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): MetricUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -56,7 +69,9 @@ constructor(
     class MetricUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -66,12 +81,28 @@ constructor(
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): MetricUpdateBody = apply {
+            if (!validated) {
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -81,7 +112,7 @@ constructor(
 
         class Builder {
 
-            private var metadata: Metadata? = null
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -95,7 +126,7 @@ constructor(
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -104,6 +135,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -184,6 +222,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -282,25 +346,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): MetricUpdateParams =
             MetricUpdateParams(
                 checkNotNull(metricId) { "`metricId` is required but was not set" },
@@ -327,6 +372,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PaginationMetadata.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PaginationMetadata.kt
index 4464fb6d..1d1de4ab 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PaginationMetadata.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PaginationMetadata.kt
@@ -33,9 +33,9 @@ private constructor(
 
     fun nextCursor(): Optional<String> = Optional.ofNullable(nextCursor.getNullable("next_cursor"))
 
-    @JsonProperty("has_more") @ExcludeMissing fun _hasMore() = hasMore
+    @JsonProperty("has_more") @ExcludeMissing fun _hasMore(): JsonField<Boolean> = hasMore
 
-    @JsonProperty("next_cursor") @ExcludeMissing fun _nextCursor() = nextCursor
+    @JsonProperty("next_cursor") @ExcludeMissing fun _nextCursor(): JsonField<String> = nextCursor
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -60,8 +60,8 @@ private constructor(
 
     class Builder {
 
-        private var hasMore: JsonField<Boolean> = JsonMissing.of()
-        private var nextCursor: JsonField<String> = JsonMissing.of()
+        private var hasMore: JsonField<Boolean>? = null
+        private var nextCursor: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -75,7 +75,9 @@ private constructor(
 
         fun hasMore(hasMore: JsonField<Boolean>) = apply { this.hasMore = hasMore }
 
-        fun nextCursor(nextCursor: String) = nextCursor(JsonField.of(nextCursor))
+        fun nextCursor(nextCursor: String?) = nextCursor(JsonField.ofNullable(nextCursor))
+
+        fun nextCursor(nextCursor: Optional<String>) = nextCursor(nextCursor.orElse(null))
 
         fun nextCursor(nextCursor: JsonField<String>) = apply { this.nextCursor = nextCursor }
 
@@ -100,8 +102,8 @@ private constructor(
 
         fun build(): PaginationMetadata =
             PaginationMetadata(
-                hasMore,
-                nextCursor,
+                checkNotNull(hasMore) { "`hasMore` is required but was not set" },
+                checkNotNull(nextCursor) { "`nextCursor` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PercentageDiscount.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PercentageDiscount.kt
index 42970b62..c5448677 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PercentageDiscount.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PercentageDiscount.kt
@@ -56,16 +56,18 @@ private constructor(
      */
     @JsonProperty("applies_to_price_ids")
     @ExcludeMissing
-    fun _appliesToPriceIds() = appliesToPriceIds
+    fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-    @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+    @JsonProperty("discount_type")
+    @ExcludeMissing
+    fun _discountType(): JsonField<DiscountType> = discountType
 
     /** Only available if discount_type is `percentage`. This is a number between 0 and 1. */
     @JsonProperty("percentage_discount")
     @ExcludeMissing
-    fun _percentageDiscount() = percentageDiscount
+    fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
-    @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+    @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -92,15 +94,15 @@ private constructor(
 
     class Builder {
 
-        private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-        private var discountType: JsonField<DiscountType> = JsonMissing.of()
-        private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+        private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+        private var discountType: JsonField<DiscountType>? = null
+        private var percentageDiscount: JsonField<Double>? = null
         private var reason: JsonField<String> = JsonMissing.of()
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(percentageDiscount: PercentageDiscount) = apply {
-            appliesToPriceIds = percentageDiscount.appliesToPriceIds
+            appliesToPriceIds = percentageDiscount.appliesToPriceIds.map { it.toMutableList() }
             discountType = percentageDiscount.discountType
             this.percentageDiscount = percentageDiscount.percentageDiscount
             reason = percentageDiscount.reason
@@ -119,7 +121,24 @@ private constructor(
          * be a subset of prices.
          */
         fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-            this.appliesToPriceIds = appliesToPriceIds
+            this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+        }
+
+        /**
+         * List of price_ids that this discount applies to. For plan/plan phase discounts, this can
+         * be a subset of prices.
+         */
+        fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+            appliesToPriceIds =
+                (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(appliesToPriceId)
+                }
         }
 
         fun discountType(discountType: DiscountType) = discountType(JsonField.of(discountType))
@@ -137,7 +156,9 @@ private constructor(
             this.percentageDiscount = percentageDiscount
         }
 
-        fun reason(reason: String) = reason(JsonField.of(reason))
+        fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+        fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
         fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
@@ -162,9 +183,14 @@ private constructor(
 
         fun build(): PercentageDiscount =
             PercentageDiscount(
-                appliesToPriceIds.map { it.toImmutable() },
-                discountType,
-                percentageDiscount,
+                checkNotNull(appliesToPriceIds) {
+                        "`appliesToPriceIds` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(discountType) { "`discountType` is required but was not set" },
+                checkNotNull(percentageDiscount) {
+                    "`percentageDiscount` is required but was not set"
+                },
                 reason,
                 additionalProperties.toImmutable(),
             )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Plan.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Plan.kt
index d64e13ea..a5a86d04 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Plan.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Plan.kt
@@ -199,26 +199,30 @@ private constructor(
 
     fun version(): Long = version.getRequired("version")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /**
      * Adjustments for this plan. If the plan has phases, this includes adjustments across all
      * phases of the plan.
      */
-    @JsonProperty("adjustments") @ExcludeMissing fun _adjustments() = adjustments
+    @JsonProperty("adjustments")
+    @ExcludeMissing
+    fun _adjustments(): JsonField<List<Adjustment>> = adjustments
 
-    @JsonProperty("base_plan") @ExcludeMissing fun _basePlan() = basePlan
+    @JsonProperty("base_plan") @ExcludeMissing fun _basePlan(): JsonField<BasePlan> = basePlan
 
     /**
      * The parent plan id if the given plan was created by overriding one or more of the parent's
      * prices
      */
-    @JsonProperty("base_plan_id") @ExcludeMissing fun _basePlanId() = basePlanId
+    @JsonProperty("base_plan_id") @ExcludeMissing fun _basePlanId(): JsonField<String> = basePlanId
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /** An ISO 4217 currency string or custom pricing unit (`credits`) for this plan's prices. */
-    @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+    @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
     /**
      * The default memo text on the invoices corresponding to subscriptions on this plan. Note that
@@ -226,40 +230,48 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
-    @JsonProperty("description") @ExcludeMissing fun _description() = description
+    @JsonProperty("description") @ExcludeMissing fun _description(): JsonField<String> = description
 
-    @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+    @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
     /**
      * An optional user-defined ID for this plan resource, used throughout the system as an alias
      * for this Plan. Use this field to identify a plan by an existing identifier in your system.
      */
-    @JsonProperty("external_plan_id") @ExcludeMissing fun _externalPlanId() = externalPlanId
+    @JsonProperty("external_plan_id")
+    @ExcludeMissing
+    fun _externalPlanId(): JsonField<String> = externalPlanId
 
     /**
      * An ISO 4217 currency string for which this plan is billed in. Matches `currency` unless
      * `currency` is a custom pricing unit.
      */
-    @JsonProperty("invoicing_currency") @ExcludeMissing fun _invoicingCurrency() = invoicingCurrency
+    @JsonProperty("invoicing_currency")
+    @ExcludeMissing
+    fun _invoicingCurrency(): JsonField<String> = invoicingCurrency
 
-    @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+    @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-    @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+    @JsonProperty("maximum_amount")
+    @ExcludeMissing
+    fun _maximumAmount(): JsonField<String> = maximumAmount
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-    @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+    @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-    @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+    @JsonProperty("minimum_amount")
+    @ExcludeMissing
+    fun _minimumAmount(): JsonField<String> = minimumAmount
 
-    @JsonProperty("name") @ExcludeMissing fun _name() = name
+    @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
     /**
      * Determines the difference between the invoice issue date and the due date. A value of "0"
@@ -267,23 +279,27 @@ private constructor(
      * customer has a month to pay the invoice before its overdue. Note that individual
      * subscriptions or invoices may set a different net terms configuration.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
-    @JsonProperty("plan_phases") @ExcludeMissing fun _planPhases() = planPhases
+    @JsonProperty("plan_phases")
+    @ExcludeMissing
+    fun _planPhases(): JsonField<List<PlanPhase>> = planPhases
 
     /**
      * Prices for this plan. If the plan has phases, this includes prices across all phases of the
      * plan.
      */
-    @JsonProperty("prices") @ExcludeMissing fun _prices() = prices
+    @JsonProperty("prices") @ExcludeMissing fun _prices(): JsonField<List<Price>> = prices
 
-    @JsonProperty("product") @ExcludeMissing fun _product() = product
+    @JsonProperty("product") @ExcludeMissing fun _product(): JsonField<Product> = product
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_config") @ExcludeMissing fun _trialConfig() = trialConfig
+    @JsonProperty("trial_config")
+    @ExcludeMissing
+    fun _trialConfig(): JsonField<TrialConfig> = trialConfig
 
-    @JsonProperty("version") @ExcludeMissing fun _version() = version
+    @JsonProperty("version") @ExcludeMissing fun _version(): JsonField<Long> = version
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -330,36 +346,36 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var adjustments: JsonField<List<Adjustment>> = JsonMissing.of()
-        private var basePlan: JsonField<BasePlan> = JsonMissing.of()
-        private var basePlanId: JsonField<String> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currency: JsonField<String> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var description: JsonField<String> = JsonMissing.of()
-        private var discount: JsonField<Discount> = JsonMissing.of()
-        private var externalPlanId: JsonField<String> = JsonMissing.of()
-        private var invoicingCurrency: JsonField<String> = JsonMissing.of()
-        private var maximum: JsonField<Maximum> = JsonMissing.of()
-        private var maximumAmount: JsonField<String> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimum: JsonField<Minimum> = JsonMissing.of()
-        private var minimumAmount: JsonField<String> = JsonMissing.of()
-        private var name: JsonField<String> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var planPhases: JsonField<List<PlanPhase>> = JsonMissing.of()
-        private var prices: JsonField<List<Price>> = JsonMissing.of()
-        private var product: JsonField<Product> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialConfig: JsonField<TrialConfig> = JsonMissing.of()
-        private var version: JsonField<Long> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var adjustments: JsonField<MutableList<Adjustment>>? = null
+        private var basePlan: JsonField<BasePlan>? = null
+        private var basePlanId: JsonField<String>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currency: JsonField<String>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var description: JsonField<String>? = null
+        private var discount: JsonField<Discount>? = null
+        private var externalPlanId: JsonField<String>? = null
+        private var invoicingCurrency: JsonField<String>? = null
+        private var maximum: JsonField<Maximum>? = null
+        private var maximumAmount: JsonField<String>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimum: JsonField<Minimum>? = null
+        private var minimumAmount: JsonField<String>? = null
+        private var name: JsonField<String>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var planPhases: JsonField<MutableList<PlanPhase>>? = null
+        private var prices: JsonField<MutableList<Price>>? = null
+        private var product: JsonField<Product>? = null
+        private var status: JsonField<Status>? = null
+        private var trialConfig: JsonField<TrialConfig>? = null
+        private var version: JsonField<Long>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(plan: Plan) = apply {
             id = plan.id
-            adjustments = plan.adjustments
+            adjustments = plan.adjustments.map { it.toMutableList() }
             basePlan = plan.basePlan
             basePlanId = plan.basePlanId
             createdAt = plan.createdAt
@@ -376,8 +392,8 @@ private constructor(
             minimumAmount = plan.minimumAmount
             name = plan.name
             netTerms = plan.netTerms
-            planPhases = plan.planPhases
-            prices = plan.prices
+            planPhases = plan.planPhases.map { it.toMutableList() }
+            prices = plan.prices.map { it.toMutableList() }
             product = plan.product
             status = plan.status
             trialConfig = plan.trialConfig
@@ -400,10 +416,29 @@ private constructor(
          * phases of the plan.
          */
         fun adjustments(adjustments: JsonField<List<Adjustment>>) = apply {
-            this.adjustments = adjustments
+            this.adjustments = adjustments.map { it.toMutableList() }
         }
 
-        fun basePlan(basePlan: BasePlan) = basePlan(JsonField.of(basePlan))
+        /**
+         * Adjustments for this plan. If the plan has phases, this includes adjustments across all
+         * phases of the plan.
+         */
+        fun addAdjustment(adjustment: Adjustment) = apply {
+            adjustments =
+                (adjustments ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustment)
+                }
+        }
+
+        fun basePlan(basePlan: BasePlan?) = basePlan(JsonField.ofNullable(basePlan))
+
+        fun basePlan(basePlan: Optional<BasePlan>) = basePlan(basePlan.orElse(null))
 
         fun basePlan(basePlan: JsonField<BasePlan>) = apply { this.basePlan = basePlan }
 
@@ -411,7 +446,13 @@ private constructor(
          * The parent plan id if the given plan was created by overriding one or more of the
          * parent's prices
          */
-        fun basePlanId(basePlanId: String) = basePlanId(JsonField.of(basePlanId))
+        fun basePlanId(basePlanId: String?) = basePlanId(JsonField.ofNullable(basePlanId))
+
+        /**
+         * The parent plan id if the given plan was created by overriding one or more of the
+         * parent's prices
+         */
+        fun basePlanId(basePlanId: Optional<String>) = basePlanId(basePlanId.orElse(null))
 
         /**
          * The parent plan id if the given plan was created by overriding one or more of the
@@ -437,8 +478,15 @@ private constructor(
          * The default memo text on the invoices corresponding to subscriptions on this plan. Note
          * that each subscription may configure its own memo.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * The default memo text on the invoices corresponding to subscriptions on this plan. Note
+         * that each subscription may configure its own memo.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * The default memo text on the invoices corresponding to subscriptions on this plan. Note
@@ -452,16 +500,39 @@ private constructor(
 
         fun description(description: JsonField<String>) = apply { this.description = description }
 
-        fun discount(discount: Discount) = discount(JsonField.of(discount))
+        fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+        fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
         fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+        fun discount(percentageDiscount: PercentageDiscount) =
+            discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+        fun discount(trialDiscount: TrialDiscount) =
+            discount(Discount.ofTrialDiscount(trialDiscount))
+
+        fun discount(usageDiscount: Discount.UsageDiscount) =
+            discount(Discount.ofUsageDiscount(usageDiscount))
+
+        fun discount(amountDiscount: AmountDiscount) =
+            discount(Discount.ofAmountDiscount(amountDiscount))
+
+        /**
+         * An optional user-defined ID for this plan resource, used throughout the system as an
+         * alias for this Plan. Use this field to identify a plan by an existing identifier in your
+         * system.
+         */
+        fun externalPlanId(externalPlanId: String?) =
+            externalPlanId(JsonField.ofNullable(externalPlanId))
+
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
-        fun externalPlanId(externalPlanId: String) = externalPlanId(JsonField.of(externalPlanId))
+        fun externalPlanId(externalPlanId: Optional<String>) =
+            externalPlanId(externalPlanId.orElse(null))
 
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -487,11 +558,17 @@ private constructor(
             this.invoicingCurrency = invoicingCurrency
         }
 
-        fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+        fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+        fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
         fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-        fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+        fun maximumAmount(maximumAmount: String?) =
+            maximumAmount(JsonField.ofNullable(maximumAmount))
+
+        fun maximumAmount(maximumAmount: Optional<String>) =
+            maximumAmount(maximumAmount.orElse(null))
 
         fun maximumAmount(maximumAmount: JsonField<String>) = apply {
             this.maximumAmount = maximumAmount
@@ -511,11 +588,17 @@ private constructor(
          */
         fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-        fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+        fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+        fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
         fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-        fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+        fun minimumAmount(minimumAmount: String?) =
+            minimumAmount(JsonField.ofNullable(minimumAmount))
+
+        fun minimumAmount(minimumAmount: Optional<String>) =
+            minimumAmount(minimumAmount.orElse(null))
 
         fun minimumAmount(minimumAmount: JsonField<String>) = apply {
             this.minimumAmount = minimumAmount
@@ -531,7 +614,24 @@ private constructor(
          * customer has a month to pay the invoice before its overdue. Note that individual
          * subscriptions or invoices may set a different net terms configuration.
          */
-        fun netTerms(netTerms: Long) = netTerms(JsonField.of(netTerms))
+        fun netTerms(netTerms: Long?) = netTerms(JsonField.ofNullable(netTerms))
+
+        /**
+         * Determines the difference between the invoice issue date and the due date. A value of "0"
+         * here signifies that invoices are due on issue, whereas a value of "30" means that the
+         * customer has a month to pay the invoice before its overdue. Note that individual
+         * subscriptions or invoices may set a different net terms configuration.
+         */
+        fun netTerms(netTerms: Long) = netTerms(netTerms as Long?)
+
+        /**
+         * Determines the difference between the invoice issue date and the due date. A value of "0"
+         * here signifies that invoices are due on issue, whereas a value of "30" means that the
+         * customer has a month to pay the invoice before its overdue. Note that individual
+         * subscriptions or invoices may set a different net terms configuration.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
         /**
          * Determines the difference between the invoice issue date and the due date. A value of "0"
@@ -541,10 +641,25 @@ private constructor(
          */
         fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
 
-        fun planPhases(planPhases: List<PlanPhase>) = planPhases(JsonField.of(planPhases))
+        fun planPhases(planPhases: List<PlanPhase>?) = planPhases(JsonField.ofNullable(planPhases))
+
+        fun planPhases(planPhases: Optional<List<PlanPhase>>) = planPhases(planPhases.orElse(null))
 
         fun planPhases(planPhases: JsonField<List<PlanPhase>>) = apply {
-            this.planPhases = planPhases
+            this.planPhases = planPhases.map { it.toMutableList() }
+        }
+
+        fun addPlanPhase(planPhase: PlanPhase) = apply {
+            planPhases =
+                (planPhases ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(planPhase)
+                }
         }
 
         /**
@@ -557,7 +672,26 @@ private constructor(
          * Prices for this plan. If the plan has phases, this includes prices across all phases of
          * the plan.
          */
-        fun prices(prices: JsonField<List<Price>>) = apply { this.prices = prices }
+        fun prices(prices: JsonField<List<Price>>) = apply {
+            this.prices = prices.map { it.toMutableList() }
+        }
+
+        /**
+         * Prices for this plan. If the plan has phases, this includes prices across all phases of
+         * the plan.
+         */
+        fun addPrice(price: Price) = apply {
+            prices =
+                (prices ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(price)
+                }
+        }
 
         fun product(product: Product) = product(JsonField.of(product))
 
@@ -598,30 +732,37 @@ private constructor(
 
         fun build(): Plan =
             Plan(
-                id,
-                adjustments.map { it.toImmutable() },
-                basePlan,
-                basePlanId,
-                createdAt,
-                currency,
-                defaultInvoiceMemo,
-                description,
-                discount,
-                externalPlanId,
-                invoicingCurrency,
-                maximum,
-                maximumAmount,
-                metadata,
-                minimum,
-                minimumAmount,
-                name,
-                netTerms,
-                planPhases.map { it.toImmutable() },
-                prices.map { it.toImmutable() },
-                product,
-                status,
-                trialConfig,
-                version,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(adjustments) { "`adjustments` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(basePlan) { "`basePlan` is required but was not set" },
+                checkNotNull(basePlanId) { "`basePlanId` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currency) { "`currency` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(description) { "`description` is required but was not set" },
+                checkNotNull(discount) { "`discount` is required but was not set" },
+                checkNotNull(externalPlanId) { "`externalPlanId` is required but was not set" },
+                checkNotNull(invoicingCurrency) {
+                    "`invoicingCurrency` is required but was not set"
+                },
+                checkNotNull(maximum) { "`maximum` is required but was not set" },
+                checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimum) { "`minimum` is required but was not set" },
+                checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                checkNotNull(name) { "`name` is required but was not set" },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(planPhases) { "`planPhases` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(prices) { "`prices` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(product) { "`product` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialConfig) { "`trialConfig` is required but was not set" },
+                checkNotNull(version) { "`version` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -913,32 +1054,40 @@ private constructor(
             /** The reason for the adjustment. */
             fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("adjustment_type") @ExcludeMissing fun _adjustmentType() = adjustmentType
+            @JsonProperty("adjustment_type")
+            @ExcludeMissing
+            fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
             /**
              * The amount by which to discount the prices this adjustment applies to in a given
              * billing period.
              */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price IDs that this adjustment applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /**
              * True for adjustments that apply to an entire invocice, false for adjustments that
              * apply to only one price.
              */
-            @JsonProperty("is_invoice_level") @ExcludeMissing fun _isInvoiceLevel() = isInvoiceLevel
+            @JsonProperty("is_invoice_level")
+            @ExcludeMissing
+            fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
             /** The plan phase in which this adjustment is active. */
-            @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+            @JsonProperty("plan_phase_order")
+            @ExcludeMissing
+            fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
             /** The reason for the adjustment. */
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -968,13 +1117,13 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                private var reason: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var adjustmentType: JsonField<AdjustmentType>? = null
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var isInvoiceLevel: JsonField<Boolean>? = null
+                private var planPhaseOrder: JsonField<Long>? = null
+                private var reason: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -982,7 +1131,8 @@ private constructor(
                     id = amountDiscountAdjustment.id
                     adjustmentType = amountDiscountAdjustment.adjustmentType
                     amountDiscount = amountDiscountAdjustment.amountDiscount
-                    appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                    appliesToPriceIds =
+                        amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                     isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                     planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                     reason = amountDiscountAdjustment.reason
@@ -1022,7 +1172,21 @@ private constructor(
 
                 /** The price IDs that this adjustment applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price IDs that this adjustment applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /**
@@ -1041,8 +1205,16 @@ private constructor(
                 }
 
                 /** The plan phase in which this adjustment is active. */
-                fun planPhaseOrder(planPhaseOrder: Long) =
-                    planPhaseOrder(JsonField.of(planPhaseOrder))
+                fun planPhaseOrder(planPhaseOrder: Long?) =
+                    planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+                /** The plan phase in which this adjustment is active. */
+                fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+                /** The plan phase in which this adjustment is active. */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                    planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                 /** The plan phase in which this adjustment is active. */
                 fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1050,7 +1222,10 @@ private constructor(
                 }
 
                 /** The reason for the adjustment. */
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                /** The reason for the adjustment. */
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 /** The reason for the adjustment. */
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1079,13 +1254,24 @@ private constructor(
 
                 fun build(): AmountDiscountAdjustment =
                     AmountDiscountAdjustment(
-                        id,
-                        adjustmentType,
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        isInvoiceLevel,
-                        planPhaseOrder,
-                        reason,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(adjustmentType) {
+                            "`adjustmentType` is required but was not set"
+                        },
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(isInvoiceLevel) {
+                            "`isInvoiceLevel` is required but was not set"
+                        },
+                        checkNotNull(planPhaseOrder) {
+                            "`planPhaseOrder` is required but was not set"
+                        },
+                        checkNotNull(reason) { "`reason` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1215,20 +1401,24 @@ private constructor(
             /** The reason for the adjustment. */
             fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("adjustment_type") @ExcludeMissing fun _adjustmentType() = adjustmentType
+            @JsonProperty("adjustment_type")
+            @ExcludeMissing
+            fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
             /** The price IDs that this adjustment applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /**
              * True for adjustments that apply to an entire invocice, false for adjustments that
              * apply to only one price.
              */
-            @JsonProperty("is_invoice_level") @ExcludeMissing fun _isInvoiceLevel() = isInvoiceLevel
+            @JsonProperty("is_invoice_level")
+            @ExcludeMissing
+            fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
             /**
              * The percentage (as a value between 0 and 1) by which to discount the price intervals
@@ -1236,13 +1426,15 @@ private constructor(
              */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The plan phase in which this adjustment is active. */
-            @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+            @JsonProperty("plan_phase_order")
+            @ExcludeMissing
+            fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
             /** The reason for the adjustment. */
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1272,13 +1464,13 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                private var reason: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var adjustmentType: JsonField<AdjustmentType>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var isInvoiceLevel: JsonField<Boolean>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var planPhaseOrder: JsonField<Long>? = null
+                private var reason: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1286,7 +1478,10 @@ private constructor(
                     apply {
                         id = percentageDiscountAdjustment.id
                         adjustmentType = percentageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            percentageDiscountAdjustment.appliesToPriceIds.map {
+                                it.toMutableList()
+                            }
                         isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                         percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                         planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1312,7 +1507,21 @@ private constructor(
 
                 /** The price IDs that this adjustment applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price IDs that this adjustment applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /**
@@ -1346,8 +1555,16 @@ private constructor(
                 }
 
                 /** The plan phase in which this adjustment is active. */
-                fun planPhaseOrder(planPhaseOrder: Long) =
-                    planPhaseOrder(JsonField.of(planPhaseOrder))
+                fun planPhaseOrder(planPhaseOrder: Long?) =
+                    planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+                /** The plan phase in which this adjustment is active. */
+                fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+                /** The plan phase in which this adjustment is active. */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                    planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                 /** The plan phase in which this adjustment is active. */
                 fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1355,7 +1572,10 @@ private constructor(
                 }
 
                 /** The reason for the adjustment. */
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                /** The reason for the adjustment. */
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 /** The reason for the adjustment. */
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1384,13 +1604,24 @@ private constructor(
 
                 fun build(): PercentageDiscountAdjustment =
                     PercentageDiscountAdjustment(
-                        id,
-                        adjustmentType,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        isInvoiceLevel,
-                        percentageDiscount,
-                        planPhaseOrder,
-                        reason,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(adjustmentType) {
+                            "`adjustmentType` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(isInvoiceLevel) {
+                            "`isInvoiceLevel` is required but was not set"
+                        },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(planPhaseOrder) {
+                            "`planPhaseOrder` is required but was not set"
+                        },
+                        checkNotNull(reason) { "`reason` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1520,32 +1751,40 @@ private constructor(
              */
             fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("adjustment_type") @ExcludeMissing fun _adjustmentType() = adjustmentType
+            @JsonProperty("adjustment_type")
+            @ExcludeMissing
+            fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
             /** The price IDs that this adjustment applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /**
              * True for adjustments that apply to an entire invocice, false for adjustments that
              * apply to only one price.
              */
-            @JsonProperty("is_invoice_level") @ExcludeMissing fun _isInvoiceLevel() = isInvoiceLevel
+            @JsonProperty("is_invoice_level")
+            @ExcludeMissing
+            fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
             /** The plan phase in which this adjustment is active. */
-            @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+            @JsonProperty("plan_phase_order")
+            @ExcludeMissing
+            fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
             /** The reason for the adjustment. */
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             /**
              * The number of usage units by which to discount the price this adjustment applies to
              * in a given billing period.
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1575,20 +1814,21 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                private var reason: JsonField<String> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var adjustmentType: JsonField<AdjustmentType>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var isInvoiceLevel: JsonField<Boolean>? = null
+                private var planPhaseOrder: JsonField<Long>? = null
+                private var reason: JsonField<String>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                     id = usageDiscountAdjustment.id
                     adjustmentType = usageDiscountAdjustment.adjustmentType
-                    appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                    appliesToPriceIds =
+                        usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                     isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                     planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                     reason = usageDiscountAdjustment.reason
@@ -1614,7 +1854,21 @@ private constructor(
 
                 /** The price IDs that this adjustment applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price IDs that this adjustment applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /**
@@ -1633,8 +1887,16 @@ private constructor(
                 }
 
                 /** The plan phase in which this adjustment is active. */
-                fun planPhaseOrder(planPhaseOrder: Long) =
-                    planPhaseOrder(JsonField.of(planPhaseOrder))
+                fun planPhaseOrder(planPhaseOrder: Long?) =
+                    planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+                /** The plan phase in which this adjustment is active. */
+                fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+                /** The plan phase in which this adjustment is active. */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                    planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                 /** The plan phase in which this adjustment is active. */
                 fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1642,7 +1904,10 @@ private constructor(
                 }
 
                 /** The reason for the adjustment. */
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                /** The reason for the adjustment. */
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 /** The reason for the adjustment. */
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1686,13 +1951,24 @@ private constructor(
 
                 fun build(): UsageDiscountAdjustment =
                     UsageDiscountAdjustment(
-                        id,
-                        adjustmentType,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        isInvoiceLevel,
-                        planPhaseOrder,
-                        reason,
-                        usageDiscount,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(adjustmentType) {
+                            "`adjustmentType` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(isInvoiceLevel) {
+                            "`isInvoiceLevel` is required but was not set"
+                        },
+                        checkNotNull(planPhaseOrder) {
+                            "`planPhaseOrder` is required but was not set"
+                        },
+                        checkNotNull(reason) { "`reason` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1828,35 +2104,43 @@ private constructor(
             /** The reason for the adjustment. */
             fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("adjustment_type") @ExcludeMissing fun _adjustmentType() = adjustmentType
+            @JsonProperty("adjustment_type")
+            @ExcludeMissing
+            fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
             /** The price IDs that this adjustment applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /**
              * True for adjustments that apply to an entire invocice, false for adjustments that
              * apply to only one price.
              */
-            @JsonProperty("is_invoice_level") @ExcludeMissing fun _isInvoiceLevel() = isInvoiceLevel
+            @JsonProperty("is_invoice_level")
+            @ExcludeMissing
+            fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
             /** The item ID that revenue from this minimum will be attributed to. */
-            @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
             /**
              * The minimum amount to charge in a given billing period for the prices this adjustment
              * applies to.
              */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             /** The plan phase in which this adjustment is active. */
-            @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+            @JsonProperty("plan_phase_order")
+            @ExcludeMissing
+            fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
             /** The reason for the adjustment. */
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1887,21 +2171,22 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                private var itemId: JsonField<String> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
-                private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                private var reason: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var adjustmentType: JsonField<AdjustmentType>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var isInvoiceLevel: JsonField<Boolean>? = null
+                private var itemId: JsonField<String>? = null
+                private var minimumAmount: JsonField<String>? = null
+                private var planPhaseOrder: JsonField<Long>? = null
+                private var reason: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                     id = minimumAdjustment.id
                     adjustmentType = minimumAdjustment.adjustmentType
-                    appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                    appliesToPriceIds =
+                        minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                     isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                     itemId = minimumAdjustment.itemId
                     minimumAmount = minimumAdjustment.minimumAmount
@@ -1927,7 +2212,21 @@ private constructor(
 
                 /** The price IDs that this adjustment applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price IDs that this adjustment applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /**
@@ -1967,8 +2266,16 @@ private constructor(
                 }
 
                 /** The plan phase in which this adjustment is active. */
-                fun planPhaseOrder(planPhaseOrder: Long) =
-                    planPhaseOrder(JsonField.of(planPhaseOrder))
+                fun planPhaseOrder(planPhaseOrder: Long?) =
+                    planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+                /** The plan phase in which this adjustment is active. */
+                fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+                /** The plan phase in which this adjustment is active. */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                    planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                 /** The plan phase in which this adjustment is active. */
                 fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1976,7 +2283,10 @@ private constructor(
                 }
 
                 /** The reason for the adjustment. */
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                /** The reason for the adjustment. */
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 /** The reason for the adjustment. */
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2005,14 +2315,25 @@ private constructor(
 
                 fun build(): MinimumAdjustment =
                     MinimumAdjustment(
-                        id,
-                        adjustmentType,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        isInvoiceLevel,
-                        itemId,
-                        minimumAmount,
-                        planPhaseOrder,
-                        reason,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(adjustmentType) {
+                            "`adjustmentType` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(isInvoiceLevel) {
+                            "`isInvoiceLevel` is required but was not set"
+                        },
+                        checkNotNull(itemId) { "`itemId` is required but was not set" },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
+                        checkNotNull(planPhaseOrder) {
+                            "`planPhaseOrder` is required but was not set"
+                        },
+                        checkNotNull(reason) { "`reason` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2142,32 +2463,40 @@ private constructor(
             /** The reason for the adjustment. */
             fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("adjustment_type") @ExcludeMissing fun _adjustmentType() = adjustmentType
+            @JsonProperty("adjustment_type")
+            @ExcludeMissing
+            fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
             /** The price IDs that this adjustment applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /**
              * True for adjustments that apply to an entire invocice, false for adjustments that
              * apply to only one price.
              */
-            @JsonProperty("is_invoice_level") @ExcludeMissing fun _isInvoiceLevel() = isInvoiceLevel
+            @JsonProperty("is_invoice_level")
+            @ExcludeMissing
+            fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
             /**
              * The maximum amount to charge in a given billing period for the prices this adjustment
              * applies to.
              */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             /** The plan phase in which this adjustment is active. */
-            @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+            @JsonProperty("plan_phase_order")
+            @ExcludeMissing
+            fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
             /** The reason for the adjustment. */
-            @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+            @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2197,20 +2526,21 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
-                private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                private var reason: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var adjustmentType: JsonField<AdjustmentType>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var isInvoiceLevel: JsonField<Boolean>? = null
+                private var maximumAmount: JsonField<String>? = null
+                private var planPhaseOrder: JsonField<Long>? = null
+                private var reason: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                     id = maximumAdjustment.id
                     adjustmentType = maximumAdjustment.adjustmentType
-                    appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                    appliesToPriceIds =
+                        maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                     isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                     maximumAmount = maximumAdjustment.maximumAmount
                     planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2235,7 +2565,21 @@ private constructor(
 
                 /** The price IDs that this adjustment applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price IDs that this adjustment applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /**
@@ -2269,8 +2613,16 @@ private constructor(
                 }
 
                 /** The plan phase in which this adjustment is active. */
-                fun planPhaseOrder(planPhaseOrder: Long) =
-                    planPhaseOrder(JsonField.of(planPhaseOrder))
+                fun planPhaseOrder(planPhaseOrder: Long?) =
+                    planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+                /** The plan phase in which this adjustment is active. */
+                fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+                /** The plan phase in which this adjustment is active. */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                    planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                 /** The plan phase in which this adjustment is active. */
                 fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2278,7 +2630,10 @@ private constructor(
                 }
 
                 /** The reason for the adjustment. */
-                fun reason(reason: String) = reason(JsonField.of(reason))
+                fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                /** The reason for the adjustment. */
+                fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                 /** The reason for the adjustment. */
                 fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2307,13 +2662,24 @@ private constructor(
 
                 fun build(): MaximumAdjustment =
                     MaximumAdjustment(
-                        id,
-                        adjustmentType,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        isInvoiceLevel,
-                        maximumAmount,
-                        planPhaseOrder,
-                        reason,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(adjustmentType) {
+                            "`adjustmentType` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(isInvoiceLevel) {
+                            "`isInvoiceLevel` is required but was not set"
+                        },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
+                        checkNotNull(planPhaseOrder) {
+                            "`planPhaseOrder` is required but was not set"
+                        },
+                        checkNotNull(reason) { "`reason` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2415,16 +2781,18 @@ private constructor(
 
         fun name(): Optional<String> = Optional.ofNullable(name.getNullable("name"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
-        @JsonProperty("external_plan_id") @ExcludeMissing fun _externalPlanId() = externalPlanId
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2450,9 +2818,9 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalPlanId: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalPlanId: JsonField<String>? = null
+            private var name: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -2463,7 +2831,9 @@ private constructor(
                 additionalProperties = basePlan.additionalProperties.toMutableMap()
             }
 
-            fun id(id: String) = id(JsonField.of(id))
+            fun id(id: String?) = id(JsonField.ofNullable(id))
+
+            fun id(id: Optional<String>) = id(id.orElse(null))
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
@@ -2472,8 +2842,16 @@ private constructor(
              * alias for this Plan. Use this field to identify a plan by an existing identifier in
              * your system.
              */
-            fun externalPlanId(externalPlanId: String) =
-                externalPlanId(JsonField.of(externalPlanId))
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
+
+            /**
+             * An optional user-defined ID for this plan resource, used throughout the system as an
+             * alias for this Plan. Use this field to identify a plan by an existing identifier in
+             * your system.
+             */
+            fun externalPlanId(externalPlanId: Optional<String>) =
+                externalPlanId(externalPlanId.orElse(null))
 
             /**
              * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -2484,7 +2862,9 @@ private constructor(
                 this.externalPlanId = externalPlanId
             }
 
-            fun name(name: String) = name(JsonField.of(name))
+            fun name(name: String?) = name(JsonField.ofNullable(name))
+
+            fun name(name: Optional<String>) = name(name.orElse(null))
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
@@ -2509,9 +2889,9 @@ private constructor(
 
             fun build(): BasePlan =
                 BasePlan(
-                    id,
-                    externalPlanId,
-                    name,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalPlanId) { "`externalPlanId` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2564,10 +2944,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Maximum amount applied */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2592,13 +2974,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var maximumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximum: Maximum) = apply {
-                appliesToPriceIds = maximum.appliesToPriceIds
+                appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                 maximumAmount = maximum.maximumAmount
                 additionalProperties = maximum.additionalProperties.toMutableMap()
             }
@@ -2615,7 +2997,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this maximum amount applies to. For plan/plan phase maximums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Maximum amount applied */
@@ -2647,8 +3046,11 @@ private constructor(
 
             fun build(): Maximum =
                 Maximum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    maximumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2781,10 +3183,12 @@ private constructor(
          */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** Minimum amount applied */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2809,13 +3213,13 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var minimumAmount: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimum: Minimum) = apply {
-                appliesToPriceIds = minimum.appliesToPriceIds
+                appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                 minimumAmount = minimum.minimumAmount
                 additionalProperties = minimum.additionalProperties.toMutableMap()
             }
@@ -2832,7 +3236,24 @@ private constructor(
              * this can be a subset of prices.
              */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /**
+             * List of price_ids that this minimum amount applies to. For plan/plan phase minimums,
+             * this can be a subset of prices.
+             */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** Minimum amount applied */
@@ -2864,8 +3285,11 @@ private constructor(
 
             fun build(): Minimum =
                 Minimum(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    minimumAmount,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -2958,32 +3382,40 @@ private constructor(
         /** Determines the ordering of the phase in a plan's lifecycle. 1 = first phase. */
         fun order(): Long = order.getRequired("order")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("description") @ExcludeMissing fun _description() = description
+        @JsonProperty("description")
+        @ExcludeMissing
+        fun _description(): JsonField<String> = description
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
         /**
          * How many terms of length `duration_unit` this phase is active for. If null, this phase is
          * evergreen and active indefinitely
          */
-        @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+        @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-        @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+        @JsonProperty("duration_unit")
+        @ExcludeMissing
+        fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** Determines the ordering of the phase in a plan's lifecycle. 1 = first phase. */
-        @JsonProperty("order") @ExcludeMissing fun _order() = order
+        @JsonProperty("order") @ExcludeMissing fun _order(): JsonField<Long> = order
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3017,17 +3449,17 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var description: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var duration: JsonField<Long> = JsonMissing.of()
-            private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var order: JsonField<Long> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var description: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var duration: JsonField<Long>? = null
+            private var durationUnit: JsonField<DurationUnit>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var order: JsonField<Long>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3050,21 +3482,50 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun description(description: String) = description(JsonField.of(description))
+            fun description(description: String?) = description(JsonField.ofNullable(description))
+
+            fun description(description: Optional<String>) = description(description.orElse(null))
 
             fun description(description: JsonField<String>) = apply {
                 this.description = description
             }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            /**
+             * How many terms of length `duration_unit` this phase is active for. If null, this
+             * phase is evergreen and active indefinitely
+             */
+            fun duration(duration: Long?) = duration(JsonField.ofNullable(duration))
+
+            /**
+             * How many terms of length `duration_unit` this phase is active for. If null, this
+             * phase is evergreen and active indefinitely
+             */
+            fun duration(duration: Long) = duration(duration as Long?)
+
             /**
              * How many terms of length `duration_unit` this phase is active for. If null, this
              * phase is evergreen and active indefinitely
              */
-            fun duration(duration: Long) = duration(JsonField.of(duration))
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun duration(duration: Optional<Long>) = duration(duration.orElse(null) as Long?)
 
             /**
              * How many terms of length `duration_unit` this phase is active for. If null, this
@@ -3072,27 +3533,43 @@ private constructor(
              */
             fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
-            fun durationUnit(durationUnit: DurationUnit) = durationUnit(JsonField.of(durationUnit))
+            fun durationUnit(durationUnit: DurationUnit?) =
+                durationUnit(JsonField.ofNullable(durationUnit))
+
+            fun durationUnit(durationUnit: Optional<DurationUnit>) =
+                durationUnit(durationUnit.orElse(null))
 
             fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                 this.durationUnit = durationUnit
             }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
             }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -3129,17 +3606,17 @@ private constructor(
 
             fun build(): PlanPhase =
                 PlanPhase(
-                    id,
-                    description,
-                    discount,
-                    duration,
-                    durationUnit,
-                    maximum,
-                    maximumAmount,
-                    minimum,
-                    minimumAmount,
-                    name,
-                    order,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(description) { "`description` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(duration) { "`duration` is required but was not set" },
+                    checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(order) { "`order` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3249,10 +3726,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3277,13 +3756,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -3300,7 +3779,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -3336,8 +3832,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3390,10 +3891,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3418,13 +3921,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -3441,7 +3944,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -3477,8 +3997,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3540,11 +4065,13 @@ private constructor(
 
         fun name(): String = name.getRequired("name")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3570,9 +4097,9 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var name: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3618,9 +4145,9 @@ private constructor(
 
             fun build(): Product =
                 Product(
-                    id,
-                    createdAt,
-                    name,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3725,9 +4252,13 @@ private constructor(
 
         fun trialPeriodUnit(): TrialPeriodUnit = trialPeriodUnit.getRequired("trial_period_unit")
 
-        @JsonProperty("trial_period") @ExcludeMissing fun _trialPeriod() = trialPeriod
+        @JsonProperty("trial_period")
+        @ExcludeMissing
+        fun _trialPeriod(): JsonField<Long> = trialPeriod
 
-        @JsonProperty("trial_period_unit") @ExcludeMissing fun _trialPeriodUnit() = trialPeriodUnit
+        @JsonProperty("trial_period_unit")
+        @ExcludeMissing
+        fun _trialPeriodUnit(): JsonField<TrialPeriodUnit> = trialPeriodUnit
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3752,8 +4283,8 @@ private constructor(
 
         class Builder {
 
-            private var trialPeriod: JsonField<Long> = JsonMissing.of()
-            private var trialPeriodUnit: JsonField<TrialPeriodUnit> = JsonMissing.of()
+            private var trialPeriod: JsonField<Long>? = null
+            private var trialPeriodUnit: JsonField<TrialPeriodUnit>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3763,7 +4294,13 @@ private constructor(
                 additionalProperties = trialConfig.additionalProperties.toMutableMap()
             }
 
-            fun trialPeriod(trialPeriod: Long) = trialPeriod(JsonField.of(trialPeriod))
+            fun trialPeriod(trialPeriod: Long?) = trialPeriod(JsonField.ofNullable(trialPeriod))
+
+            fun trialPeriod(trialPeriod: Long) = trialPeriod(trialPeriod as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun trialPeriod(trialPeriod: Optional<Long>) =
+                trialPeriod(trialPeriod.orElse(null) as Long?)
 
             fun trialPeriod(trialPeriod: JsonField<Long>) = apply { this.trialPeriod = trialPeriod }
 
@@ -3795,8 +4332,10 @@ private constructor(
 
             fun build(): TrialConfig =
                 TrialConfig(
-                    trialPeriod,
-                    trialPeriodUnit,
+                    checkNotNull(trialPeriod) { "`trialPeriod` is required but was not set" },
+                    checkNotNull(trialPeriodUnit) {
+                        "`trialPeriodUnit` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanCreateParams.kt
index ff338b26..9b2d17bf 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanCreateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,7 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/** This endpoint allows creation of plans including their prices. */
 class PlanCreateParams
 constructor(
     private val body: PlanCreateBody,
@@ -72,12 +74,47 @@ constructor(
      */
     fun status(): Optional<Status> = body.status()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
+    fun _currency(): JsonField<String> = body._currency()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    fun _name(): JsonField<String> = body._name()
+
+    /**
+     * Prices for this plan. If the plan has phases, this includes prices across all phases of the
+     * plan.
+     */
+    fun _prices(): JsonField<List<Price>> = body._prices()
+
+    /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+    fun _defaultInvoiceMemo(): JsonField<String> = body._defaultInvoiceMemo()
+
+    fun _externalPlanId(): JsonField<String> = body._externalPlanId()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /**
+     * The net terms determines the difference between the invoice date and the issue date for the
+     * invoice. If you intend the invoice to be due on issue, set this to 0.
+     */
+    fun _netTerms(): JsonField<Long> = body._netTerms()
+
+    /**
+     * The status of the plan to create (either active or draft). If not specified, this defaults to
+     * active.
+     */
+    fun _status(): JsonField<Status> = body._status()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): PlanCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -88,59 +125,130 @@ constructor(
     class PlanCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("prices") private val prices: List<Price>,
-        @JsonProperty("default_invoice_memo") private val defaultInvoiceMemo: String?,
-        @JsonProperty("external_plan_id") private val externalPlanId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("net_terms") private val netTerms: Long?,
-        @JsonProperty("status") private val status: Status?,
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("prices")
+        @ExcludeMissing
+        private val prices: JsonField<List<Price>> = JsonMissing.of(),
+        @JsonProperty("default_invoice_memo")
+        @ExcludeMissing
+        private val defaultInvoiceMemo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        private val externalPlanId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("status")
+        @ExcludeMissing
+        private val status: JsonField<Status> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
+
+        fun name(): String = name.getRequired("name")
+
+        /**
+         * Prices for this plan. If the plan has phases, this includes prices across all phases of
+         * the plan.
+         */
+        fun prices(): List<Price> = prices.getRequired("prices")
+
+        /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+        fun defaultInvoiceMemo(): Optional<String> =
+            Optional.ofNullable(defaultInvoiceMemo.getNullable("default_invoice_memo"))
+
+        fun externalPlanId(): Optional<String> =
+            Optional.ofNullable(externalPlanId.getNullable("external_plan_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0.
+         */
+        fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms.getNullable("net_terms"))
+
+        /**
+         * The status of the plan to create (either active or draft). If not specified, this
+         * defaults to active.
+         */
+        fun status(): Optional<Status> = Optional.ofNullable(status.getNullable("status"))
+
+        /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /**
          * Prices for this plan. If the plan has phases, this includes prices across all phases of
          * the plan.
          */
-        @JsonProperty("prices") fun prices(): List<Price> = prices
+        @JsonProperty("prices") @ExcludeMissing fun _prices(): JsonField<List<Price>> = prices
 
         /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
         @JsonProperty("default_invoice_memo")
-        fun defaultInvoiceMemo(): Optional<String> = Optional.ofNullable(defaultInvoiceMemo)
+        @ExcludeMissing
+        fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
         @JsonProperty("external_plan_id")
-        fun externalPlanId(): Optional<String> = Optional.ofNullable(externalPlanId)
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
          */
-        @JsonProperty("net_terms") fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms)
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         /**
          * The status of the plan to create (either active or draft). If not specified, this
          * defaults to active.
          */
-        @JsonProperty("status") fun status(): Optional<Status> = Optional.ofNullable(status)
+        @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PlanCreateBody = apply {
+            if (!validated) {
+                currency()
+                name()
+                prices()
+                defaultInvoiceMemo()
+                externalPlanId()
+                metadata().map { it.validate() }
+                netTerms()
+                status()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -150,21 +258,21 @@ constructor(
 
         class Builder {
 
-            private var currency: String? = null
-            private var name: String? = null
-            private var prices: MutableList<Price>? = null
-            private var defaultInvoiceMemo: String? = null
-            private var externalPlanId: String? = null
-            private var metadata: Metadata? = null
-            private var netTerms: Long? = null
-            private var status: Status? = null
+            private var currency: JsonField<String>? = null
+            private var name: JsonField<String>? = null
+            private var prices: JsonField<MutableList<Price>>? = null
+            private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
+            private var externalPlanId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var status: JsonField<Status> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(planCreateBody: PlanCreateBody) = apply {
                 currency = planCreateBody.currency
                 name = planCreateBody.name
-                prices = planCreateBody.prices.toMutableList()
+                prices = planCreateBody.prices.map { it.toMutableList() }
                 defaultInvoiceMemo = planCreateBody.defaultInvoiceMemo
                 externalPlanId = planCreateBody.externalPlanId
                 metadata = planCreateBody.metadata
@@ -174,46 +282,75 @@ constructor(
             }
 
             /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            fun name(name: String) = name(JsonField.of(name))
 
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            /**
+             * Prices for this plan. If the plan has phases, this includes prices across all phases
+             * of the plan.
+             */
+            fun prices(prices: List<Price>) = prices(JsonField.of(prices))
 
             /**
              * Prices for this plan. If the plan has phases, this includes prices across all phases
              * of the plan.
              */
-            fun prices(prices: List<Price>) = apply { this.prices = prices.toMutableList() }
+            fun prices(prices: JsonField<List<Price>>) = apply {
+                this.prices = prices.map { it.toMutableList() }
+            }
 
             /**
              * Prices for this plan. If the plan has phases, this includes prices across all phases
              * of the plan.
              */
             fun addPrice(price: Price) = apply {
-                prices = (prices ?: mutableListOf()).apply { add(price) }
+                prices =
+                    (prices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(price)
+                    }
             }
 
             /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
-            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) = apply {
-                this.defaultInvoiceMemo = defaultInvoiceMemo
-            }
+            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+                defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
 
             /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
             fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
                 defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
-            fun externalPlanId(externalPlanId: String?) = apply {
-                this.externalPlanId = externalPlanId
+            /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+            fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+                this.defaultInvoiceMemo = defaultInvoiceMemo
             }
 
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
+
             fun externalPlanId(externalPlanId: Optional<String>) =
                 externalPlanId(externalPlanId.orElse(null))
 
+            fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+                this.externalPlanId = externalPlanId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -222,11 +359,18 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0.
              */
-            fun netTerms(netTerms: Long?) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long?) = netTerms(JsonField.ofNullable(netTerms))
 
             /**
              * The net terms determines the difference between the invoice date and the issue date
@@ -241,17 +385,23 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
+
             /**
              * The status of the plan to create (either active or draft). If not specified, this
              * defaults to active.
              */
-            fun status(status: Status?) = apply { this.status = status }
+            fun status(status: Status) = status(JsonField.of(status))
 
             /**
              * The status of the plan to create (either active or draft). If not specified, this
              * defaults to active.
              */
-            fun status(status: Optional<Status>) = status(status.orElse(null))
+            fun status(status: JsonField<Status>) = apply { this.status = status }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -276,7 +426,8 @@ constructor(
                 PlanCreateBody(
                     checkNotNull(currency) { "`currency` is required but was not set" },
                     checkNotNull(name) { "`name` is required but was not set" },
-                    checkNotNull(prices) { "`prices` is required but was not set" }.toImmutable(),
+                    checkNotNull(prices) { "`prices` is required but was not set" }
+                        .map { it.toImmutable() },
                     defaultInvoiceMemo,
                     externalPlanId,
                     metadata,
@@ -328,14 +479,25 @@ constructor(
         /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
         fun currency(currency: String) = apply { body.currency(currency) }
 
+        /** An ISO 4217 currency string for invoices generated by subscriptions on this plan. */
+        fun currency(currency: JsonField<String>) = apply { body.currency(currency) }
+
         fun name(name: String) = apply { body.name(name) }
 
+        fun name(name: JsonField<String>) = apply { body.name(name) }
+
         /**
          * Prices for this plan. If the plan has phases, this includes prices across all phases of
          * the plan.
          */
         fun prices(prices: List<Price>) = apply { body.prices(prices) }
 
+        /**
+         * Prices for this plan. If the plan has phases, this includes prices across all phases of
+         * the plan.
+         */
+        fun prices(prices: JsonField<List<Price>>) = apply { body.prices(prices) }
+
         /**
          * Prices for this plan. If the plan has phases, this includes prices across all phases of
          * the plan.
@@ -351,11 +513,20 @@ constructor(
         fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
             defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+        /** Free-form text which is available on the invoice PDF and the Orb invoice portal. */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+            body.defaultInvoiceMemo(defaultInvoiceMemo)
+        }
+
         fun externalPlanId(externalPlanId: String?) = apply { body.externalPlanId(externalPlanId) }
 
         fun externalPlanId(externalPlanId: Optional<String>) =
             externalPlanId(externalPlanId.orElse(null))
 
+        fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+            body.externalPlanId(externalPlanId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -370,6 +541,13 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0.
@@ -389,17 +567,42 @@ constructor(
         @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
         fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0.
+         */
+        fun netTerms(netTerms: JsonField<Long>) = apply { body.netTerms(netTerms) }
+
         /**
          * The status of the plan to create (either active or draft). If not specified, this
          * defaults to active.
          */
-        fun status(status: Status?) = apply { body.status(status) }
+        fun status(status: Status) = apply { body.status(status) }
 
         /**
          * The status of the plan to create (either active or draft). If not specified, this
          * defaults to active.
          */
-        fun status(status: Optional<Status>) = status(status.orElse(null))
+        fun status(status: JsonField<Status>) = apply { body.status(status) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -499,25 +702,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PlanCreateParams =
             PlanCreateParams(
                 body.build(),
@@ -557,6 +741,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun newPlanUnitPrice(): Optional<NewPlanUnitPrice> = Optional.ofNullable(newPlanUnitPrice)
 
         fun newPlanPackagePrice(): Optional<NewPlanPackagePrice> =
@@ -780,6 +966,58 @@ constructor(
             }
         }
 
+        fun validate(): Price = apply {
+            if (!validated) {
+                if (
+                    newPlanUnitPrice == null &&
+                        newPlanPackagePrice == null &&
+                        newPlanMatrixPrice == null &&
+                        newPlanTieredPrice == null &&
+                        newPlanTieredBpsPrice == null &&
+                        newPlanBpsPrice == null &&
+                        newPlanBulkBpsPrice == null &&
+                        newPlanBulkPrice == null &&
+                        newPlanThresholdTotalAmountPrice == null &&
+                        newPlanTieredPackagePrice == null &&
+                        newPlanTieredWithMinimumPrice == null &&
+                        newPlanUnitWithPercentPrice == null &&
+                        newPlanPackageWithAllocationPrice == null &&
+                        newPlanTierWithProrationPrice == null &&
+                        newPlanUnitWithProrationPrice == null &&
+                        newPlanGroupedAllocationPrice == null &&
+                        newPlanGroupedWithProratedMinimumPrice == null &&
+                        newPlanGroupedWithMeteredMinimumPrice == null &&
+                        newPlanMatrixWithDisplayNamePrice == null &&
+                        newPlanBulkWithProrationPrice == null &&
+                        newPlanGroupedTieredPackagePrice == null
+                ) {
+                    throw OrbInvalidDataException("Unknown Price: $_json")
+                }
+                newPlanUnitPrice?.validate()
+                newPlanPackagePrice?.validate()
+                newPlanMatrixPrice?.validate()
+                newPlanTieredPrice?.validate()
+                newPlanTieredBpsPrice?.validate()
+                newPlanBpsPrice?.validate()
+                newPlanBulkBpsPrice?.validate()
+                newPlanBulkPrice?.validate()
+                newPlanThresholdTotalAmountPrice?.validate()
+                newPlanTieredPackagePrice?.validate()
+                newPlanTieredWithMinimumPrice?.validate()
+                newPlanUnitWithPercentPrice?.validate()
+                newPlanPackageWithAllocationPrice?.validate()
+                newPlanTierWithProrationPrice?.validate()
+                newPlanUnitWithProrationPrice?.validate()
+                newPlanGroupedAllocationPrice?.validate()
+                newPlanGroupedWithProratedMinimumPrice?.validate()
+                newPlanGroupedWithMeteredMinimumPrice?.validate()
+                newPlanMatrixWithDisplayNamePrice?.validate()
+                newPlanBulkWithProrationPrice?.validate()
+                newPlanGroupedTieredPackagePrice?.validate()
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
@@ -1017,92 +1255,130 @@ constructor(
 
                 when (modelType) {
                     "unit" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitPrice>())?.let {
-                            return Price(newPlanUnitPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitPrice>()) { it.validate() }
+                            ?.let {
+                                return Price(newPlanUnitPrice = it, _json = json)
+                            }
                     }
                     "package" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanPackagePrice>())?.let {
-                            return Price(newPlanPackagePrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanPackagePrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanPackagePrice = it, _json = json)
+                            }
                     }
                     "matrix" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanMatrixPrice>())?.let {
-                            return Price(newPlanMatrixPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanMatrixPrice>()) { it.validate() }
+                            ?.let {
+                                return Price(newPlanMatrixPrice = it, _json = json)
+                            }
                     }
                     "tiered" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredPrice>())?.let {
-                            return Price(newPlanTieredPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredPrice>()) { it.validate() }
+                            ?.let {
+                                return Price(newPlanTieredPrice = it, _json = json)
+                            }
                     }
                     "tiered_bps" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredBpsPrice>())?.let {
-                            return Price(newPlanTieredBpsPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredBpsPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanTieredBpsPrice = it, _json = json)
+                            }
                     }
                     "bps" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanBpsPrice>())?.let {
-                            return Price(newPlanBpsPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanBpsPrice>()) { it.validate() }
+                            ?.let {
+                                return Price(newPlanBpsPrice = it, _json = json)
+                            }
                     }
                     "bulk_bps" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkBpsPrice>())?.let {
-                            return Price(newPlanBulkBpsPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkBpsPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanBulkBpsPrice = it, _json = json)
+                            }
                     }
                     "bulk" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkPrice>())?.let {
-                            return Price(newPlanBulkPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkPrice>()) { it.validate() }
+                            ?.let {
+                                return Price(newPlanBulkPrice = it, _json = json)
+                            }
                     }
                     "threshold_total_amount" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanThresholdTotalAmountPrice>())
+                        tryDeserialize(node, jacksonTypeRef<NewPlanThresholdTotalAmountPrice>()) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(newPlanThresholdTotalAmountPrice = it, _json = json)
                             }
                     }
                     "tiered_package" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredPackagePrice>())?.let {
-                            return Price(newPlanTieredPackagePrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredPackagePrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanTieredPackagePrice = it, _json = json)
+                            }
                     }
                     "tiered_with_minimum" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredWithMinimumPrice>())?.let {
-                            return Price(newPlanTieredWithMinimumPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanTieredWithMinimumPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanTieredWithMinimumPrice = it, _json = json)
+                            }
                     }
                     "unit_with_percent" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitWithPercentPrice>())?.let {
-                            return Price(newPlanUnitWithPercentPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitWithPercentPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanUnitWithPercentPrice = it, _json = json)
+                            }
                     }
                     "package_with_allocation" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanPackageWithAllocationPrice>())
+                        tryDeserialize(node, jacksonTypeRef<NewPlanPackageWithAllocationPrice>()) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(newPlanPackageWithAllocationPrice = it, _json = json)
                             }
                     }
                     "tiered_with_proration" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanTierWithProrationPrice>())?.let {
-                            return Price(newPlanTierWithProrationPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanTierWithProrationPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanTierWithProrationPrice = it, _json = json)
+                            }
                     }
                     "unit_with_proration" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitWithProrationPrice>())?.let {
-                            return Price(newPlanUnitWithProrationPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanUnitWithProrationPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanUnitWithProrationPrice = it, _json = json)
+                            }
                     }
                     "grouped_allocation" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanGroupedAllocationPrice>())?.let {
-                            return Price(newPlanGroupedAllocationPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanGroupedAllocationPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanGroupedAllocationPrice = it, _json = json)
+                            }
                     }
                     "grouped_with_prorated_minimum" -> {
                         tryDeserialize(
                                 node,
                                 jacksonTypeRef<NewPlanGroupedWithProratedMinimumPrice>()
-                            )
+                            ) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(
                                     newPlanGroupedWithProratedMinimumPrice = it,
@@ -1114,7 +1390,9 @@ constructor(
                         tryDeserialize(
                                 node,
                                 jacksonTypeRef<NewPlanGroupedWithMeteredMinimumPrice>()
-                            )
+                            ) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(
                                     newPlanGroupedWithMeteredMinimumPrice = it,
@@ -1123,18 +1401,25 @@ constructor(
                             }
                     }
                     "matrix_with_display_name" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanMatrixWithDisplayNamePrice>())
+                        tryDeserialize(node, jacksonTypeRef<NewPlanMatrixWithDisplayNamePrice>()) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(newPlanMatrixWithDisplayNamePrice = it, _json = json)
                             }
                     }
                     "bulk_with_proration" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkWithProrationPrice>())?.let {
-                            return Price(newPlanBulkWithProrationPrice = it, _json = json)
-                        }
+                        tryDeserialize(node, jacksonTypeRef<NewPlanBulkWithProrationPrice>()) {
+                                it.validate()
+                            }
+                            ?.let {
+                                return Price(newPlanBulkWithProrationPrice = it, _json = json)
+                            }
                     }
                     "grouped_tiered_package" -> {
-                        tryDeserialize(node, jacksonTypeRef<NewPlanGroupedTieredPackagePrice>())
+                        tryDeserialize(node, jacksonTypeRef<NewPlanGroupedTieredPackagePrice>()) {
+                                it.validate()
+                            }
                             ?.let {
                                 return Price(newPlanGroupedTieredPackagePrice = it, _json = json)
                             }
@@ -1202,92 +1487,208 @@ constructor(
         class NewPlanUnitPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("unit_config")
+            @ExcludeMissing
+            private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+            @JsonProperty("unit_config")
+            @ExcludeMissing
+            fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1295,12 +1696,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanUnitPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    unitConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1310,21 +1735,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var unitConfig: UnitConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var unitConfig: JsonField<UnitConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1348,25 +1775,41 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
 
-                fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                    this.unitConfig = unitConfig
+                }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -1375,13 +1818,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -1398,13 +1848,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -1414,10 +1872,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -1428,11 +1893,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -1440,22 +1910,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -1472,22 +1951,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -1497,12 +1988,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -1511,6 +2010,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -1690,18 +2196,34 @@ constructor(
             class UnitConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("unit_amount") private val unitAmount: String,
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                private val unitAmount: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Rate per unit of usage */
-                @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                /** Rate per unit of usage */
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): UnitConfig = apply {
+                    if (!validated) {
+                        unitAmount()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1711,7 +2233,7 @@ constructor(
 
                 class Builder {
 
-                    private var unitAmount: String? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1721,7 +2243,12 @@ constructor(
                     }
 
                     /** Rate per unit of usage */
-                    fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                    fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                    /** Rate per unit of usage */
+                    fun unitAmount(unitAmount: JsonField<String>) = apply {
+                        this.unitAmount = unitAmount
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -1777,22 +2304,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1802,8 +2353,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1816,10 +2367,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -1939,22 +2497,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1964,8 +2546,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1978,10 +2560,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -2110,6 +2699,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2190,133 +2787,275 @@ constructor(
         class NewPlanPackagePrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("package_config") private val packageConfig: PackageConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("package_config")
+            @ExcludeMissing
+            private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+            fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
-            @JsonProperty("billing_cycle_configuration")
             fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
             /** An alias for the price. */
-            @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
             /** The property used to group this price on an invoice */
-            @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
-            @JsonProperty("invoicing_cycle_configuration")
             fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
-            @JsonAnyGetter
-            @ExcludeMissing
-            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-            fun toBuilder() = Builder().from(this)
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            companion object {
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
-                @JvmStatic fun builder() = Builder()
-            }
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            class Builder {
+            @JsonProperty("package_config")
+            @ExcludeMissing
+            fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var packageConfig: PackageConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
-                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
-                @JvmSynthetic
-                internal fun from(newPlanPackagePrice: NewPlanPackagePrice) = apply {
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+            /** An alias for the price. */
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+            /** The property used to group this price on an invoice */
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
+
+            @JsonAnyGetter
+            @ExcludeMissing
+            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanPackagePrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    packageConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
+            fun toBuilder() = Builder().from(this)
+
+            companion object {
+
+                @JvmStatic fun builder() = Builder()
+            }
+
+            class Builder {
+
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var packageConfig: JsonField<PackageConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
+                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+
+                @JvmSynthetic
+                internal fun from(newPlanPackagePrice: NewPlanPackagePrice) = apply {
                     cadence = newPlanPackagePrice.cadence
                     itemId = newPlanPackagePrice.itemId
                     modelType = newPlanPackagePrice.modelType
@@ -2336,17 +3075,33 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun packageConfig(packageConfig: PackageConfig) =
+                    packageConfig(JsonField.of(packageConfig))
 
-                fun packageConfig(packageConfig: PackageConfig) = apply {
+                fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                     this.packageConfig = packageConfig
                 }
 
@@ -2354,9 +3109,8 @@ constructor(
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -2365,13 +3119,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -2388,13 +3149,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -2404,10 +3173,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -2418,11 +3194,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -2430,22 +3211,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -2462,22 +3252,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -2487,12 +3289,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -2501,6 +3311,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -2682,25 +3499,52 @@ constructor(
             class PackageConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("package_amount") private val packageAmount: String,
-                @JsonProperty("package_size") private val packageSize: Long,
+                @JsonProperty("package_amount")
+                @ExcludeMissing
+                private val packageAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_size")
+                @ExcludeMissing
+                private val packageSize: JsonField<Long> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** A currency amount to rate usage by */
-                @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+                /**
+                 * An integer amount to represent package size. For example, 1000 here would divide
+                 * usage by 1000 before multiplying by package_amount in rating
+                 */
+                fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                /** A currency amount to rate usage by */
+                @JsonProperty("package_amount")
+                @ExcludeMissing
+                fun _packageAmount(): JsonField<String> = packageAmount
 
                 /**
                  * An integer amount to represent package size. For example, 1000 here would divide
                  * usage by 1000 before multiplying by package_amount in rating
                  */
-                @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                @JsonProperty("package_size")
+                @ExcludeMissing
+                fun _packageSize(): JsonField<Long> = packageSize
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): PackageConfig = apply {
+                    if (!validated) {
+                        packageAmount()
+                        packageSize()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2710,8 +3554,8 @@ constructor(
 
                 class Builder {
 
-                    private var packageAmount: String? = null
-                    private var packageSize: Long? = null
+                    private var packageAmount: JsonField<String>? = null
+                    private var packageSize: JsonField<Long>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2722,7 +3566,11 @@ constructor(
                     }
 
                     /** A currency amount to rate usage by */
-                    fun packageAmount(packageAmount: String) = apply {
+                    fun packageAmount(packageAmount: String) =
+                        packageAmount(JsonField.of(packageAmount))
+
+                    /** A currency amount to rate usage by */
+                    fun packageAmount(packageAmount: JsonField<String>) = apply {
                         this.packageAmount = packageAmount
                     }
 
@@ -2730,7 +3578,15 @@ constructor(
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    fun packageSize(packageSize: Long) = apply { this.packageSize = packageSize }
+                    fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    fun packageSize(packageSize: JsonField<Long>) = apply {
+                        this.packageSize = packageSize
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2791,22 +3647,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2816,8 +3696,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2830,10 +3710,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -2953,22 +3840,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2978,8 +3889,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -2992,10 +3903,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -3124,6 +4042,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -3204,129 +4130,271 @@ constructor(
         class NewPlanMatrixPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("matrix_config")
+            @ExcludeMissing
+            private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+            fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
-            @JsonProperty("billing_cycle_configuration")
             fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
             /** An alias for the price. */
-            @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
             /** The property used to group this price on an invoice */
-            @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
-            @JsonProperty("invoicing_cycle_configuration")
             fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
-            @JsonAnyGetter
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+            @JsonProperty("matrix_config")
             @ExcludeMissing
-            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+            fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-            fun toBuilder() = Builder().from(this)
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
-            companion object {
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+            /** An alias for the price. */
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+            /** The property used to group this price on an invoice */
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
+
+            @JsonAnyGetter
+            @ExcludeMissing
+            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanMatrixPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    matrixConfig().validate()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
+            fun toBuilder() = Builder().from(this)
+
+            companion object {
 
                 @JvmStatic fun builder() = Builder()
             }
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var matrixConfig: MatrixConfig? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var matrixConfig: JsonField<MatrixConfig>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3350,27 +4418,42 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                fun matrixConfig(matrixConfig: MatrixConfig) =
+                    matrixConfig(JsonField.of(matrixConfig))
+
+                fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                     this.matrixConfig = matrixConfig
                 }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -3379,13 +4462,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -3402,13 +4492,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -3418,10 +4516,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -3432,11 +4537,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -3444,22 +4554,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -3476,22 +4595,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -3501,12 +4632,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -3515,6 +4654,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -3643,29 +4789,63 @@ constructor(
             class MatrixConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                @JsonProperty("dimensions") private val dimensions: List<String?>,
-                @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                @JsonProperty("default_unit_amount")
+                @ExcludeMissing
+                private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("dimensions")
+                @ExcludeMissing
+                private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                @JsonProperty("matrix_values")
+                @ExcludeMissing
+                private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                /**
+                 * Default per unit rate for any usage not bucketed into a specified matrix_value
+                 */
+                fun defaultUnitAmount(): String =
+                    defaultUnitAmount.getRequired("default_unit_amount")
+
+                /** One or two event property values to evaluate matrix groups by */
+                fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                /** Matrix values for specified matrix grouping keys */
+                fun matrixValues(): List<MatrixValue> = matrixValues.getRequired("matrix_values")
+
                 /**
                  * Default per unit rate for any usage not bucketed into a specified matrix_value
                  */
                 @JsonProperty("default_unit_amount")
-                fun defaultUnitAmount(): String = defaultUnitAmount
+                @ExcludeMissing
+                fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                 /** One or two event property values to evaluate matrix groups by */
-                @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                @JsonProperty("dimensions")
+                @ExcludeMissing
+                fun _dimensions(): JsonField<List<String?>> = dimensions
 
                 /** Matrix values for specified matrix grouping keys */
-                @JsonProperty("matrix_values") fun matrixValues(): List<MatrixValue> = matrixValues
+                @JsonProperty("matrix_values")
+                @ExcludeMissing
+                fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): MatrixConfig = apply {
+                    if (!validated) {
+                        defaultUnitAmount()
+                        dimensions()
+                        matrixValues().forEach { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -3675,16 +4855,16 @@ constructor(
 
                 class Builder {
 
-                    private var defaultUnitAmount: String? = null
-                    private var dimensions: MutableList<String?>? = null
-                    private var matrixValues: MutableList<MatrixValue>? = null
+                    private var defaultUnitAmount: JsonField<String>? = null
+                    private var dimensions: JsonField<MutableList<String?>>? = null
+                    private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixConfig: MatrixConfig) = apply {
                         defaultUnitAmount = matrixConfig.defaultUnitAmount
-                        dimensions = matrixConfig.dimensions.toMutableList()
-                        matrixValues = matrixConfig.matrixValues.toMutableList()
+                        dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                        matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                         additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                     }
 
@@ -3692,28 +4872,60 @@ constructor(
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
-                    fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                    fun defaultUnitAmount(defaultUnitAmount: String) =
+                        defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                         this.defaultUnitAmount = defaultUnitAmount
                     }
 
                     /** One or two event property values to evaluate matrix groups by */
-                    fun dimensions(dimensions: List<String?>) = apply {
-                        this.dimensions = dimensions.toMutableList()
+                    fun dimensions(dimensions: List<String?>) = dimensions(JsonField.of(dimensions))
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                        this.dimensions = dimensions.map { it.toMutableList() }
                     }
 
                     /** One or two event property values to evaluate matrix groups by */
                     fun addDimension(dimension: String) = apply {
-                        dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                        dimensions =
+                            (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimension)
+                            }
                     }
 
                     /** Matrix values for specified matrix grouping keys */
-                    fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                        this.matrixValues = matrixValues.toMutableList()
+                    fun matrixValues(matrixValues: List<MatrixValue>) =
+                        matrixValues(JsonField.of(matrixValues))
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                        this.matrixValues = matrixValues.map { it.toMutableList() }
                     }
 
                     /** Matrix values for specified matrix grouping keys */
                     fun addMatrixValue(matrixValue: MatrixValue) = apply {
-                        matrixValues = (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                        matrixValues =
+                            (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(matrixValue)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -3744,11 +4956,11 @@ constructor(
                                 "`defaultUnitAmount` is required but was not set"
                             },
                             checkNotNull(dimensions) { "`dimensions` is required but was not set" }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(matrixValues) {
                                     "`matrixValues` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -3757,27 +4969,55 @@ constructor(
                 class MatrixValue
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("dimension_values") private val dimensionValues: List<String?>,
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("dimension_values")
+                    @ExcludeMissing
+                    private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * One or two matrix keys to filter usage to this Matrix value by. For example,
+                     * ["region", "tier"] could be used to filter cloud usage by a cloud region and
+                     * an instance tier.
+                     */
+                    fun dimensionValues(): List<String?> =
+                        dimensionValues.getRequired("dimension_values")
+
+                    /** Unit price for the specified dimension_values */
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                     /**
                      * One or two matrix keys to filter usage to this Matrix value by. For example,
                      * ["region", "tier"] could be used to filter cloud usage by a cloud region and
                      * an instance tier.
                      */
                     @JsonProperty("dimension_values")
-                    fun dimensionValues(): List<String?> = dimensionValues
+                    @ExcludeMissing
+                    fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                     /** Unit price for the specified dimension_values */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixValue = apply {
+                        if (!validated) {
+                            dimensionValues()
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -3787,14 +5027,14 @@ constructor(
 
                     class Builder {
 
-                        private var dimensionValues: MutableList<String?>? = null
-                        private var unitAmount: String? = null
+                        private var dimensionValues: JsonField<MutableList<String?>>? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixValue: MatrixValue) = apply {
-                            dimensionValues = matrixValue.dimensionValues.toMutableList()
+                            dimensionValues = matrixValue.dimensionValues.map { it.toMutableList() }
                             unitAmount = matrixValue.unitAmount
                             additionalProperties = matrixValue.additionalProperties.toMutableMap()
                         }
@@ -3804,8 +5044,16 @@ constructor(
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
-                        fun dimensionValues(dimensionValues: List<String?>) = apply {
-                            this.dimensionValues = dimensionValues.toMutableList()
+                        fun dimensionValues(dimensionValues: List<String?>) =
+                            dimensionValues(JsonField.of(dimensionValues))
+
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                            this.dimensionValues = dimensionValues.map { it.toMutableList() }
                         }
 
                         /**
@@ -3815,11 +5063,24 @@ constructor(
                          */
                         fun addDimensionValue(dimensionValue: String) = apply {
                             dimensionValues =
-                                (dimensionValues ?: mutableListOf()).apply { add(dimensionValue) }
+                                (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimensionValue)
+                                }
                         }
 
                         /** Unit price for the specified dimension_values */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -3848,7 +5109,7 @@ constructor(
                                 checkNotNull(dimensionValues) {
                                         "`dimensionValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(unitAmount) {
                                     "`unitAmount` is required but was not set"
                                 },
@@ -3950,22 +5211,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -3975,8 +5260,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -3989,10 +5274,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -4112,22 +5404,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4137,8 +5453,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -4151,10 +5467,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -4283,6 +5606,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4363,92 +5694,208 @@ constructor(
         class NewPlanTieredPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("tiered_config")
+            @ExcludeMissing
+            private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+            @JsonProperty("tiered_config")
+            @ExcludeMissing
+            fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -4456,12 +5903,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanTieredPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    tieredConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -4471,21 +5942,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var tieredConfig: TieredConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var tieredConfig: JsonField<TieredConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4509,17 +5982,33 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun tieredConfig(tieredConfig: TieredConfig) =
+                    tieredConfig(JsonField.of(tieredConfig))
 
-                fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                     this.tieredConfig = tieredConfig
                 }
 
@@ -4527,9 +6016,8 @@ constructor(
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -4538,13 +6026,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -4561,13 +6056,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -4577,10 +6080,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -4591,11 +6101,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -4603,22 +6118,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -4635,22 +6159,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -4660,12 +6196,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -4674,6 +6218,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -4853,18 +6404,32 @@ constructor(
             class TieredConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("tiers") private val tiers: List<Tier>,
+                @JsonProperty("tiers")
+                @ExcludeMissing
+                private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Tiers for rating based on total usage quantities into the specified tier */
-                @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                /** Tiers for rating based on total usage quantities into the specified tier */
+                @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): TieredConfig = apply {
+                    if (!validated) {
+                        tiers().forEach { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4874,21 +6439,35 @@ constructor(
 
                 class Builder {
 
-                    private var tiers: MutableList<Tier>? = null
+                    private var tiers: JsonField<MutableList<Tier>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(tieredConfig: TieredConfig) = apply {
-                        tiers = tieredConfig.tiers.toMutableList()
+                        tiers = tieredConfig.tiers.map { it.toMutableList() }
                         additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                     }
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                    fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                        this.tiers = tiers.map { it.toMutableList() }
+                    }
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
                     fun addTier(tier: Tier) = apply {
-                        tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                        tiers =
+                            (tiers ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(tier)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -4916,7 +6495,7 @@ constructor(
                     fun build(): TieredConfig =
                         TieredConfig(
                             checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable()
                         )
                 }
@@ -4925,27 +6504,59 @@ constructor(
                 class Tier
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("first_unit") private val firstUnit: Double,
-                    @JsonProperty("unit_amount") private val unitAmount: String,
-                    @JsonProperty("last_unit") private val lastUnit: Double?,
+                    @JsonProperty("first_unit")
+                    @ExcludeMissing
+                    private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("last_unit")
+                    @ExcludeMissing
+                    private val lastUnit: JsonField<Double> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Inclusive tier starting value */
-                    @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                    fun firstUnit(): Double = firstUnit.getRequired("first_unit")
+
+                    /** Amount per unit */
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Exclusive tier ending value. If null, this is treated as the last tier */
+                    fun lastUnit(): Optional<Double> =
+                        Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                    /** Inclusive tier starting value */
+                    @JsonProperty("first_unit")
+                    @ExcludeMissing
+                    fun _firstUnit(): JsonField<Double> = firstUnit
 
                     /** Amount per unit */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     /** Exclusive tier ending value. If null, this is treated as the last tier */
                     @JsonProperty("last_unit")
-                    fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                    @ExcludeMissing
+                    fun _lastUnit(): JsonField<Double> = lastUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Tier = apply {
+                        if (!validated) {
+                            firstUnit()
+                            unitAmount()
+                            lastUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4955,9 +6566,9 @@ constructor(
 
                     class Builder {
 
-                        private var firstUnit: Double? = null
-                        private var unitAmount: String? = null
-                        private var lastUnit: Double? = null
+                        private var firstUnit: JsonField<Double>? = null
+                        private var unitAmount: JsonField<String>? = null
+                        private var lastUnit: JsonField<Double> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4970,15 +6581,25 @@ constructor(
                         }
 
                         /** Inclusive tier starting value */
-                        fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                        fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                        /** Inclusive tier starting value */
+                        fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                            this.firstUnit = firstUnit
+                        }
+
+                        /** Amount per unit */
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
 
                         /** Amount per unit */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
-                        fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                        fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
@@ -4994,6 +6615,13 @@ constructor(
                         fun lastUnit(lastUnit: Optional<Double>) =
                             lastUnit(lastUnit.orElse(null) as Double?)
 
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                            this.lastUnit = lastUnit
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -5072,22 +6700,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5097,8 +6749,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5111,10 +6763,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -5234,22 +6893,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5259,8 +6942,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5273,10 +6956,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -5405,6 +7095,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5485,93 +7183,209 @@ constructor(
         class NewPlanTieredBpsPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("tiered_bps_config")
+            @ExcludeMissing
+            private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            fun tieredBpsConfig(): TieredBpsConfig =
+                tieredBpsConfig.getRequired("tiered_bps_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonProperty("tiered_bps_config")
-            fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+            @ExcludeMissing
+            fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -5579,12 +7393,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanTieredBpsPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    tieredBpsConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -5594,21 +7432,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var tieredBpsConfig: TieredBpsConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5632,17 +7472,33 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: String) = name(JsonField.of(name))
 
-                fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                /** The name of the price. */
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                    tieredBpsConfig(JsonField.of(tieredBpsConfig))
+
+                fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                     this.tieredBpsConfig = tieredBpsConfig
                 }
 
@@ -5650,9 +7506,8 @@ constructor(
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -5661,13 +7516,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -5684,13 +7546,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -5700,10 +7570,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -5714,11 +7591,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -5726,22 +7608,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -5758,22 +7649,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -5783,12 +7686,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -5797,6 +7708,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -5978,7 +7896,9 @@ constructor(
             class TieredBpsConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("tiers") private val tiers: List<Tier>,
+                @JsonProperty("tiers")
+                @ExcludeMissing
+                private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
@@ -5987,12 +7907,27 @@ constructor(
                  * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
                  * tiers
                  */
-                @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                /**
+                 * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
+                 * tiers
+                 */
+                @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): TieredBpsConfig = apply {
+                    if (!validated) {
+                        tiers().forEach { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6002,12 +7937,12 @@ constructor(
 
                 class Builder {
 
-                    private var tiers: MutableList<Tier>? = null
+                    private var tiers: JsonField<MutableList<Tier>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                        tiers = tieredBpsConfig.tiers.toMutableList()
+                        tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                         additionalProperties = tieredBpsConfig.additionalProperties.toMutableMap()
                     }
 
@@ -6015,14 +7950,31 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                    fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                        this.tiers = tiers.map { it.toMutableList() }
+                    }
 
                     /**
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
                     fun addTier(tier: Tier) = apply {
-                        tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                        tiers =
+                            (tiers ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(tier)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -6050,7 +8002,7 @@ constructor(
                     fun build(): TieredBpsConfig =
                         TieredBpsConfig(
                             checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable()
                         )
                 }
@@ -6059,32 +8011,70 @@ constructor(
                 class Tier
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("minimum_amount") private val minimumAmount: String,
-                    @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("minimum_amount")
+                    @ExcludeMissing
+                    private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("maximum_amount")
+                    @ExcludeMissing
+                    private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Per-event basis point rate */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Inclusive tier starting value */
+                    fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                    /** Exclusive tier ending value */
+                    fun maximumAmount(): Optional<String> =
+                        Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                    /** Per unit maximum to charge */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Per-event basis point rate */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Inclusive tier starting value */
-                    @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                    @JsonProperty("minimum_amount")
+                    @ExcludeMissing
+                    fun _minimumAmount(): JsonField<String> = minimumAmount
 
                     /** Exclusive tier ending value */
                     @JsonProperty("maximum_amount")
-                    fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                    @ExcludeMissing
+                    fun _maximumAmount(): JsonField<String> = maximumAmount
 
                     /** Per unit maximum to charge */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Tier = apply {
+                        if (!validated) {
+                            bps()
+                            minimumAmount()
+                            maximumAmount()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6094,10 +8084,10 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var minimumAmount: String? = null
-                        private var maximumAmount: String? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var minimumAmount: JsonField<String>? = null
+                        private var maximumAmount: JsonField<String> = JsonMissing.of()
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6111,31 +8101,46 @@ constructor(
                         }
 
                         /** Per-event basis point rate */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Per-event basis point rate */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Inclusive tier starting value */
-                        fun minimumAmount(minimumAmount: String) = apply {
+                        fun minimumAmount(minimumAmount: String) =
+                            minimumAmount(JsonField.of(minimumAmount))
+
+                        /** Inclusive tier starting value */
+                        fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                             this.minimumAmount = minimumAmount
                         }
 
                         /** Exclusive tier ending value */
-                        fun maximumAmount(maximumAmount: String?) = apply {
-                            this.maximumAmount = maximumAmount
-                        }
+                        fun maximumAmount(maximumAmount: String?) =
+                            maximumAmount(JsonField.ofNullable(maximumAmount))
 
                         /** Exclusive tier ending value */
                         fun maximumAmount(maximumAmount: Optional<String>) =
                             maximumAmount(maximumAmount.orElse(null))
 
-                        /** Per unit maximum to charge */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                            this.maximumAmount = maximumAmount
                         }
 
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                         /** Per unit maximum to charge */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -6213,22 +8218,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6238,8 +8267,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6252,10 +8281,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -6375,22 +8411,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6400,8 +8460,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6414,10 +8474,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -6546,9 +8613,17 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
-                fun toBuilder() = Builder().from(this)
+                private var validated: Boolean = false
 
-                companion object {
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
+                fun toBuilder() = Builder().from(this)
+
+                companion object {
 
                     @JvmStatic fun builder() = Builder()
                 }
@@ -6626,92 +8701,208 @@ constructor(
         class NewPlanBpsPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("bps_config")
+            @ExcludeMissing
+            private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+            fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            @JsonProperty("bps_config")
+            @ExcludeMissing
+            fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -6719,12 +8910,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanBpsPrice = apply {
+                if (!validated) {
+                    bpsConfig().validate()
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -6734,21 +8949,23 @@ constructor(
 
             class Builder {
 
-                private var bpsConfig: BpsConfig? = null
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var bpsConfig: JsonField<BpsConfig>? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -6771,26 +8988,42 @@ constructor(
                     additionalProperties = newPlanBpsPrice.additionalProperties.toMutableMap()
                 }
 
-                fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                    this.bpsConfig = bpsConfig
+                }
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -6799,13 +9032,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -6822,13 +9062,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -6838,10 +9086,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -6852,11 +9107,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -6864,22 +9124,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -6896,22 +9165,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -6921,12 +9202,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -6935,6 +9224,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -6982,23 +9278,45 @@ constructor(
             class BpsConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("bps") private val bps: Double,
-                @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                @JsonProperty("bps")
+                @ExcludeMissing
+                private val bps: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("per_unit_maximum")
+                @ExcludeMissing
+                private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Basis point take rate per event */
-                @JsonProperty("bps") fun bps(): Double = bps
+                fun bps(): Double = bps.getRequired("bps")
+
+                /** Optional currency amount maximum to cap spend per event */
+                fun perUnitMaximum(): Optional<String> =
+                    Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                /** Basis point take rate per event */
+                @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                 /** Optional currency amount maximum to cap spend per event */
                 @JsonProperty("per_unit_maximum")
-                fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                @ExcludeMissing
+                fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BpsConfig = apply {
+                    if (!validated) {
+                        bps()
+                        perUnitMaximum()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7008,8 +9326,8 @@ constructor(
 
                 class Builder {
 
-                    private var bps: Double? = null
-                    private var perUnitMaximum: String? = null
+                    private var bps: JsonField<Double>? = null
+                    private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7020,17 +9338,24 @@ constructor(
                     }
 
                     /** Basis point take rate per event */
-                    fun bps(bps: Double) = apply { this.bps = bps }
+                    fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                    /** Basis point take rate per event */
+                    fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                     /** Optional currency amount maximum to cap spend per event */
-                    fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                        this.perUnitMaximum = perUnitMaximum
-                    }
+                    fun perUnitMaximum(perUnitMaximum: String?) =
+                        perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                     /** Optional currency amount maximum to cap spend per event */
                     fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                         perUnitMaximum(perUnitMaximum.orElse(null))
 
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                        this.perUnitMaximum = perUnitMaximum
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -7218,22 +9543,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7243,8 +9592,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7257,10 +9606,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -7380,22 +9736,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7405,8 +9785,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7419,10 +9799,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -7551,6 +9938,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7631,92 +10026,208 @@ constructor(
         class NewPlanBulkBpsPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("bulk_bps_config")
+            @ExcludeMissing
+            private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+            fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            @JsonProperty("bulk_bps_config")
+            @ExcludeMissing
+            fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -7724,12 +10235,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanBulkBpsPrice = apply {
+                if (!validated) {
+                    bulkBpsConfig().validate()
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -7739,21 +10274,23 @@ constructor(
 
             class Builder {
 
-                private var bulkBpsConfig: BulkBpsConfig? = null
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7776,28 +10313,43 @@ constructor(
                     additionalProperties = newPlanBulkBpsPrice.additionalProperties.toMutableMap()
                 }
 
-                fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                    bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                     this.bulkBpsConfig = bulkBpsConfig
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -7806,13 +10358,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -7829,13 +10388,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -7845,10 +10412,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -7859,11 +10433,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -7871,22 +10450,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -7903,22 +10491,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -7928,12 +10528,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -7942,6 +10550,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -7991,7 +10606,9 @@ constructor(
             class BulkBpsConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("tiers") private val tiers: List<Tier>,
+                @JsonProperty("tiers")
+                @ExcludeMissing
+                private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
@@ -8000,12 +10617,27 @@ constructor(
                  * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
                  * based on total volume
                  */
-                @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                /**
+                 * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
+                 * based on total volume
+                 */
+                @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BulkBpsConfig = apply {
+                    if (!validated) {
+                        tiers().forEach { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -8015,12 +10647,12 @@ constructor(
 
                 class Builder {
 
-                    private var tiers: MutableList<Tier>? = null
+                    private var tiers: JsonField<MutableList<Tier>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                        tiers = bulkBpsConfig.tiers.toMutableList()
+                        tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                         additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                     }
 
@@ -8028,14 +10660,31 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                    fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                        this.tiers = tiers.map { it.toMutableList() }
+                    }
 
                     /**
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
                     fun addTier(tier: Tier) = apply {
-                        tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                        tiers =
+                            (tiers ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(tier)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -8063,7 +10712,7 @@ constructor(
                     fun build(): BulkBpsConfig =
                         BulkBpsConfig(
                             checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable()
                         )
                 }
@@ -8072,28 +10721,58 @@ constructor(
                 class Tier
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("maximum_amount")
+                    @ExcludeMissing
+                    private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis points to rate on */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Upper bound for tier */
+                    fun maximumAmount(): Optional<String> =
+                        Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                    /** The maximum amount to charge for any one event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis points to rate on */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Upper bound for tier */
                     @JsonProperty("maximum_amount")
-                    fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                    @ExcludeMissing
+                    fun _maximumAmount(): JsonField<String> = maximumAmount
 
                     /** The maximum amount to charge for any one event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Tier = apply {
+                        if (!validated) {
+                            bps()
+                            maximumAmount()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8103,9 +10782,9 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var maximumAmount: String? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var maximumAmount: JsonField<String> = JsonMissing.of()
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8118,26 +10797,37 @@ constructor(
                         }
 
                         /** Basis points to rate on */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis points to rate on */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Upper bound for tier */
-                        fun maximumAmount(maximumAmount: String?) = apply {
-                            this.maximumAmount = maximumAmount
-                        }
+                        fun maximumAmount(maximumAmount: String?) =
+                            maximumAmount(JsonField.ofNullable(maximumAmount))
 
                         /** Upper bound for tier */
                         fun maximumAmount(maximumAmount: Optional<String>) =
                             maximumAmount(maximumAmount.orElse(null))
 
-                        /** The maximum amount to charge for any one event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
+                        /** Upper bound for tier */
+                        fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                            this.maximumAmount = maximumAmount
                         }
 
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                         /** The maximum amount to charge for any one event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -8344,22 +11034,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -8369,8 +11083,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -8383,10 +11097,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -8506,22 +11227,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -8531,8 +11276,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -8545,10 +11290,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -8677,6 +11429,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -8757,92 +11517,208 @@ constructor(
         class NewPlanBulkPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @JsonProperty("bulk_config")
+            @ExcludeMissing
+            private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
-
-            @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
-
-            /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
-
-            /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            @JsonProperty("bulk_config")
+            @ExcludeMissing
+            fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -8850,12 +11726,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanBulkPrice = apply {
+                if (!validated) {
+                    bulkConfig().validate()
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8865,21 +11765,23 @@ constructor(
 
             class Builder {
 
-                private var bulkConfig: BulkConfig? = null
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var bulkConfig: JsonField<BulkConfig>? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -8902,26 +11804,42 @@ constructor(
                     additionalProperties = newPlanBulkPrice.additionalProperties.toMutableMap()
                 }
 
-                fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                    this.bulkConfig = bulkConfig
+                }
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -8930,13 +11848,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -8953,13 +11878,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -8969,10 +11902,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -8983,11 +11923,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -8995,22 +11940,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -9027,22 +11981,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -9052,12 +12018,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -9066,6 +12040,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -9113,18 +12094,32 @@ constructor(
             class BulkConfig
             @JsonCreator
             private constructor(
-                @JsonProperty("tiers") private val tiers: List<Tier>,
+                @JsonProperty("tiers")
+                @ExcludeMissing
+                private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Bulk tiers for rating based on total usage volume */
-                @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                /** Bulk tiers for rating based on total usage volume */
+                @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BulkConfig = apply {
+                    if (!validated) {
+                        tiers().forEach { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9134,21 +12129,35 @@ constructor(
 
                 class Builder {
 
-                    private var tiers: MutableList<Tier>? = null
+                    private var tiers: JsonField<MutableList<Tier>>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(bulkConfig: BulkConfig) = apply {
-                        tiers = bulkConfig.tiers.toMutableList()
+                        tiers = bulkConfig.tiers.map { it.toMutableList() }
                         additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                     }
 
                     /** Bulk tiers for rating based on total usage volume */
-                    fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                    fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                        this.tiers = tiers.map { it.toMutableList() }
+                    }
 
                     /** Bulk tiers for rating based on total usage volume */
                     fun addTier(tier: Tier) = apply {
-                        tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                        tiers =
+                            (tiers ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(tier)
+                            }
                     }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -9176,7 +12185,7 @@ constructor(
                     fun build(): BulkConfig =
                         BulkConfig(
                             checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             additionalProperties.toImmutable()
                         )
                 }
@@ -9185,23 +12194,47 @@ constructor(
                 class Tier
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
-                    @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("maximum_units")
+                    @ExcludeMissing
+                    private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Amount per unit */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Upper bound for this tier */
+                    fun maximumUnits(): Optional<Double> =
+                        Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                    /** Amount per unit */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     /** Upper bound for this tier */
                     @JsonProperty("maximum_units")
-                    fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                    @ExcludeMissing
+                    fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Tier = apply {
+                        if (!validated) {
+                            unitAmount()
+                            maximumUnits()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9211,8 +12244,8 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
-                        private var maximumUnits: Double? = null
+                        private var unitAmount: JsonField<String>? = null
+                        private var maximumUnits: JsonField<Double> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9224,13 +12257,17 @@ constructor(
                         }
 
                         /** Amount per unit */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
 
-                        /** Upper bound for this tier */
-                        fun maximumUnits(maximumUnits: Double?) = apply {
-                            this.maximumUnits = maximumUnits
+                        /** Amount per unit */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
                         }
 
+                        /** Upper bound for this tier */
+                        fun maximumUnits(maximumUnits: Double?) =
+                            maximumUnits(JsonField.ofNullable(maximumUnits))
+
                         /** Upper bound for this tier */
                         fun maximumUnits(maximumUnits: Double) =
                             maximumUnits(maximumUnits as Double?)
@@ -9242,6 +12279,11 @@ constructor(
                         fun maximumUnits(maximumUnits: Optional<Double>) =
                             maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                        /** Upper bound for this tier */
+                        fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                            this.maximumUnits = maximumUnits
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -9449,22 +12491,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9474,8 +12540,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9488,10 +12554,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -9611,22 +12684,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9636,8 +12733,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9650,10 +12747,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -9782,6 +12886,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9862,95 +12974,211 @@ constructor(
         class NewPlanThresholdTotalAmountPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
             @JsonProperty("threshold_total_amount_config")
-            private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("threshold_total_amount_config")
             fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
+
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+            @JsonProperty("threshold_total_amount_config")
+            @ExcludeMissing
+            fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                 thresholdTotalAmountConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -9958,12 +13186,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanThresholdTotalAmountPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    thresholdTotalAmountConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -9973,21 +13225,24 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                    null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -10017,27 +13272,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 fun thresholdTotalAmountConfig(
                     thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                fun thresholdTotalAmountConfig(
+                    thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                 ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -10046,13 +13317,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -10069,13 +13347,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -10085,10 +13371,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -10099,11 +13392,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -10111,22 +13409,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -10143,22 +13450,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -10168,12 +13487,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -10182,6 +13509,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -10371,6 +13705,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): ThresholdTotalAmountConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10440,22 +13782,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10465,8 +13831,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10479,10 +13845,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -10602,22 +13975,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10627,8 +14024,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10641,10 +14038,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -10773,6 +14177,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10853,131 +14265,272 @@ constructor(
         class NewPlanTieredPackagePrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
             @JsonProperty("tiered_package_config")
-            private val tieredPackageConfig: TieredPackageConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("tiered_package_config")
-            fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+            fun tieredPackageConfig(): TieredPackageConfig =
+                tieredPackageConfig.getRequired("tiered_package_config")
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
-            @JsonProperty("billing_cycle_configuration")
             fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
             /** An alias for the price. */
-            @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
             /** The property used to group this price on an invoice */
-            @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
-            @JsonProperty("invoicing_cycle_configuration")
             fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
-            @JsonAnyGetter
-            @ExcludeMissing
-            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-            fun toBuilder() = Builder().from(this)
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            companion object {
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
-                @JvmStatic fun builder() = Builder()
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+            @JsonProperty("tiered_package_config")
+            @ExcludeMissing
+            fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+            /** An alias for the price. */
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+            /** The property used to group this price on an invoice */
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
+
+            @JsonAnyGetter
+            @ExcludeMissing
+            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanTieredPackagePrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    tieredPackageConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
+            fun toBuilder() = Builder().from(this)
+
+            companion object {
+
+                @JvmStatic fun builder() = Builder()
             }
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var tieredPackageConfig: TieredPackageConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11003,27 +14556,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                    this.tieredPackageConfig = tieredPackageConfig
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
                 }
 
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
+
+                /** The name of the price. */
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                    tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                    apply {
+                        this.tieredPackageConfig = tieredPackageConfig
+                    }
+
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -11032,13 +14601,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -11055,13 +14631,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -11071,10 +14655,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -11085,11 +14676,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -11097,22 +14693,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -11129,22 +14734,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -11154,12 +14771,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -11168,6 +14793,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -11357,6 +14989,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): TieredPackageConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11425,22 +15065,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11450,8 +15114,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -11464,10 +15128,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -11587,22 +15258,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11612,8 +15307,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -11626,10 +15321,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -11758,6 +15460,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11838,135 +15548,278 @@ constructor(
         class NewPlanTieredWithMinimumPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
             @JsonProperty("tiered_with_minimum_config")
-            private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("tiered_with_minimum_config")
-            fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+            fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
-            @JsonProperty("billing_cycle_configuration")
             fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
             /** An alias for the price. */
-            @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
             /** The property used to group this price on an invoice */
-            @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
-            @JsonProperty("invoicing_cycle_configuration")
             fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
-            @JsonAnyGetter
-            @ExcludeMissing
-            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-            fun toBuilder() = Builder().from(this)
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            companion object {
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
-                @JvmStatic fun builder() = Builder()
-            }
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            class Builder {
+            @JsonProperty("tiered_with_minimum_config")
+            @ExcludeMissing
+            fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                tieredWithMinimumConfig
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
-                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
-                @JvmSynthetic
-                internal fun from(newPlanTieredWithMinimumPrice: NewPlanTieredWithMinimumPrice) =
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+            /** An alias for the price. */
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+            /** The property used to group this price on an invoice */
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
+
+            @JsonAnyGetter
+            @ExcludeMissing
+            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanTieredWithMinimumPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    tieredWithMinimumConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
+            fun toBuilder() = Builder().from(this)
+
+            companion object {
+
+                @JvmStatic fun builder() = Builder()
+            }
+
+            class Builder {
+
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
+                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+
+                @JvmSynthetic
+                internal fun from(newPlanTieredWithMinimumPrice: NewPlanTieredWithMinimumPrice) =
                     apply {
                         cadence = newPlanTieredWithMinimumPrice.cadence
                         itemId = newPlanTieredWithMinimumPrice.itemId
@@ -11991,28 +15844,42 @@ constructor(
                     }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                    apply {
-                        this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                    }
+                    tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                fun tieredWithMinimumConfig(
+                    tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -12021,13 +15888,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -12044,13 +15918,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -12060,10 +15942,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -12074,11 +15963,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -12086,22 +15980,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -12118,22 +16021,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -12143,12 +16058,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -12157,6 +16080,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -12346,6 +16276,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): TieredWithMinimumConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12414,22 +16352,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12439,8 +16401,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -12453,10 +16415,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -12576,22 +16545,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12601,8 +16594,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -12615,10 +16608,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -12747,6 +16747,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12827,139 +16835,280 @@ constructor(
         class NewPlanUnitWithPercentPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
             @JsonProperty("unit_with_percent_config")
-            private val unitWithPercentConfig: UnitWithPercentConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("unit_with_percent_config")
-            fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+            fun unitWithPercentConfig(): UnitWithPercentConfig =
+                unitWithPercentConfig.getRequired("unit_with_percent_config")
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
-            @JsonProperty("billing_cycle_configuration")
             fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
             /** An alias for the price. */
-            @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
             /** The property used to group this price on an invoice */
-            @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
-            @JsonProperty("invoicing_cycle_configuration")
             fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
-            @JsonAnyGetter
-            @ExcludeMissing
-            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-            fun toBuilder() = Builder().from(this)
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            companion object {
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
-                @JvmStatic fun builder() = Builder()
-            }
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            class Builder {
+            @JsonProperty("unit_with_percent_config")
+            @ExcludeMissing
+            fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> = unitWithPercentConfig
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
-                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
-                @JvmSynthetic
-                internal fun from(newPlanUnitWithPercentPrice: NewPlanUnitWithPercentPrice) =
-                    apply {
-                        cadence = newPlanUnitWithPercentPrice.cadence
-                        itemId = newPlanUnitWithPercentPrice.itemId
-                        modelType = newPlanUnitWithPercentPrice.modelType
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+            /** An alias for the price. */
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+            /** The property used to group this price on an invoice */
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
+
+            @JsonAnyGetter
+            @ExcludeMissing
+            fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanUnitWithPercentPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    unitWithPercentConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
+            fun toBuilder() = Builder().from(this)
+
+            companion object {
+
+                @JvmStatic fun builder() = Builder()
+            }
+
+            class Builder {
+
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
+                private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+
+                @JvmSynthetic
+                internal fun from(newPlanUnitWithPercentPrice: NewPlanUnitWithPercentPrice) =
+                    apply {
+                        cadence = newPlanUnitWithPercentPrice.cadence
+                        itemId = newPlanUnitWithPercentPrice.itemId
+                        modelType = newPlanUnitWithPercentPrice.modelType
                         name = newPlanUnitWithPercentPrice.name
                         unitWithPercentConfig = newPlanUnitWithPercentPrice.unitWithPercentConfig
                         billableMetricId = newPlanUnitWithPercentPrice.billableMetricId
@@ -12979,27 +17128,43 @@ constructor(
                     }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) = apply {
-                    this.unitWithPercentConfig = unitWithPercentConfig
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
                 }
 
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
+
+                /** The name of the price. */
+                fun name(name: JsonField<String>) = apply { this.name = name }
+
+                fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
+                    unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                fun unitWithPercentConfig(unitWithPercentConfig: JsonField<UnitWithPercentConfig>) =
+                    apply {
+                        this.unitWithPercentConfig = unitWithPercentConfig
+                    }
+
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -13008,13 +17173,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -13031,13 +17203,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -13047,10 +17227,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -13061,11 +17248,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -13073,22 +17265,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -13105,22 +17306,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -13130,12 +17343,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -13144,6 +17365,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -13333,6 +17561,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): UnitWithPercentConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13401,22 +17637,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13426,8 +17686,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -13440,10 +17700,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -13563,22 +17830,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13588,8 +17879,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -13602,10 +17893,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -13734,6 +18032,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13814,95 +18120,211 @@ constructor(
         class NewPlanPackageWithAllocationPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
             @JsonProperty("package_with_allocation_config")
-            private val packageWithAllocationConfig: PackageWithAllocationConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            fun modelType(): ModelType = modelType.getRequired("model_type")
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            fun name(): String = name.getRequired("name")
 
-            @JsonProperty("package_with_allocation_config")
             fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
+
+            /** The name of the price. */
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+            @JsonProperty("package_with_allocation_config")
+            @ExcludeMissing
+            fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                 packageWithAllocationConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -13910,12 +18332,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanPackageWithAllocationPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    packageWithAllocationConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -13925,21 +18371,24 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>? =
+                    null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13969,27 +18418,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 fun packageWithAllocationConfig(
                     packageWithAllocationConfig: PackageWithAllocationConfig
+                ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                fun packageWithAllocationConfig(
+                    packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                 ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -13998,13 +18463,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -14021,13 +18493,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -14037,10 +18517,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -14051,11 +18538,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -14063,22 +18555,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -14095,22 +18596,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -14120,12 +18633,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -14134,6 +18655,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -14323,6 +18851,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): PackageWithAllocationConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14392,22 +18928,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
+
+                /** The unit of billing period duration. */
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14417,8 +18977,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -14431,10 +18991,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -14554,22 +19121,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14579,8 +19170,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -14593,10 +19184,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -14725,6 +19323,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14780,119 +19386,236 @@ constructor(
 
                 override fun hashCode(): Int = hashCode
 
-                override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
-            }
+                override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
+            }
+
+            override fun equals(other: Any?): Boolean {
+                if (this === other) {
+                    return true
+                }
+
+                return /* spotless:off */ other is NewPlanPackageWithAllocationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && packageWithAllocationConfig == other.packageWithAllocationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+            }
+
+            /* spotless:off */
+            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, packageWithAllocationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+            /* spotless:on */
+
+            override fun hashCode(): Int = hashCode
+
+            override fun toString() =
+                "NewPlanPackageWithAllocationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, packageWithAllocationConfig=$packageWithAllocationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+        }
+
+        @NoAutoDetect
+        class NewPlanTierWithProrationPrice
+        @JsonCreator
+        private constructor(
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("tiered_with_proration_config")
+            @ExcludeMissing
+            private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-            override fun equals(other: Any?): Boolean {
-                if (this === other) {
-                    return true
-                }
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
-                return /* spotless:off */ other is NewPlanPackageWithAllocationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && packageWithAllocationConfig == other.packageWithAllocationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-            }
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-            /* spotless:off */
-            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, packageWithAllocationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-            /* spotless:on */
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-            override fun hashCode(): Int = hashCode
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            override fun toString() =
-                "NewPlanPackageWithAllocationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, packageWithAllocationConfig=$packageWithAllocationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-        }
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
-        @NoAutoDetect
-        class NewPlanTierWithProrationPrice
-        @JsonCreator
-        private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("tiered_with_proration_config")
-            private val tieredWithProrationConfig: TieredWithProrationConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-            @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonProperty("tiered_with_proration_config")
-            fun tieredWithProrationConfig(): TieredWithProrationConfig = tieredWithProrationConfig
+            @ExcludeMissing
+            fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
+                tieredWithProrationConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -14900,12 +19623,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanTierWithProrationPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    tieredWithProrationConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -14915,21 +19662,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -14958,27 +19707,43 @@ constructor(
                     }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 fun tieredWithProrationConfig(
                     tieredWithProrationConfig: TieredWithProrationConfig
+                ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                fun tieredWithProrationConfig(
+                    tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                 ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -14987,13 +19752,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -15010,13 +19782,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -15026,10 +19806,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -15040,11 +19827,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -15052,22 +19844,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -15084,22 +19885,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -15109,12 +19922,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -15123,6 +19944,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -15312,6 +20140,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): TieredWithProrationConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15381,22 +20217,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15406,8 +20266,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -15420,10 +20280,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -15543,22 +20410,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15568,8 +20459,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -15582,10 +20473,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -15714,6 +20612,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15777,111 +20683,228 @@ constructor(
                     return true
                 }
 
-                return /* spotless:off */ other is NewPlanTierWithProrationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithProrationConfig == other.tieredWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-            }
+                return /* spotless:off */ other is NewPlanTierWithProrationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithProrationConfig == other.tieredWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+            }
+
+            /* spotless:off */
+            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, tieredWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+            /* spotless:on */
+
+            override fun hashCode(): Int = hashCode
+
+            override fun toString() =
+                "NewPlanTierWithProrationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, tieredWithProrationConfig=$tieredWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+        }
+
+        @NoAutoDetect
+        class NewPlanUnitWithProrationPrice
+        @JsonCreator
+        private constructor(
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("unit_with_proration_config")
+            @ExcludeMissing
+            private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            fun unitWithProrationConfig(): UnitWithProrationConfig =
+                unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
 
-            /* spotless:off */
-            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, tieredWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-            /* spotless:on */
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-            override fun hashCode(): Int = hashCode
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-            override fun toString() =
-                "NewPlanTierWithProrationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, tieredWithProrationConfig=$tieredWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-        }
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-        @NoAutoDetect
-        class NewPlanUnitWithProrationPrice
-        @JsonCreator
-        private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("unit_with_proration_config")
-            private val unitWithProrationConfig: UnitWithProrationConfig,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-            @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonProperty("unit_with_proration_config")
-            fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+            @ExcludeMissing
+            fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                unitWithProrationConfig
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -15889,12 +20912,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanUnitWithProrationPrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    unitWithProrationConfig().validate()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -15904,21 +20951,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15947,28 +20996,42 @@ constructor(
                     }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                    apply {
-                        this.unitWithProrationConfig = unitWithProrationConfig
-                    }
+                    unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                fun unitWithProrationConfig(
+                    unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -15977,13 +21040,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -16000,13 +21070,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -16016,10 +21094,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -16030,11 +21115,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -16042,22 +21132,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -16074,22 +21173,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -16099,12 +21210,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -16113,6 +21232,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -16302,6 +21428,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): UnitWithProrationConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16370,22 +21504,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16395,8 +21553,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -16409,10 +21567,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -16532,22 +21697,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16557,8 +21746,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -16571,10 +21760,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -16703,6 +21899,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16766,111 +21970,228 @@ constructor(
                     return true
                 }
 
-                return /* spotless:off */ other is NewPlanUnitWithProrationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithProrationConfig == other.unitWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-            }
+                return /* spotless:off */ other is NewPlanUnitWithProrationPrice && cadence == other.cadence && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithProrationConfig == other.unitWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && currency == other.currency && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+            }
+
+            /* spotless:off */
+            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, unitWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+            /* spotless:on */
+
+            override fun hashCode(): Int = hashCode
+
+            override fun toString() =
+                "NewPlanUnitWithProrationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, unitWithProrationConfig=$unitWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+        }
+
+        @NoAutoDetect
+        class NewPlanGroupedAllocationPrice
+        @JsonCreator
+        private constructor(
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("grouped_allocation_config")
+            @ExcludeMissing
+            private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            fun groupedAllocationConfig(): GroupedAllocationConfig =
+                groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-            /* spotless:off */
-            private val hashCode: Int by lazy { Objects.hash(cadence, itemId, modelType, name, unitWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, currency, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-            /* spotless:on */
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-            override fun hashCode(): Int = hashCode
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            override fun toString() =
-                "NewPlanUnitWithProrationPrice{cadence=$cadence, itemId=$itemId, modelType=$modelType, name=$name, unitWithProrationConfig=$unitWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-        }
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
 
-        @NoAutoDetect
-        class NewPlanGroupedAllocationPrice
-        @JsonCreator
-        private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("grouped_allocation_config")
-            private val groupedAllocationConfig: GroupedAllocationConfig,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-            @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             @JsonProperty("grouped_allocation_config")
-            fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+            @ExcludeMissing
+            fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                groupedAllocationConfig
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -16878,12 +22199,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanGroupedAllocationPrice = apply {
+                if (!validated) {
+                    cadence()
+                    groupedAllocationConfig().validate()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -16893,21 +22238,23 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -16936,28 +22283,42 @@ constructor(
                     }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                    apply {
-                        this.groupedAllocationConfig = groupedAllocationConfig
-                    }
+                    groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                fun groupedAllocationConfig(
+                    groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -16966,13 +22327,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -16989,13 +22357,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -17005,10 +22381,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -17019,11 +22402,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -17031,22 +22419,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -17063,22 +22460,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -17088,12 +22497,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -17102,6 +22519,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -17240,6 +22664,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): GroupedAllocationConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17359,22 +22791,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17384,8 +22840,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -17398,10 +22854,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -17521,22 +22984,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17546,8 +23033,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -17560,10 +23047,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -17692,6 +23186,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17768,99 +23270,216 @@ constructor(
                 "NewPlanGroupedAllocationPrice{cadence=$cadence, groupedAllocationConfig=$groupedAllocationConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, currency=$currency, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
         }
 
-        @NoAutoDetect
-        class NewPlanGroupedWithProratedMinimumPrice
-        @JsonCreator
-        private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("grouped_with_prorated_minimum_config")
-            private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-            @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-            @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
-            @JsonAnySetter
-            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-        ) {
+        @NoAutoDetect
+        class NewPlanGroupedWithProratedMinimumPrice
+        @JsonCreator
+        private constructor(
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("grouped_with_prorated_minimum_config")
+            @ExcludeMissing
+            private val groupedWithProratedMinimumConfig:
+                JsonField<GroupedWithProratedMinimumConfig> =
+                JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+            @JsonProperty("billing_cycle_configuration")
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("invoicing_cycle_configuration")
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
+            @JsonAnySetter
+            private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+        ) {
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
+                groupedWithProratedMinimumConfig.getRequired("grouped_with_prorated_minimum_config")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             @JsonProperty("grouped_with_prorated_minimum_config")
-            fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
+            @ExcludeMissing
+            fun _groupedWithProratedMinimumConfig(): JsonField<GroupedWithProratedMinimumConfig> =
                 groupedWithProratedMinimumConfig
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -17868,12 +23487,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanGroupedWithProratedMinimumPrice = apply {
+                if (!validated) {
+                    cadence()
+                    groupedWithProratedMinimumConfig().validate()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17883,22 +23526,25 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig? =
+                private var cadence: JsonField<Cadence>? = null
+                private var groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig>? =
                     null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17928,29 +23574,45 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 fun groupedWithProratedMinimumConfig(
                     groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                ) = groupedWithProratedMinimumConfig(JsonField.of(groupedWithProratedMinimumConfig))
+
+                fun groupedWithProratedMinimumConfig(
+                    groupedWithProratedMinimumConfig: JsonField<GroupedWithProratedMinimumConfig>
                 ) = apply {
                     this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                 }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -17959,13 +23621,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -17982,13 +23651,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -17998,10 +23675,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -18012,11 +23696,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -18024,22 +23713,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -18056,22 +23754,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -18081,12 +23791,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -18095,6 +23813,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -18233,6 +23958,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): GroupedWithProratedMinimumConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18355,22 +24088,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18380,8 +24137,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -18394,10 +24151,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -18517,22 +24281,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18542,8 +24330,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -18556,10 +24344,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -18688,6 +24483,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18768,95 +24571,212 @@ constructor(
         class NewPlanGroupedWithMeteredMinimumPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
             @JsonProperty("grouped_with_metered_minimum_config")
-            private val groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val groupedWithMeteredMinimumConfig:
+                JsonField<GroupedWithMeteredMinimumConfig> =
+                JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
-            @JsonProperty("grouped_with_metered_minimum_config")
             fun groupedWithMeteredMinimumConfig(): GroupedWithMeteredMinimumConfig =
+                groupedWithMeteredMinimumConfig.getRequired("grouped_with_metered_minimum_config")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            @JsonProperty("grouped_with_metered_minimum_config")
+            @ExcludeMissing
+            fun _groupedWithMeteredMinimumConfig(): JsonField<GroupedWithMeteredMinimumConfig> =
                 groupedWithMeteredMinimumConfig
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -18864,12 +24784,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanGroupedWithMeteredMinimumPrice = apply {
+                if (!validated) {
+                    cadence()
+                    groupedWithMeteredMinimumConfig().validate()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -18879,21 +24823,25 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var groupedWithMeteredMinimumConfig:
+                    JsonField<GroupedWithMeteredMinimumConfig>? =
+                    null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18923,27 +24871,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 fun groupedWithMeteredMinimumConfig(
                     groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig
+                ) = groupedWithMeteredMinimumConfig(JsonField.of(groupedWithMeteredMinimumConfig))
+
+                fun groupedWithMeteredMinimumConfig(
+                    groupedWithMeteredMinimumConfig: JsonField<GroupedWithMeteredMinimumConfig>
                 ) = apply { this.groupedWithMeteredMinimumConfig = groupedWithMeteredMinimumConfig }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -18952,13 +24916,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -18975,13 +24946,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -18991,10 +24970,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -19005,11 +24991,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -19017,22 +25008,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -19049,22 +25049,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -19074,12 +25086,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -19088,6 +25108,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -19226,6 +25253,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): GroupedWithMeteredMinimumConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19347,22 +25382,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19372,8 +25431,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -19386,10 +25445,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -19509,22 +25575,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19534,8 +25624,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -19548,10 +25638,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -19680,6 +25777,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19760,95 +25865,211 @@ constructor(
         class NewPlanMatrixWithDisplayNamePrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
             @JsonProperty("matrix_with_display_name_config")
-            private val matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig> =
+                JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            fun itemId(): String = itemId.getRequired("item_id")
 
-            @JsonProperty("matrix_with_display_name_config")
             fun matrixWithDisplayNameConfig(): MatrixWithDisplayNameConfig =
+                matrixWithDisplayNameConfig.getRequired("matrix_with_display_name_config")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            /** The id of the item the plan will be associated with. */
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+            @JsonProperty("matrix_with_display_name_config")
+            @ExcludeMissing
+            fun _matrixWithDisplayNameConfig(): JsonField<MatrixWithDisplayNameConfig> =
                 matrixWithDisplayNameConfig
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -19856,12 +26077,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanMatrixWithDisplayNamePrice = apply {
+                if (!validated) {
+                    cadence()
+                    itemId()
+                    matrixWithDisplayNameConfig().validate()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -19871,21 +26116,24 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>? =
+                    null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19915,27 +26163,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
                 fun matrixWithDisplayNameConfig(
                     matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig
+                ) = matrixWithDisplayNameConfig(JsonField.of(matrixWithDisplayNameConfig))
+
+                fun matrixWithDisplayNameConfig(
+                    matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>
                 ) = apply { this.matrixWithDisplayNameConfig = matrixWithDisplayNameConfig }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -19944,13 +26208,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -19967,13 +26238,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -19983,10 +26262,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -19997,34 +26283,48 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: Optional<String>) = currency(currency.orElse(null))
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -20041,22 +26341,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -20066,12 +26378,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -20080,6 +26400,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -20218,6 +26545,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): MatrixWithDisplayNameConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20338,22 +26673,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20363,8 +26722,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -20377,10 +26736,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -20500,22 +26866,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20525,8 +26915,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -20539,10 +26929,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -20671,6 +27068,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20752,93 +27157,210 @@ constructor(
         @JsonCreator
         private constructor(
             @JsonProperty("bulk_with_proration_config")
-            private val bulkWithProrationConfig: BulkWithProrationConfig,
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                JsonMissing.of(),
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
+            fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+            /** The cadence to bill for this price on. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
             @JsonProperty("bulk_with_proration_config")
-            fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+            @ExcludeMissing
+            fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                bulkWithProrationConfig
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -20846,12 +27368,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanBulkWithProrationPrice = apply {
+                if (!validated) {
+                    bulkWithProrationConfig().validate()
+                    cadence()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -20861,21 +27407,23 @@ constructor(
 
             class Builder {
 
-                private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                private var cadence: Cadence? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20904,28 +27452,42 @@ constructor(
                     }
 
                 fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                    apply {
-                        this.bulkWithProrationConfig = bulkWithProrationConfig
-                    }
+                    bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                fun bulkWithProrationConfig(
+                    bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -20934,13 +27496,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -20957,13 +27526,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -20973,10 +27550,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -20987,11 +27571,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -20999,22 +27588,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -21031,22 +27629,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -21056,12 +27666,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -21070,6 +27688,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -21127,6 +27752,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BulkWithProrationConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21327,22 +27960,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21352,8 +28009,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -21366,10 +28023,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -21489,22 +28153,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21514,8 +28202,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -21528,10 +28216,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -21660,6 +28355,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21740,95 +28443,211 @@ constructor(
         class NewPlanGroupedTieredPackagePrice
         @JsonCreator
         private constructor(
-            @JsonProperty("cadence") private val cadence: Cadence,
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
             @JsonProperty("grouped_tiered_package_config")
-            private val groupedTieredPackageConfig: GroupedTieredPackageConfig,
-            @JsonProperty("item_id") private val itemId: String,
-            @JsonProperty("model_type") private val modelType: ModelType,
-            @JsonProperty("name") private val name: String,
-            @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-            @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+            @ExcludeMissing
+            private val groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig> =
+                JsonMissing.of(),
+            @JsonProperty("item_id")
+            @ExcludeMissing
+            private val itemId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            private val modelType: JsonField<ModelType> = JsonMissing.of(),
+            @JsonProperty("name")
+            @ExcludeMissing
+            private val name: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billable_metric_id")
+            @ExcludeMissing
+            private val billableMetricId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("billed_in_advance")
+            @ExcludeMissing
+            private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
             @JsonProperty("billing_cycle_configuration")
-            private val billingCycleConfiguration: BillingCycleConfiguration?,
-            @JsonProperty("conversion_rate") private val conversionRate: Double?,
-            @JsonProperty("currency") private val currency: String?,
-            @JsonProperty("external_price_id") private val externalPriceId: String?,
-            @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-            @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+            @ExcludeMissing
+            private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("conversion_rate")
+            @ExcludeMissing
+            private val conversionRate: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("external_price_id")
+            @ExcludeMissing
+            private val externalPriceId: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("fixed_price_quantity")
+            @ExcludeMissing
+            private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("invoice_grouping_key")
+            @ExcludeMissing
+            private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
             @JsonProperty("invoicing_cycle_configuration")
-            private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-            @JsonProperty("metadata") private val metadata: Metadata?,
+            @ExcludeMissing
+            private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of(),
+            @JsonProperty("metadata")
+            @ExcludeMissing
+            private val metadata: JsonField<Metadata> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The cadence to bill for this price on. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            fun cadence(): Cadence = cadence.getRequired("cadence")
 
-            @JsonProperty("grouped_tiered_package_config")
             fun groupedTieredPackageConfig(): GroupedTieredPackageConfig =
+                groupedTieredPackageConfig.getRequired("grouped_tiered_package_config")
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(): String = itemId.getRequired("item_id")
+
+            fun modelType(): ModelType = modelType.getRequired("model_type")
+
+            /** The name of the price. */
+            fun name(): String = name.getRequired("name")
+
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(): Optional<String> =
+                Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(): Optional<Boolean> =
+                Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                Optional.ofNullable(
+                    billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                )
+
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(): Optional<Double> =
+                Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+            /**
+             * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
+             * is billed.
+             */
+            fun currency(): Optional<String> = Optional.ofNullable(currency.getNullable("currency"))
+
+            /** An alias for the price. */
+            fun externalPriceId(): Optional<String> =
+                Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(): Optional<Double> =
+                Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(): Optional<String> =
+                Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                Optional.ofNullable(
+                    invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                )
+
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(): Optional<Metadata> =
+                Optional.ofNullable(metadata.getNullable("metadata"))
+
+            /** The cadence to bill for this price on. */
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+            @JsonProperty("grouped_tiered_package_config")
+            @ExcludeMissing
+            fun _groupedTieredPackageConfig(): JsonField<GroupedTieredPackageConfig> =
                 groupedTieredPackageConfig
 
             /** The id of the item the plan will be associated with. */
-            @JsonProperty("item_id") fun itemId(): String = itemId
+            @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JsonProperty("model_type") fun modelType(): ModelType = modelType
+            @JsonProperty("model_type")
+            @ExcludeMissing
+            fun _modelType(): JsonField<ModelType> = modelType
 
             /** The name of the price. */
-            @JsonProperty("name") fun name(): String = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
             @JsonProperty("billable_metric_id")
-            fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+            @ExcludeMissing
+            fun _billableMetricId(): JsonField<String> = billableMetricId
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
             @JsonProperty("billed_in_advance")
-            fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+            @ExcludeMissing
+            fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             @JsonProperty("billing_cycle_configuration")
-            fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                Optional.ofNullable(billingCycleConfiguration)
+            @ExcludeMissing
+            fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                billingCycleConfiguration
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             @JsonProperty("conversion_rate")
-            fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+            @ExcludeMissing
+            fun _conversionRate(): JsonField<Double> = conversionRate
 
             /**
              * An ISO 4217 currency string, or custom pricing unit identifier, in which this price
              * is billed.
              */
-            @JsonProperty("currency")
-            fun currency(): Optional<String> = Optional.ofNullable(currency)
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /** An alias for the price. */
             @JsonProperty("external_price_id")
-            fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+            @ExcludeMissing
+            fun _externalPriceId(): JsonField<String> = externalPriceId
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
             @JsonProperty("fixed_price_quantity")
-            fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+            @ExcludeMissing
+            fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
             /** The property used to group this price on an invoice */
             @JsonProperty("invoice_grouping_key")
-            fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+            @ExcludeMissing
+            fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             @JsonProperty("invoicing_cycle_configuration")
-            fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                Optional.ofNullable(invoicingCycleConfiguration)
+            @ExcludeMissing
+            fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                invoicingCycleConfiguration
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -21836,12 +28655,36 @@ constructor(
              * setting `metadata` to `null`.
              */
             @JsonProperty("metadata")
-            fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+            @ExcludeMissing
+            fun _metadata(): JsonField<Metadata> = metadata
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): NewPlanGroupedTieredPackagePrice = apply {
+                if (!validated) {
+                    cadence()
+                    groupedTieredPackageConfig().validate()
+                    itemId()
+                    modelType()
+                    name()
+                    billableMetricId()
+                    billedInAdvance()
+                    billingCycleConfiguration().map { it.validate() }
+                    conversionRate()
+                    currency()
+                    externalPriceId()
+                    fixedPriceQuantity()
+                    invoiceGroupingKey()
+                    invoicingCycleConfiguration().map { it.validate() }
+                    metadata().map { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21851,21 +28694,24 @@ constructor(
 
             class Builder {
 
-                private var cadence: Cadence? = null
-                private var groupedTieredPackageConfig: GroupedTieredPackageConfig? = null
-                private var itemId: String? = null
-                private var modelType: ModelType? = null
-                private var name: String? = null
-                private var billableMetricId: String? = null
-                private var billedInAdvance: Boolean? = null
-                private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                private var conversionRate: Double? = null
-                private var currency: String? = null
-                private var externalPriceId: String? = null
-                private var fixedPriceQuantity: Double? = null
-                private var invoiceGroupingKey: String? = null
-                private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                private var metadata: Metadata? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>? =
+                    null
+                private var itemId: JsonField<String>? = null
+                private var modelType: JsonField<ModelType>? = null
+                private var name: JsonField<String>? = null
+                private var billableMetricId: JsonField<String> = JsonMissing.of()
+                private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of()
+                private var conversionRate: JsonField<Double> = JsonMissing.of()
+                private var currency: JsonField<String> = JsonMissing.of()
+                private var externalPriceId: JsonField<String> = JsonMissing.of()
+                private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of()
+                private var metadata: JsonField<Metadata> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21895,27 +28741,43 @@ constructor(
                 }
 
                 /** The cadence to bill for this price on. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                /** The cadence to bill for this price on. */
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 fun groupedTieredPackageConfig(
                     groupedTieredPackageConfig: GroupedTieredPackageConfig
+                ) = groupedTieredPackageConfig(JsonField.of(groupedTieredPackageConfig))
+
+                fun groupedTieredPackageConfig(
+                    groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>
                 ) = apply { this.groupedTieredPackageConfig = groupedTieredPackageConfig }
 
                 /** The id of the item the plan will be associated with. */
-                fun itemId(itemId: String) = apply { this.itemId = itemId }
+                fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                fun modelType(modelType: JsonField<ModelType>) = apply {
+                    this.modelType = modelType
+                }
+
+                /** The name of the price. */
+                fun name(name: String) = name(JsonField.of(name))
 
                 /** The name of the price. */
-                fun name(name: String) = apply { this.name = name }
+                fun name(name: JsonField<String>) = apply { this.name = name }
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
-                fun billableMetricId(billableMetricId: String?) = apply {
-                    this.billableMetricId = billableMetricId
-                }
+                fun billableMetricId(billableMetricId: String?) =
+                    billableMetricId(JsonField.ofNullable(billableMetricId))
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
@@ -21924,13 +28786,20 @@ constructor(
                 fun billableMetricId(billableMetricId: Optional<String>) =
                     billableMetricId(billableMetricId.orElse(null))
 
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                    this.billableMetricId = billableMetricId
+                }
+
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
-                fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                    this.billedInAdvance = billedInAdvance
-                }
+                fun billedInAdvance(billedInAdvance: Boolean?) =
+                    billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
@@ -21947,13 +28816,21 @@ constructor(
                 fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                     billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                    this.billedInAdvance = billedInAdvance
+                }
+
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 fun billingCycleConfiguration(
                     billingCycleConfiguration: BillingCycleConfiguration?
-                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
@@ -21963,10 +28840,17 @@ constructor(
                     billingCycleConfiguration: Optional<BillingCycleConfiguration>
                 ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(
+                    billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
-                fun conversionRate(conversionRate: Double?) = apply {
-                    this.conversionRate = conversionRate
-                }
+                fun conversionRate(conversionRate: Double?) =
+                    conversionRate(JsonField.ofNullable(conversionRate))
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 fun conversionRate(conversionRate: Double) =
@@ -21977,11 +28861,16 @@ constructor(
                 fun conversionRate(conversionRate: Optional<Double>) =
                     conversionRate(conversionRate.orElse(null) as Double?)
 
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                    this.conversionRate = conversionRate
+                }
+
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
-                fun currency(currency: String?) = apply { this.currency = currency }
+                fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -21989,22 +28878,31 @@ constructor(
                  */
                 fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                 /** An alias for the price. */
-                fun externalPriceId(externalPriceId: String?) = apply {
-                    this.externalPriceId = externalPriceId
-                }
+                fun externalPriceId(externalPriceId: String?) =
+                    externalPriceId(JsonField.ofNullable(externalPriceId))
 
                 /** An alias for the price. */
                 fun externalPriceId(externalPriceId: Optional<String>) =
                     externalPriceId(externalPriceId.orElse(null))
 
+                /** An alias for the price. */
+                fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                    this.externalPriceId = externalPriceId
+                }
+
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
-                fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                    this.fixedPriceQuantity = fixedPriceQuantity
-                }
+                fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                    fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
@@ -22021,22 +28919,34 @@ constructor(
                 fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                     fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                /** The property used to group this price on an invoice */
-                fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                    this.invoiceGroupingKey = invoiceGroupingKey
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                    this.fixedPriceQuantity = fixedPriceQuantity
                 }
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                    invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                 /** The property used to group this price on an invoice */
                 fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                     invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                    this.invoiceGroupingKey = invoiceGroupingKey
+                }
+
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 fun invoicingCycleConfiguration(
                     invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
@@ -22046,12 +28956,20 @@ constructor(
                     invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                 ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(
+                    invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
                  * by setting the value to `null`, and the entire metadata mapping can be cleared by
                  * setting `metadata` to `null`.
                  */
-                fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -22060,6 +28978,13 @@ constructor(
                  */
                 fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -22198,6 +29123,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): GroupedTieredPackageConfig = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22318,22 +29251,46 @@ constructor(
             class BillingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): BillingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22343,8 +29300,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -22357,10 +29314,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -22480,22 +29444,46 @@ constructor(
             class InvoicingCycleConfiguration
             @JsonCreator
             private constructor(
-                @JsonProperty("duration") private val duration: Long,
-                @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                @JsonProperty("duration")
+                @ExcludeMissing
+                private val duration: JsonField<Long> = JsonMissing.of(),
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The duration of the billing period. */
-                @JsonProperty("duration") fun duration(): Long = duration
+                fun duration(): Long = duration.getRequired("duration")
+
+                /** The unit of billing period duration. */
+                fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                /** The duration of the billing period. */
+                @JsonProperty("duration")
+                @ExcludeMissing
+                fun _duration(): JsonField<Long> = duration
 
                 /** The unit of billing period duration. */
-                @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                @JsonProperty("duration_unit")
+                @ExcludeMissing
+                fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): InvoicingCycleConfiguration = apply {
+                    if (!validated) {
+                        duration()
+                        durationUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22505,8 +29493,8 @@ constructor(
 
                 class Builder {
 
-                    private var duration: Long? = null
-                    private var durationUnit: DurationUnit? = null
+                    private var duration: JsonField<Long>? = null
+                    private var durationUnit: JsonField<DurationUnit>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -22519,10 +29507,17 @@ constructor(
                         }
 
                     /** The duration of the billing period. */
-                    fun duration(duration: Long) = apply { this.duration = duration }
+                    fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                    /** The duration of the billing period. */
+                    fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(durationUnit: DurationUnit) =
+                        durationUnit(JsonField.of(durationUnit))
 
                     /** The unit of billing period duration. */
-                    fun durationUnit(durationUnit: DurationUnit) = apply {
+                    fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                         this.durationUnit = durationUnit
                     }
 
@@ -22651,6 +29646,14 @@ constructor(
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Metadata = apply {
+                    if (!validated) {
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22745,6 +29748,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdFetchParams.kt
index 6a883841..dad40693 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdFetchParams.kt
@@ -7,6 +7,22 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch [plan](../guides/concepts##plan-and-price) details given an
+ * external_plan_id identifier. It returns information about the prices included in the plan and
+ * their configuration, as well as the product that the plan is attached to.
+ *
+ * If multiple plans are found to contain the specified external_plan_id, the active plans will take
+ * priority over archived ones, and among those, the endpoint will return the most recently created
+ * plan.
+ *
+ * ## Serialized prices
+ *
+ * Orb supports a few different pricing models out of the box. Each of these models is serialized
+ * differently in a given [Price](../guides/concepts#plan-and-price) object. The `model_type` field
+ * determines the key for the configuration object that is present. A detailed explanation of price
+ * types can be found in the [Price schema](../guides/concepts#plan-and-price). "
+ */
 class PlanExternalPlanIdFetchParams
 constructor(
     private val externalPlanId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdUpdateParams.kt
index 48314c06..bca38781 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanExternalPlanIdUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to update the `external_plan_id`, and `metadata` of an existing plan.
+ *
+ * Other fields on a customer are currently immutable.
+ */
 class PlanExternalPlanIdUpdateParams
 constructor(
     private val otherExternalPlanId: String,
@@ -39,12 +46,25 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * An optional user-defined ID for this plan resource, used throughout the system as an alias
+     * for this Plan. Use this field to identify a plan by an existing identifier in your system.
+     */
+    fun _externalPlanId(): JsonField<String> = body._externalPlanId()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): PlanExternalPlanIdUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -62,31 +82,61 @@ constructor(
     class PlanExternalPlanIdUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("external_plan_id") private val externalPlanId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        private val externalPlanId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * An optional user-defined ID for this plan resource, used throughout the system as an
+         * alias for this Plan. Use this field to identify a plan by an existing identifier in your
+         * system.
+         */
+        fun externalPlanId(): Optional<String> =
+            Optional.ofNullable(externalPlanId.getNullable("external_plan_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
         @JsonProperty("external_plan_id")
-        fun externalPlanId(): Optional<String> = Optional.ofNullable(externalPlanId)
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PlanExternalPlanIdUpdateBody = apply {
+            if (!validated) {
+                externalPlanId()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -96,8 +146,8 @@ constructor(
 
         class Builder {
 
-            private var externalPlanId: String? = null
-            private var metadata: Metadata? = null
+            private var externalPlanId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -113,9 +163,8 @@ constructor(
              * alias for this Plan. Use this field to identify a plan by an existing identifier in
              * your system.
              */
-            fun externalPlanId(externalPlanId: String?) = apply {
-                this.externalPlanId = externalPlanId
-            }
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
 
             /**
              * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -125,12 +174,21 @@ constructor(
             fun externalPlanId(externalPlanId: Optional<String>) =
                 externalPlanId(externalPlanId.orElse(null))
 
+            /**
+             * An optional user-defined ID for this plan resource, used throughout the system as an
+             * alias for this Plan. Use this field to identify a plan by an existing identifier in
+             * your system.
+             */
+            fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+                this.externalPlanId = externalPlanId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -139,6 +197,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -227,6 +292,15 @@ constructor(
         fun externalPlanId(externalPlanId: Optional<String>) =
             externalPlanId(externalPlanId.orElse(null))
 
+        /**
+         * An optional user-defined ID for this plan resource, used throughout the system as an
+         * alias for this Plan. Use this field to identify a plan by an existing identifier in your
+         * system.
+         */
+        fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+            body.externalPlanId(externalPlanId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -241,6 +315,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -339,25 +439,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PlanExternalPlanIdUpdateParams =
             PlanExternalPlanIdUpdateParams(
                 checkNotNull(otherExternalPlanId) {
@@ -386,6 +467,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanFetchParams.kt
index 5046e958..d166ce93 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanFetchParams.kt
@@ -7,6 +7,23 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch [plan](../guides/concepts##plan-and-price) details given a plan
+ * identifier. It returns information about the prices included in the plan and their configuration,
+ * as well as the product that the plan is attached to.
+ *
+ * ## Serialized prices
+ *
+ * Orb supports a few different pricing models out of the box. Each of these models is serialized
+ * differently in a given [Price](../guides/concepts#plan-and-price) object. The `model_type` field
+ * determines the key for the configuration object that is present. A detailed explanation of price
+ * types can be found in the [Price schema](../guides/concepts#plan-and-price).
+ *
+ * ## Phases
+ *
+ * Orb supports plan phases, also known as contract ramps. For plans with phases, the serialized
+ * prices refer to all prices across all phases.
+ */
 class PlanFetchParams
 constructor(
     private val planId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanListParams.kt
index 5db830a7..00393917 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanListParams.kt
@@ -14,6 +14,12 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all [plans](../guides/concepts##plan-and-price) for an account in
+ * a list format. The list of plans is ordered starting from the most recently created plan. The
+ * response also includes [`pagination_metadata`](../reference/pagination), which lets the caller
+ * retrieve the next page of results if they exist.
+ */
 class PlanListParams
 constructor(
     private val createdAtGt: OffsetDateTime?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanUpdateParams.kt
index 224fbc77..ef85ef4f 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PlanUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,11 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to update the `external_plan_id`, and `metadata` of an existing plan.
+ *
+ * Other fields on a customer are currently immutable.
+ */
 class PlanUpdateParams
 constructor(
     private val planId: String,
@@ -39,12 +46,25 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * An optional user-defined ID for this plan resource, used throughout the system as an alias
+     * for this Plan. Use this field to identify a plan by an existing identifier in your system.
+     */
+    fun _externalPlanId(): JsonField<String> = body._externalPlanId()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): PlanUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -62,31 +82,61 @@ constructor(
     class PlanUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("external_plan_id") private val externalPlanId: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        private val externalPlanId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * An optional user-defined ID for this plan resource, used throughout the system as an
+         * alias for this Plan. Use this field to identify a plan by an existing identifier in your
+         * system.
+         */
+        fun externalPlanId(): Optional<String> =
+            Optional.ofNullable(externalPlanId.getNullable("external_plan_id"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
         @JsonProperty("external_plan_id")
-        fun externalPlanId(): Optional<String> = Optional.ofNullable(externalPlanId)
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PlanUpdateBody = apply {
+            if (!validated) {
+                externalPlanId()
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -96,8 +146,8 @@ constructor(
 
         class Builder {
 
-            private var externalPlanId: String? = null
-            private var metadata: Metadata? = null
+            private var externalPlanId: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -112,9 +162,8 @@ constructor(
              * alias for this Plan. Use this field to identify a plan by an existing identifier in
              * your system.
              */
-            fun externalPlanId(externalPlanId: String?) = apply {
-                this.externalPlanId = externalPlanId
-            }
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
 
             /**
              * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -124,12 +173,21 @@ constructor(
             fun externalPlanId(externalPlanId: Optional<String>) =
                 externalPlanId(externalPlanId.orElse(null))
 
+            /**
+             * An optional user-defined ID for this plan resource, used throughout the system as an
+             * alias for this Plan. Use this field to identify a plan by an existing identifier in
+             * your system.
+             */
+            fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+                this.externalPlanId = externalPlanId
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -138,6 +196,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -223,6 +288,15 @@ constructor(
         fun externalPlanId(externalPlanId: Optional<String>) =
             externalPlanId(externalPlanId.orElse(null))
 
+        /**
+         * An optional user-defined ID for this plan resource, used throughout the system as an
+         * alias for this Plan. Use this field to identify a plan by an existing identifier in your
+         * system.
+         */
+        fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+            body.externalPlanId(externalPlanId)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -237,6 +311,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -335,25 +435,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PlanUpdateParams =
             PlanUpdateParams(
                 checkNotNull(planId) { "`planId` is required but was not set" },
@@ -380,6 +461,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Price.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Price.kt
index 50f89152..7019d5b1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Price.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Price.kt
@@ -1137,64 +1137,86 @@ private constructor(
 
         fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
-        @JsonProperty("unit_config") @ExcludeMissing fun _unitConfig() = unitConfig
+        @JsonProperty("unit_config")
+        @ExcludeMissing
+        fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -1240,31 +1262,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var unitConfig: JsonField<UnitConfig> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var unitConfig: JsonField<UnitConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1299,8 +1319,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -1317,8 +1340,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -1330,8 +1359,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -1341,27 +1373,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -1371,11 +1431,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -1395,11 +1461,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -1413,7 +1485,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -1450,29 +1529,39 @@ private constructor(
 
             fun build(): UnitPrice =
                 UnitPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    unitConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(unitConfig) { "`unitConfig` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1490,7 +1579,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1514,7 +1603,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1549,7 +1638,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -1588,9 +1681,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1615,8 +1710,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1662,8 +1757,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1842,9 +1937,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1869,8 +1966,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1915,8 +2012,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -1957,9 +2056,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -1984,8 +2085,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2032,8 +2133,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2131,9 +2232,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2158,8 +2259,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2201,8 +2302,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2255,10 +2356,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2283,13 +2386,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -2306,7 +2409,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -2342,8 +2462,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2479,10 +2604,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2507,13 +2634,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -2530,7 +2657,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -2566,8 +2710,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -2713,7 +2862,9 @@ private constructor(
             fun unitAmount(): String = unitAmount.getRequired("unit_amount")
 
             /** Rate per unit of usage */
-            @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+            @JsonProperty("unit_amount")
+            @ExcludeMissing
+            fun _unitAmount(): JsonField<String> = unitAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -2737,7 +2888,7 @@ private constructor(
 
             class Builder {
 
-                private var unitAmount: JsonField<String> = JsonMissing.of()
+                private var unitAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2776,7 +2927,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): UnitConfig = UnitConfig(unitAmount, additionalProperties.toImmutable())
+                fun build(): UnitConfig =
+                    UnitConfig(
+                        checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -2953,64 +3108,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("package_config") @ExcludeMissing fun _packageConfig() = packageConfig
+        @JsonProperty("package_config")
+        @ExcludeMissing
+        fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -3056,31 +3233,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var packageConfig: JsonField<PackageConfig> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var packageConfig: JsonField<PackageConfig>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3115,8 +3290,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -3133,8 +3311,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -3146,8 +3330,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -3157,27 +3344,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -3187,11 +3402,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -3211,11 +3432,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -3236,7 +3463,14 @@ private constructor(
                 this.packageConfig = packageConfig
             }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -3267,29 +3501,39 @@ private constructor(
 
             fun build(): PackagePrice =
                 PackagePrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    packageConfig,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(packageConfig) { "`packageConfig` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -3307,7 +3551,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3331,7 +3575,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3366,7 +3610,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -3405,9 +3653,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3432,8 +3682,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3479,8 +3729,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3659,9 +3909,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3686,8 +3938,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3732,8 +3984,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3774,9 +4028,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3801,8 +4057,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3849,8 +4105,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3948,9 +4204,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3975,8 +4231,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4018,8 +4274,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4072,10 +4328,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4100,13 +4358,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -4123,7 +4381,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -4159,8 +4434,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4296,10 +4576,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4324,13 +4606,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -4347,7 +4629,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -4383,8 +4682,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4482,13 +4786,17 @@ private constructor(
             fun packageSize(): Long = packageSize.getRequired("package_size")
 
             /** A currency amount to rate usage by */
-            @JsonProperty("package_amount") @ExcludeMissing fun _packageAmount() = packageAmount
+            @JsonProperty("package_amount")
+            @ExcludeMissing
+            fun _packageAmount(): JsonField<String> = packageAmount
 
             /**
              * An integer amount to represent package size. For example, 1000 here would divide
              * usage by 1000 before multiplying by package_amount in rating
              */
-            @JsonProperty("package_size") @ExcludeMissing fun _packageSize() = packageSize
+            @JsonProperty("package_size")
+            @ExcludeMissing
+            fun _packageSize(): JsonField<Long> = packageSize
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -4513,8 +4821,8 @@ private constructor(
 
             class Builder {
 
-                private var packageAmount: JsonField<String> = JsonMissing.of()
-                private var packageSize: JsonField<Long> = JsonMissing.of()
+                private var packageAmount: JsonField<String>? = null
+                private var packageSize: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4571,8 +4879,10 @@ private constructor(
 
                 fun build(): PackageConfig =
                     PackageConfig(
-                        packageAmount,
-                        packageSize,
+                        checkNotNull(packageAmount) {
+                            "`packageAmount` is required but was not set"
+                        },
+                        checkNotNull(packageSize) { "`packageSize` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4808,64 +5118,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("matrix_config") @ExcludeMissing fun _matrixConfig() = matrixConfig
+        @JsonProperty("matrix_config")
+        @ExcludeMissing
+        fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4911,31 +5243,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var matrixConfig: JsonField<MatrixConfig> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var matrixConfig: JsonField<MatrixConfig>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4970,8 +5300,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -4988,8 +5321,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -5001,8 +5340,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -5012,27 +5354,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -5048,11 +5418,17 @@ private constructor(
                 this.matrixConfig = matrixConfig
             }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -5072,11 +5448,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -5090,7 +5472,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -5121,29 +5510,39 @@ private constructor(
 
             fun build(): MatrixPrice =
                 MatrixPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    matrixConfig,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(matrixConfig) { "`matrixConfig` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5161,7 +5560,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5185,7 +5584,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5220,7 +5619,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -5259,9 +5662,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5286,8 +5691,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5333,8 +5738,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5513,9 +5918,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5540,8 +5947,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5586,8 +5993,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5628,9 +6037,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5655,8 +6066,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5703,8 +6114,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5802,9 +6213,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5829,8 +6240,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5872,8 +6283,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5925,13 +6336,17 @@ private constructor(
             /** Default per unit rate for any usage not bucketed into a specified matrix_value */
             @JsonProperty("default_unit_amount")
             @ExcludeMissing
-            fun _defaultUnitAmount() = defaultUnitAmount
+            fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
             /** One or two event property values to evaluate matrix groups by */
-            @JsonProperty("dimensions") @ExcludeMissing fun _dimensions() = dimensions
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            fun _dimensions(): JsonField<List<String?>> = dimensions
 
             /** Matrix values for specified matrix grouping keys */
-            @JsonProperty("matrix_values") @ExcludeMissing fun _matrixValues() = matrixValues
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5957,16 +6372,16 @@ private constructor(
 
             class Builder {
 
-                private var defaultUnitAmount: JsonField<String> = JsonMissing.of()
-                private var dimensions: JsonField<List<String?>> = JsonMissing.of()
-                private var matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of()
+                private var defaultUnitAmount: JsonField<String>? = null
+                private var dimensions: JsonField<MutableList<String?>>? = null
+                private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(matrixConfig: MatrixConfig) = apply {
                     defaultUnitAmount = matrixConfig.defaultUnitAmount
-                    dimensions = matrixConfig.dimensions
-                    matrixValues = matrixConfig.matrixValues
+                    dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                    matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                     additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                 }
 
@@ -5988,7 +6403,21 @@ private constructor(
 
                 /** One or two event property values to evaluate matrix groups by */
                 fun dimensions(dimensions: JsonField<List<String?>>) = apply {
-                    this.dimensions = dimensions
+                    this.dimensions = dimensions.map { it.toMutableList() }
+                }
+
+                /** One or two event property values to evaluate matrix groups by */
+                fun addDimension(dimension: String) = apply {
+                    dimensions =
+                        (dimensions ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(dimension)
+                        }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
@@ -5997,7 +6426,21 @@ private constructor(
 
                 /** Matrix values for specified matrix grouping keys */
                 fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
-                    this.matrixValues = matrixValues
+                    this.matrixValues = matrixValues.map { it.toMutableList() }
+                }
+
+                /** Matrix values for specified matrix grouping keys */
+                fun addMatrixValue(matrixValue: MatrixValue) = apply {
+                    matrixValues =
+                        (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(matrixValue)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -6024,9 +6467,13 @@ private constructor(
 
                 fun build(): MatrixConfig =
                     MatrixConfig(
-                        defaultUnitAmount,
-                        dimensions.map { it.toImmutable() },
-                        matrixValues.map { it.toImmutable() },
+                        checkNotNull(defaultUnitAmount) {
+                            "`defaultUnitAmount` is required but was not set"
+                        },
+                        checkNotNull(dimensions) { "`dimensions` is required but was not set" }
+                            .map { it.toImmutable() },
+                        checkNotNull(matrixValues) { "`matrixValues` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6063,10 +6510,12 @@ private constructor(
                  */
                 @JsonProperty("dimension_values")
                 @ExcludeMissing
-                fun _dimensionValues() = dimensionValues
+                fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                 /** Unit price for the specified dimension_values */
-                @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -6091,13 +6540,13 @@ private constructor(
 
                 class Builder {
 
-                    private var dimensionValues: JsonField<List<String?>> = JsonMissing.of()
-                    private var unitAmount: JsonField<String> = JsonMissing.of()
+                    private var dimensionValues: JsonField<MutableList<String?>>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixValue: MatrixValue) = apply {
-                        dimensionValues = matrixValue.dimensionValues
+                        dimensionValues = matrixValue.dimensionValues.map { it.toMutableList() }
                         unitAmount = matrixValue.unitAmount
                         additionalProperties = matrixValue.additionalProperties.toMutableMap()
                     }
@@ -6116,7 +6565,25 @@ private constructor(
                      * an instance tier.
                      */
                     fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
-                        this.dimensionValues = dimensionValues
+                        this.dimensionValues = dimensionValues.map { it.toMutableList() }
+                    }
+
+                    /**
+                     * One or two matrix keys to filter usage to this Matrix value by. For example,
+                     * ["region", "tier"] could be used to filter cloud usage by a cloud region and
+                     * an instance tier.
+                     */
+                    fun addDimensionValue(dimensionValue: String) = apply {
+                        dimensionValues =
+                            (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimensionValue)
+                            }
                     }
 
                     /** Unit price for the specified dimension_values */
@@ -6151,8 +6618,11 @@ private constructor(
 
                     fun build(): MatrixValue =
                         MatrixValue(
-                            dimensionValues.map { it.toImmutable() },
-                            unitAmount,
+                            checkNotNull(dimensionValues) {
+                                    "`dimensionValues` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -6223,10 +6693,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -6251,13 +6723,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -6274,7 +6746,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -6310,8 +6799,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6447,10 +6941,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -6475,13 +6971,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -6498,7 +6994,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -6534,8 +7047,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6822,64 +7340,86 @@ private constructor(
 
         fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
-        @JsonProperty("tiered_config") @ExcludeMissing fun _tieredConfig() = tieredConfig
+        @JsonProperty("tiered_config")
+        @ExcludeMissing
+        fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6925,31 +7465,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredConfig: JsonField<TieredConfig> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredConfig: JsonField<TieredConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6984,8 +7522,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -7002,8 +7543,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -7015,8 +7562,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -7026,27 +7576,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -7056,11 +7634,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -7080,11 +7664,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -7098,7 +7688,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -7135,29 +7732,39 @@ private constructor(
 
             fun build(): TieredPrice =
                 TieredPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredConfig) { "`tieredConfig` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -7175,7 +7782,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7199,7 +7806,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7234,7 +7841,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -7273,9 +7884,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7300,8 +7913,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7347,8 +7960,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7527,9 +8140,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7554,8 +8169,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7600,8 +8215,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7642,9 +8259,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7669,8 +8288,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7717,8 +8336,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7816,9 +8435,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7843,8 +8462,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7886,8 +8505,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -7940,10 +8559,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -7968,13 +8589,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -7991,7 +8612,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -8027,8 +8665,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -8164,10 +8807,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -8192,13 +8837,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -8215,7 +8860,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -8251,8 +8913,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -8398,7 +9065,7 @@ private constructor(
             fun tiers(): List<Tier> = tiers.getRequired("tiers")
 
             /** Tiers for rating based on total usage quantities into the specified tier */
-            @JsonProperty("tiers") @ExcludeMissing fun _tiers() = tiers
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -8422,12 +9089,12 @@ private constructor(
 
             class Builder {
 
-                private var tiers: JsonField<List<Tier>> = JsonMissing.of()
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(tieredConfig: TieredConfig) = apply {
-                    tiers = tieredConfig.tiers
+                    tiers = tieredConfig.tiers.map { it.toMutableList() }
                     additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                 }
 
@@ -8435,7 +9102,23 @@ private constructor(
                 fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
 
                 /** Tiers for rating based on total usage quantities into the specified tier */
-                fun tiers(tiers: JsonField<List<Tier>>) = apply { this.tiers = tiers }
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
+
+                /** Tiers for rating based on total usage quantities into the specified tier */
+                fun addTier(tier: Tier) = apply {
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -8460,7 +9143,11 @@ private constructor(
                 }
 
                 fun build(): TieredConfig =
-                    TieredConfig(tiers.map { it.toImmutable() }, additionalProperties.toImmutable())
+                    TieredConfig(
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             @NoAutoDetect
@@ -8491,13 +9178,19 @@ private constructor(
                     Optional.ofNullable(lastUnit.getNullable("last_unit"))
 
                 /** Inclusive tier starting value */
-                @JsonProperty("first_unit") @ExcludeMissing fun _firstUnit() = firstUnit
+                @JsonProperty("first_unit")
+                @ExcludeMissing
+                fun _firstUnit(): JsonField<Double> = firstUnit
 
                 /** Amount per unit */
-                @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 /** Exclusive tier ending value. If null, this is treated as the last tier */
-                @JsonProperty("last_unit") @ExcludeMissing fun _lastUnit() = lastUnit
+                @JsonProperty("last_unit")
+                @ExcludeMissing
+                fun _lastUnit(): JsonField<Double> = lastUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -8523,8 +9216,8 @@ private constructor(
 
                 class Builder {
 
-                    private var firstUnit: JsonField<Double> = JsonMissing.of()
-                    private var unitAmount: JsonField<String> = JsonMissing.of()
+                    private var firstUnit: JsonField<Double>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var lastUnit: JsonField<Double> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -8553,7 +9246,15 @@ private constructor(
                     }
 
                     /** Exclusive tier ending value. If null, this is treated as the last tier */
-                    fun lastUnit(lastUnit: Double) = lastUnit(JsonField.of(lastUnit))
+                    fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
+
+                    /** Exclusive tier ending value. If null, this is treated as the last tier */
+                    fun lastUnit(lastUnit: Double) = lastUnit(lastUnit as Double?)
+
+                    /** Exclusive tier ending value. If null, this is treated as the last tier */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun lastUnit(lastUnit: Optional<Double>) =
+                        lastUnit(lastUnit.orElse(null) as Double?)
 
                     /** Exclusive tier ending value. If null, this is treated as the last tier */
                     fun lastUnit(lastUnit: JsonField<Double>) = apply { this.lastUnit = lastUnit }
@@ -8582,8 +9283,8 @@ private constructor(
 
                     fun build(): Tier =
                         Tier(
-                            firstUnit,
-                            unitAmount,
+                            checkNotNull(firstUnit) { "`firstUnit` is required but was not set" },
+                            checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             lastUnit,
                             additionalProperties.toImmutable(),
                         )
@@ -8781,64 +9482,86 @@ private constructor(
 
         fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig.getRequired("tiered_bps_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
-        @JsonProperty("tiered_bps_config") @ExcludeMissing fun _tieredBpsConfig() = tieredBpsConfig
+        @JsonProperty("tiered_bps_config")
+        @ExcludeMissing
+        fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -8884,31 +9607,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -8943,8 +9664,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -8961,8 +9685,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -8974,8 +9704,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -8985,27 +9718,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -9015,11 +9776,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -9039,11 +9806,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -9057,7 +9830,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -9095,29 +9875,41 @@ private constructor(
 
             fun build(): TieredBpsPrice =
                 TieredBpsPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredBpsConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredBpsConfig) {
+                        "`tieredBpsConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -9135,7 +9927,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9159,7 +9951,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9194,7 +9986,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -9233,9 +10029,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9260,8 +10058,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9307,8 +10105,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -9487,9 +10285,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9514,8 +10314,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9560,8 +10360,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -9602,9 +10404,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9629,8 +10433,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9677,8 +10481,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -9776,9 +10580,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9803,8 +10607,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9846,8 +10650,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -9900,10 +10704,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -9928,13 +10734,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -9951,7 +10757,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -9987,8 +10810,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -10124,10 +10952,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -10152,13 +10982,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -10175,7 +11005,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -10211,8 +11058,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -10362,7 +11214,7 @@ private constructor(
             /**
              * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified tiers
              */
-            @JsonProperty("tiers") @ExcludeMissing fun _tiers() = tiers
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -10386,12 +11238,12 @@ private constructor(
 
             class Builder {
 
-                private var tiers: JsonField<List<Tier>> = JsonMissing.of()
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                    tiers = tieredBpsConfig.tiers
+                    tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                     additionalProperties = tieredBpsConfig.additionalProperties.toMutableMap()
                 }
 
@@ -10405,7 +11257,26 @@ private constructor(
                  * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
                  * tiers
                  */
-                fun tiers(tiers: JsonField<List<Tier>>) = apply { this.tiers = tiers }
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
+
+                /**
+                 * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
+                 * tiers
+                 */
+                fun addTier(tier: Tier) = apply {
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -10431,7 +11302,8 @@ private constructor(
 
                 fun build(): TieredBpsConfig =
                     TieredBpsConfig(
-                        tiers.map { it.toImmutable() },
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -10471,18 +11343,22 @@ private constructor(
                     Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
 
                 /** Per-event basis point rate */
-                @JsonProperty("bps") @ExcludeMissing fun _bps() = bps
+                @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                 /** Inclusive tier starting value */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** Exclusive tier ending value */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** Per unit maximum to charge */
                 @JsonProperty("per_unit_maximum")
                 @ExcludeMissing
-                fun _perUnitMaximum() = perUnitMaximum
+                fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -10509,8 +11385,8 @@ private constructor(
 
                 class Builder {
 
-                    private var bps: JsonField<Double> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
+                    private var bps: JsonField<Double>? = null
+                    private var minimumAmount: JsonField<String>? = null
                     private var maximumAmount: JsonField<String> = JsonMissing.of()
                     private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -10540,8 +11416,12 @@ private constructor(
                     }
 
                     /** Exclusive tier ending value */
-                    fun maximumAmount(maximumAmount: String) =
-                        maximumAmount(JsonField.of(maximumAmount))
+                    fun maximumAmount(maximumAmount: String?) =
+                        maximumAmount(JsonField.ofNullable(maximumAmount))
+
+                    /** Exclusive tier ending value */
+                    fun maximumAmount(maximumAmount: Optional<String>) =
+                        maximumAmount(maximumAmount.orElse(null))
 
                     /** Exclusive tier ending value */
                     fun maximumAmount(maximumAmount: JsonField<String>) = apply {
@@ -10549,8 +11429,12 @@ private constructor(
                     }
 
                     /** Per unit maximum to charge */
-                    fun perUnitMaximum(perUnitMaximum: String) =
-                        perUnitMaximum(JsonField.of(perUnitMaximum))
+                    fun perUnitMaximum(perUnitMaximum: String?) =
+                        perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
+                    /** Per unit maximum to charge */
+                    fun perUnitMaximum(perUnitMaximum: Optional<String>) =
+                        perUnitMaximum(perUnitMaximum.orElse(null))
 
                     /** Per unit maximum to charge */
                     fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
@@ -10581,8 +11465,10 @@ private constructor(
 
                     fun build(): Tier =
                         Tier(
-                            bps,
-                            minimumAmount,
+                            checkNotNull(bps) { "`bps` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
                             maximumAmount,
                             perUnitMaximum,
                             additionalProperties.toImmutable(),
@@ -10781,64 +11667,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("bps_config") @ExcludeMissing fun _bpsConfig() = bpsConfig
+        @JsonProperty("bps_config")
+        @ExcludeMissing
+        fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -10884,31 +11792,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var bpsConfig: JsonField<BpsConfig> = JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var bpsConfig: JsonField<BpsConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -10943,8 +11849,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -10965,8 +11874,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -10978,8 +11893,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -10989,27 +11907,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -11019,11 +11965,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -11043,11 +11995,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -11061,7 +12019,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -11092,29 +12057,39 @@ private constructor(
 
             fun build(): BpsPrice =
                 BpsPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    bpsConfig,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(bpsConfig) { "`bpsConfig` is required but was not set" },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -11132,7 +12107,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11156,7 +12131,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11191,7 +12166,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -11230,9 +12209,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11257,8 +12238,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11304,8 +12285,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -11407,10 +12388,12 @@ private constructor(
                 Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
 
             /** Basis point take rate per event */
-            @JsonProperty("bps") @ExcludeMissing fun _bps() = bps
+            @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
             /** Optional currency amount maximum to cap spend per event */
-            @JsonProperty("per_unit_maximum") @ExcludeMissing fun _perUnitMaximum() = perUnitMaximum
+            @JsonProperty("per_unit_maximum")
+            @ExcludeMissing
+            fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11435,7 +12418,7 @@ private constructor(
 
             class Builder {
 
-                private var bps: JsonField<Double> = JsonMissing.of()
+                private var bps: JsonField<Double>? = null
                 private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -11453,8 +12436,12 @@ private constructor(
                 fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                 /** Optional currency amount maximum to cap spend per event */
-                fun perUnitMaximum(perUnitMaximum: String) =
-                    perUnitMaximum(JsonField.of(perUnitMaximum))
+                fun perUnitMaximum(perUnitMaximum: String?) =
+                    perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
+                /** Optional currency amount maximum to cap spend per event */
+                fun perUnitMaximum(perUnitMaximum: Optional<String>) =
+                    perUnitMaximum(perUnitMaximum.orElse(null))
 
                 /** Optional currency amount maximum to cap spend per event */
                 fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
@@ -11485,7 +12472,7 @@ private constructor(
 
                 fun build(): BpsConfig =
                     BpsConfig(
-                        bps,
+                        checkNotNull(bps) { "`bps` is required but was not set" },
                         perUnitMaximum,
                         additionalProperties.toImmutable(),
                     )
@@ -11608,9 +12595,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11635,8 +12624,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11681,8 +12670,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -11723,9 +12714,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11750,8 +12743,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11798,8 +12791,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -11897,9 +12890,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -11924,8 +12917,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11967,8 +12960,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -12021,10 +13014,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -12049,13 +13044,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -12072,7 +13067,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -12108,8 +13120,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -12245,10 +13262,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -12273,13 +13292,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -12296,7 +13315,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -12332,8 +13368,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -12620,64 +13661,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("bulk_bps_config") @ExcludeMissing fun _bulkBpsConfig() = bulkBpsConfig
+        @JsonProperty("bulk_bps_config")
+        @ExcludeMissing
+        fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -12723,31 +13786,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -12782,8 +13843,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -12807,8 +13871,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -12820,8 +13890,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -12831,27 +13904,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -12861,11 +13962,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -12885,11 +13992,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -12903,7 +14016,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -12934,29 +14054,39 @@ private constructor(
 
             fun build(): BulkBpsPrice =
                 BulkBpsPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    bulkBpsConfig,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(bulkBpsConfig) { "`bulkBpsConfig` is required but was not set" },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -12974,7 +14104,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -12998,7 +14128,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13033,7 +14163,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -13072,9 +14206,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -13099,8 +14235,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13146,8 +14282,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -13248,7 +14384,7 @@ private constructor(
              * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
              * based on total volume
              */
-            @JsonProperty("tiers") @ExcludeMissing fun _tiers() = tiers
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -13272,12 +14408,12 @@ private constructor(
 
             class Builder {
 
-                private var tiers: JsonField<List<Tier>> = JsonMissing.of()
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                    tiers = bulkBpsConfig.tiers
+                    tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                     additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                 }
 
@@ -13291,7 +14427,26 @@ private constructor(
                  * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
                  * based on total volume
                  */
-                fun tiers(tiers: JsonField<List<Tier>>) = apply { this.tiers = tiers }
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
+
+                /**
+                 * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
+                 * based on total volume
+                 */
+                fun addTier(tier: Tier) = apply {
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -13317,7 +14472,8 @@ private constructor(
 
                 fun build(): BulkBpsConfig =
                     BulkBpsConfig(
-                        tiers.map { it.toImmutable() },
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -13351,15 +14507,17 @@ private constructor(
                     Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
 
                 /** Basis points to rate on */
-                @JsonProperty("bps") @ExcludeMissing fun _bps() = bps
+                @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                 /** Upper bound for tier */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The maximum amount to charge for any one event */
                 @JsonProperty("per_unit_maximum")
                 @ExcludeMissing
-                fun _perUnitMaximum() = perUnitMaximum
+                fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -13385,7 +14543,7 @@ private constructor(
 
                 class Builder {
 
-                    private var bps: JsonField<Double> = JsonMissing.of()
+                    private var bps: JsonField<Double>? = null
                     private var maximumAmount: JsonField<String> = JsonMissing.of()
                     private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -13405,8 +14563,12 @@ private constructor(
                     fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                     /** Upper bound for tier */
-                    fun maximumAmount(maximumAmount: String) =
-                        maximumAmount(JsonField.of(maximumAmount))
+                    fun maximumAmount(maximumAmount: String?) =
+                        maximumAmount(JsonField.ofNullable(maximumAmount))
+
+                    /** Upper bound for tier */
+                    fun maximumAmount(maximumAmount: Optional<String>) =
+                        maximumAmount(maximumAmount.orElse(null))
 
                     /** Upper bound for tier */
                     fun maximumAmount(maximumAmount: JsonField<String>) = apply {
@@ -13414,8 +14576,12 @@ private constructor(
                     }
 
                     /** The maximum amount to charge for any one event */
-                    fun perUnitMaximum(perUnitMaximum: String) =
-                        perUnitMaximum(JsonField.of(perUnitMaximum))
+                    fun perUnitMaximum(perUnitMaximum: String?) =
+                        perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
+                    /** The maximum amount to charge for any one event */
+                    fun perUnitMaximum(perUnitMaximum: Optional<String>) =
+                        perUnitMaximum(perUnitMaximum.orElse(null))
 
                     /** The maximum amount to charge for any one event */
                     fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
@@ -13446,7 +14612,7 @@ private constructor(
 
                     fun build(): Tier =
                         Tier(
-                            bps,
+                            checkNotNull(bps) { "`bps` is required but was not set" },
                             maximumAmount,
                             perUnitMaximum,
                             additionalProperties.toImmutable(),
@@ -13588,9 +14754,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -13615,8 +14783,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13661,8 +14829,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -13703,9 +14873,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -13730,8 +14902,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13778,8 +14950,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -13877,9 +15049,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -13904,8 +15076,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13947,8 +15119,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -14001,10 +15173,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -14029,13 +15203,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -14052,7 +15226,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -14088,8 +15279,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -14225,10 +15421,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -14253,13 +15451,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -14276,7 +15474,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -14312,8 +15527,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -14600,64 +15820,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("bulk_config") @ExcludeMissing fun _bulkConfig() = bulkConfig
+        @JsonProperty("bulk_config")
+        @ExcludeMissing
+        fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -14703,31 +15945,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var bulkConfig: JsonField<BulkConfig> = JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var bulkConfig: JsonField<BulkConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -14762,8 +16002,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -14786,8 +16029,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -14799,8 +16048,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -14810,27 +16062,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -14840,11 +16120,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -14864,11 +16150,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -14882,7 +16174,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -14913,29 +16212,39 @@ private constructor(
 
             fun build(): BulkPrice =
                 BulkPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    bulkConfig,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(bulkConfig) { "`bulkConfig` is required but was not set" },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -14953,7 +16262,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -14977,7 +16286,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15012,7 +16321,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -15051,9 +16364,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15078,8 +16393,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15125,8 +16440,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -15221,7 +16536,7 @@ private constructor(
             fun tiers(): List<Tier> = tiers.getRequired("tiers")
 
             /** Bulk tiers for rating based on total usage volume */
-            @JsonProperty("tiers") @ExcludeMissing fun _tiers() = tiers
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15245,12 +16560,12 @@ private constructor(
 
             class Builder {
 
-                private var tiers: JsonField<List<Tier>> = JsonMissing.of()
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(bulkConfig: BulkConfig) = apply {
-                    tiers = bulkConfig.tiers
+                    tiers = bulkConfig.tiers.map { it.toMutableList() }
                     additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                 }
 
@@ -15258,7 +16573,23 @@ private constructor(
                 fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
 
                 /** Bulk tiers for rating based on total usage volume */
-                fun tiers(tiers: JsonField<List<Tier>>) = apply { this.tiers = tiers }
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
+
+                /** Bulk tiers for rating based on total usage volume */
+                fun addTier(tier: Tier) = apply {
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -15283,7 +16614,11 @@ private constructor(
                 }
 
                 fun build(): BulkConfig =
-                    BulkConfig(tiers.map { it.toImmutable() }, additionalProperties.toImmutable())
+                    BulkConfig(
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             @NoAutoDetect
@@ -15308,10 +16643,14 @@ private constructor(
                     Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
 
                 /** Amount per unit */
-                @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 /** Upper bound for this tier */
-                @JsonProperty("maximum_units") @ExcludeMissing fun _maximumUnits() = maximumUnits
+                @JsonProperty("maximum_units")
+                @ExcludeMissing
+                fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -15336,7 +16675,7 @@ private constructor(
 
                 class Builder {
 
-                    private var unitAmount: JsonField<String> = JsonMissing.of()
+                    private var unitAmount: JsonField<String>? = null
                     private var maximumUnits: JsonField<Double> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -15356,8 +16695,16 @@ private constructor(
                     }
 
                     /** Upper bound for this tier */
-                    fun maximumUnits(maximumUnits: Double) =
-                        maximumUnits(JsonField.of(maximumUnits))
+                    fun maximumUnits(maximumUnits: Double?) =
+                        maximumUnits(JsonField.ofNullable(maximumUnits))
+
+                    /** Upper bound for this tier */
+                    fun maximumUnits(maximumUnits: Double) = maximumUnits(maximumUnits as Double?)
+
+                    /** Upper bound for this tier */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun maximumUnits(maximumUnits: Optional<Double>) =
+                        maximumUnits(maximumUnits.orElse(null) as Double?)
 
                     /** Upper bound for this tier */
                     fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
@@ -15388,7 +16735,7 @@ private constructor(
 
                     fun build(): Tier =
                         Tier(
-                            unitAmount,
+                            checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             maximumUnits,
                             additionalProperties.toImmutable(),
                         )
@@ -15529,9 +16876,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15556,8 +16905,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15602,8 +16951,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -15644,9 +16995,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15671,8 +17024,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15719,8 +17072,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -15818,9 +17171,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15845,8 +17198,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15888,8 +17241,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -15942,10 +17295,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -15970,13 +17325,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -15993,7 +17348,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -16029,8 +17401,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -16166,10 +17543,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -16194,13 +17573,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -16217,7 +17596,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -16253,8 +17649,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -16543,66 +17944,87 @@ private constructor(
         fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
             thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("threshold_total_amount_config")
         @ExcludeMissing
-        fun _thresholdTotalAmountConfig() = thresholdTotalAmountConfig
+        fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
+            thresholdTotalAmountConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -16648,32 +18070,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
-                JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -16708,8 +18127,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -16726,8 +18148,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -16739,8 +18167,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -16750,27 +18181,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -16780,11 +18239,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -16804,11 +18269,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -16822,7 +18293,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -16860,29 +18338,41 @@ private constructor(
 
             fun build(): ThresholdTotalAmountPrice =
                 ThresholdTotalAmountPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    thresholdTotalAmountConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(thresholdTotalAmountConfig) {
+                        "`thresholdTotalAmountConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -16900,7 +18390,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -16924,7 +18414,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -16959,7 +18449,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -16998,9 +18492,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17025,8 +18521,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17072,8 +18568,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -17252,9 +18748,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17279,8 +18777,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17325,8 +18823,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -17367,9 +18867,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17394,8 +18896,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17442,8 +18944,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -17541,9 +19043,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17568,8 +19070,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17611,8 +19113,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -17665,10 +19167,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17693,13 +19197,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -17716,7 +19220,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -17752,8 +19273,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -17889,10 +19415,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -17917,13 +19445,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -17940,7 +19468,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -17976,8 +19521,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -18346,66 +19896,86 @@ private constructor(
         fun tieredPackageConfig(): TieredPackageConfig =
             tieredPackageConfig.getRequired("tiered_package_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("tiered_package_config")
         @ExcludeMissing
-        fun _tieredPackageConfig() = tieredPackageConfig
+        fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -18451,31 +20021,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -18510,8 +20078,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -18528,8 +20099,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -18541,8 +20118,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -18552,27 +20132,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -18582,11 +20190,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -18606,11 +20220,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -18624,7 +20244,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -18662,29 +20289,41 @@ private constructor(
 
             fun build(): TieredPackagePrice =
                 TieredPackagePrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredPackageConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredPackageConfig) {
+                        "`tieredPackageConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -18702,7 +20341,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -18726,7 +20365,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18761,7 +20400,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -18800,9 +20443,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -18827,8 +20472,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18874,8 +20519,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -19054,9 +20699,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -19081,8 +20728,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19127,8 +20774,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -19169,9 +20818,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -19196,8 +20847,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19244,8 +20895,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -19343,9 +20994,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -19370,8 +21021,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19413,8 +21064,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -19467,10 +21118,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -19495,13 +21148,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -19518,7 +21171,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -19554,8 +21224,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -19691,10 +21366,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -19719,13 +21396,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -19742,7 +21419,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -19778,8 +21472,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -20147,66 +21846,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("grouped_tiered_config")
         @ExcludeMissing
-        fun _groupedTieredConfig() = groupedTieredConfig
+        fun _groupedTieredConfig(): JsonField<GroupedTieredConfig> = groupedTieredConfig
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -20252,31 +21971,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var groupedTieredConfig: JsonField<GroupedTieredConfig> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var groupedTieredConfig: JsonField<GroupedTieredConfig>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -20311,8 +22028,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -20329,8 +22049,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -20342,8 +22068,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -20353,19 +22082,43 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
@@ -20379,8 +22132,12 @@ private constructor(
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -20390,11 +22147,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -20414,11 +22177,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -20432,7 +22201,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -20463,29 +22239,41 @@ private constructor(
 
             fun build(): GroupedTieredPrice =
                 GroupedTieredPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    groupedTieredConfig,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(groupedTieredConfig) {
+                        "`groupedTieredConfig` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -20503,7 +22291,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -20527,7 +22315,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20562,7 +22350,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -20601,9 +22393,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -20628,8 +22422,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20675,8 +22469,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -20855,9 +22649,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -20882,8 +22678,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20928,8 +22724,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -21050,9 +22848,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -21077,8 +22877,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21125,8 +22925,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -21224,9 +23024,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -21251,8 +23051,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21294,8 +23094,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -21348,10 +23148,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -21376,13 +23178,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -21399,7 +23201,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -21435,8 +23254,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -21572,10 +23396,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -21600,13 +23426,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -21623,7 +23449,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -21659,8 +23502,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -21948,66 +23796,86 @@ private constructor(
         fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
             tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("tiered_with_minimum_config")
         @ExcludeMissing
-        fun _tieredWithMinimumConfig() = tieredWithMinimumConfig
+        fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> = tieredWithMinimumConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -22053,32 +23921,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
-                JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -22113,8 +23978,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -22131,8 +23999,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -22144,8 +24018,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -22155,27 +24032,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -22185,11 +24090,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -22209,11 +24120,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -22227,7 +24144,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -22265,29 +24189,41 @@ private constructor(
 
             fun build(): TieredWithMinimumPrice =
                 TieredWithMinimumPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredWithMinimumConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredWithMinimumConfig) {
+                        "`tieredWithMinimumConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -22305,7 +24241,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -22329,7 +24265,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22364,7 +24300,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -22403,9 +24343,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -22430,8 +24372,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22477,8 +24419,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -22657,9 +24599,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -22684,8 +24628,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22730,8 +24674,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -22772,9 +24718,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -22799,8 +24747,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22847,8 +24795,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -22946,9 +24894,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -22973,8 +24921,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -23016,8 +24964,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -23070,10 +25018,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -23098,13 +25048,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -23121,7 +25071,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -23157,8 +25124,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -23294,10 +25266,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -23322,13 +25296,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -23345,7 +25319,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -23381,8 +25372,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -23752,66 +25748,87 @@ private constructor(
         fun tieredPackageWithMinimumConfig(): TieredPackageWithMinimumConfig =
             tieredPackageWithMinimumConfig.getRequired("tiered_package_with_minimum_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("tiered_package_with_minimum_config")
         @ExcludeMissing
-        fun _tieredPackageWithMinimumConfig() = tieredPackageWithMinimumConfig
+        fun _tieredPackageWithMinimumConfig(): JsonField<TieredPackageWithMinimumConfig> =
+            tieredPackageWithMinimumConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -23857,32 +25874,30 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig> =
-                JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig>? =
+                null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -23922,8 +25937,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -23940,8 +25958,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -23953,8 +25977,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -23964,27 +25991,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -23994,11 +26049,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -24018,11 +26079,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -24036,7 +26103,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -24075,29 +26149,41 @@ private constructor(
 
             fun build(): TieredPackageWithMinimumPrice =
                 TieredPackageWithMinimumPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredPackageWithMinimumConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredPackageWithMinimumConfig) {
+                        "`tieredPackageWithMinimumConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -24115,7 +26201,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24139,7 +26225,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24174,7 +26260,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -24213,9 +26303,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24240,8 +26332,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24287,8 +26379,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -24467,9 +26559,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24494,8 +26588,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24540,8 +26634,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -24582,9 +26678,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24609,8 +26707,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24657,8 +26755,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -24756,9 +26854,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24783,8 +26881,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24826,8 +26924,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -24880,10 +26978,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -24908,13 +27008,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -24931,7 +27031,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -24967,8 +27084,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -25104,10 +27226,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -25132,13 +27256,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -25155,7 +27279,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -25191,8 +27332,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -25563,66 +27709,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("package_with_allocation_config")
         @ExcludeMissing
-        fun _packageWithAllocationConfig() = packageWithAllocationConfig
+        fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
+            packageWithAllocationConfig
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -25668,32 +27835,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
-                JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -25729,8 +27893,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -25747,8 +27914,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -25760,8 +27933,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -25771,27 +27947,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -25801,11 +28005,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -25825,11 +28035,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -25851,7 +28067,14 @@ private constructor(
                 packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
             ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -25882,29 +28105,41 @@ private constructor(
 
             fun build(): PackageWithAllocationPrice =
                 PackageWithAllocationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    packageWithAllocationConfig,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(packageWithAllocationConfig) {
+                        "`packageWithAllocationConfig` is required but was not set"
+                    },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -25922,7 +28157,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -25946,7 +28181,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -25981,7 +28216,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -26020,9 +28259,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26047,8 +28288,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26094,8 +28335,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -26274,9 +28515,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26301,8 +28544,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26347,8 +28590,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -26389,9 +28634,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26416,8 +28663,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26464,8 +28711,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -26563,9 +28810,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26590,8 +28837,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26633,8 +28880,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -26687,10 +28934,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26715,13 +28964,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -26738,7 +28987,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -26774,8 +29040,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -26911,10 +29182,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -26939,13 +29212,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -26962,7 +29235,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -26998,8 +29288,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -27369,66 +29664,86 @@ private constructor(
         fun unitWithPercentConfig(): UnitWithPercentConfig =
             unitWithPercentConfig.getRequired("unit_with_percent_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("unit_with_percent_config")
         @ExcludeMissing
-        fun _unitWithPercentConfig() = unitWithPercentConfig
+        fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> = unitWithPercentConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -27474,31 +29789,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var unitWithPercentConfig: JsonField<UnitWithPercentConfig> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -27533,8 +29846,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -27551,8 +29867,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -27564,8 +29886,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -27575,27 +29900,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -27605,11 +29958,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -27629,11 +29988,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -27647,7 +30012,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -27686,29 +30058,41 @@ private constructor(
 
             fun build(): UnitWithPercentPrice =
                 UnitWithPercentPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    unitWithPercentConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(unitWithPercentConfig) {
+                        "`unitWithPercentConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -27726,7 +30110,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -27750,7 +30134,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -27785,7 +30169,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -27824,9 +30212,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -27851,8 +30241,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -27898,8 +30288,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -28078,9 +30468,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -28105,8 +30497,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -28151,8 +30543,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -28193,9 +30587,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -28220,8 +30616,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -28268,8 +30664,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -28367,9 +30763,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -28394,8 +30790,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -28437,8 +30833,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -28491,10 +30887,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -28519,13 +30917,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -28542,7 +30940,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -28578,8 +30993,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -28715,10 +31135,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -28743,13 +31165,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -28766,7 +31188,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -28802,8 +31241,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -29172,66 +31616,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
         @JsonProperty("matrix_with_allocation_config")
         @ExcludeMissing
-        fun _matrixWithAllocationConfig() = matrixWithAllocationConfig
+        fun _matrixWithAllocationConfig(): JsonField<MatrixWithAllocationConfig> =
+            matrixWithAllocationConfig
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -29277,32 +31742,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig> =
-                JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -29337,8 +31799,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -29355,8 +31820,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -29368,8 +31839,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -29379,27 +31853,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -29416,11 +31918,17 @@ private constructor(
                 matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>
             ) = apply { this.matrixWithAllocationConfig = matrixWithAllocationConfig }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -29440,11 +31948,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -29458,7 +31972,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -29489,29 +32010,41 @@ private constructor(
 
             fun build(): MatrixWithAllocationPrice =
                 MatrixWithAllocationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    matrixWithAllocationConfig,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(matrixWithAllocationConfig) {
+                        "`matrixWithAllocationConfig` is required but was not set"
+                    },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -29529,7 +32062,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -29553,7 +32086,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -29588,7 +32121,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -29627,9 +32164,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -29654,8 +32193,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -29701,8 +32240,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -29881,9 +32420,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -29908,8 +32449,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -29954,8 +32495,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -29996,9 +32539,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -30023,8 +32568,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -30071,8 +32616,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -30170,9 +32715,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -30197,8 +32742,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -30240,8 +32785,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -30297,18 +32842,24 @@ private constructor(
             fun matrixValues(): List<MatrixValue> = matrixValues.getRequired("matrix_values")
 
             /** Allocation to be used to calculate the price */
-            @JsonProperty("allocation") @ExcludeMissing fun _allocation() = allocation
+            @JsonProperty("allocation")
+            @ExcludeMissing
+            fun _allocation(): JsonField<Double> = allocation
 
             /** Default per unit rate for any usage not bucketed into a specified matrix_value */
             @JsonProperty("default_unit_amount")
             @ExcludeMissing
-            fun _defaultUnitAmount() = defaultUnitAmount
+            fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
             /** One or two event property values to evaluate matrix groups by */
-            @JsonProperty("dimensions") @ExcludeMissing fun _dimensions() = dimensions
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            fun _dimensions(): JsonField<List<String?>> = dimensions
 
             /** Matrix values for specified matrix grouping keys */
-            @JsonProperty("matrix_values") @ExcludeMissing fun _matrixValues() = matrixValues
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -30335,18 +32886,19 @@ private constructor(
 
             class Builder {
 
-                private var allocation: JsonField<Double> = JsonMissing.of()
-                private var defaultUnitAmount: JsonField<String> = JsonMissing.of()
-                private var dimensions: JsonField<List<String?>> = JsonMissing.of()
-                private var matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of()
+                private var allocation: JsonField<Double>? = null
+                private var defaultUnitAmount: JsonField<String>? = null
+                private var dimensions: JsonField<MutableList<String?>>? = null
+                private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(matrixWithAllocationConfig: MatrixWithAllocationConfig) = apply {
                     allocation = matrixWithAllocationConfig.allocation
                     defaultUnitAmount = matrixWithAllocationConfig.defaultUnitAmount
-                    dimensions = matrixWithAllocationConfig.dimensions
-                    matrixValues = matrixWithAllocationConfig.matrixValues
+                    dimensions = matrixWithAllocationConfig.dimensions.map { it.toMutableList() }
+                    matrixValues =
+                        matrixWithAllocationConfig.matrixValues.map { it.toMutableList() }
                     additionalProperties =
                         matrixWithAllocationConfig.additionalProperties.toMutableMap()
                 }
@@ -30377,7 +32929,21 @@ private constructor(
 
                 /** One or two event property values to evaluate matrix groups by */
                 fun dimensions(dimensions: JsonField<List<String?>>) = apply {
-                    this.dimensions = dimensions
+                    this.dimensions = dimensions.map { it.toMutableList() }
+                }
+
+                /** One or two event property values to evaluate matrix groups by */
+                fun addDimension(dimension: String) = apply {
+                    dimensions =
+                        (dimensions ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(dimension)
+                        }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
@@ -30386,7 +32952,21 @@ private constructor(
 
                 /** Matrix values for specified matrix grouping keys */
                 fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
-                    this.matrixValues = matrixValues
+                    this.matrixValues = matrixValues.map { it.toMutableList() }
+                }
+
+                /** Matrix values for specified matrix grouping keys */
+                fun addMatrixValue(matrixValue: MatrixValue) = apply {
+                    matrixValues =
+                        (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(matrixValue)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -30413,10 +32993,14 @@ private constructor(
 
                 fun build(): MatrixWithAllocationConfig =
                     MatrixWithAllocationConfig(
-                        allocation,
-                        defaultUnitAmount,
-                        dimensions.map { it.toImmutable() },
-                        matrixValues.map { it.toImmutable() },
+                        checkNotNull(allocation) { "`allocation` is required but was not set" },
+                        checkNotNull(defaultUnitAmount) {
+                            "`defaultUnitAmount` is required but was not set"
+                        },
+                        checkNotNull(dimensions) { "`dimensions` is required but was not set" }
+                            .map { it.toImmutable() },
+                        checkNotNull(matrixValues) { "`matrixValues` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -30453,10 +33037,12 @@ private constructor(
                  */
                 @JsonProperty("dimension_values")
                 @ExcludeMissing
-                fun _dimensionValues() = dimensionValues
+                fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                 /** Unit price for the specified dimension_values */
-                @JsonProperty("unit_amount") @ExcludeMissing fun _unitAmount() = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -30481,13 +33067,13 @@ private constructor(
 
                 class Builder {
 
-                    private var dimensionValues: JsonField<List<String?>> = JsonMissing.of()
-                    private var unitAmount: JsonField<String> = JsonMissing.of()
+                    private var dimensionValues: JsonField<MutableList<String?>>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixValue: MatrixValue) = apply {
-                        dimensionValues = matrixValue.dimensionValues
+                        dimensionValues = matrixValue.dimensionValues.map { it.toMutableList() }
                         unitAmount = matrixValue.unitAmount
                         additionalProperties = matrixValue.additionalProperties.toMutableMap()
                     }
@@ -30506,7 +33092,25 @@ private constructor(
                      * an instance tier.
                      */
                     fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
-                        this.dimensionValues = dimensionValues
+                        this.dimensionValues = dimensionValues.map { it.toMutableList() }
+                    }
+
+                    /**
+                     * One or two matrix keys to filter usage to this Matrix value by. For example,
+                     * ["region", "tier"] could be used to filter cloud usage by a cloud region and
+                     * an instance tier.
+                     */
+                    fun addDimensionValue(dimensionValue: String) = apply {
+                        dimensionValues =
+                            (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimensionValue)
+                            }
                     }
 
                     /** Unit price for the specified dimension_values */
@@ -30541,8 +33145,11 @@ private constructor(
 
                     fun build(): MatrixValue =
                         MatrixValue(
-                            dimensionValues.map { it.toImmutable() },
-                            unitAmount,
+                            checkNotNull(dimensionValues) {
+                                    "`dimensionValues` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -30613,10 +33220,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -30641,13 +33250,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -30664,7 +33273,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -30700,8 +33326,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -30837,10 +33468,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -30865,13 +33498,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -30888,7 +33521,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -30924,8 +33574,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -31214,66 +33869,87 @@ private constructor(
         fun tieredWithProrationConfig(): TieredWithProrationConfig =
             tieredWithProrationConfig.getRequired("tiered_with_proration_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("tiered_with_proration_config")
         @ExcludeMissing
-        fun _tieredWithProrationConfig() = tieredWithProrationConfig
+        fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
+            tieredWithProrationConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -31319,32 +33995,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
-                JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -31379,8 +34052,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -31397,8 +34073,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -31410,8 +34092,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -31421,27 +34106,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -31451,11 +34164,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -31475,11 +34194,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -31493,7 +34218,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -31531,29 +34263,41 @@ private constructor(
 
             fun build(): TieredWithProrationPrice =
                 TieredWithProrationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    tieredWithProrationConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(tieredWithProrationConfig) {
+                        "`tieredWithProrationConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -31571,7 +34315,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -31595,7 +34339,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -31630,7 +34374,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -31669,9 +34417,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -31696,8 +34446,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -31743,8 +34493,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -31923,9 +34673,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -31950,8 +34702,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -31996,8 +34748,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -32038,9 +34792,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -32065,8 +34821,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -32113,8 +34869,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -32212,9 +34968,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -32239,8 +34995,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -32282,8 +35038,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -32336,10 +35092,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -32364,13 +35122,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -32387,7 +35145,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -32423,8 +35198,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -32560,10 +35340,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -32588,13 +35370,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -32611,7 +35393,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -32647,8 +35446,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -33017,66 +35821,86 @@ private constructor(
         fun unitWithProrationConfig(): UnitWithProrationConfig =
             unitWithProrationConfig.getRequired("unit_with_proration_config")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonProperty("unit_with_proration_config")
         @ExcludeMissing
-        fun _unitWithProrationConfig() = unitWithProrationConfig
+        fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> = unitWithProrationConfig
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -33122,32 +35946,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
-            private var unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
-                JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
+            private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -33182,8 +36003,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -33200,8 +36024,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -33213,8 +36043,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -33224,27 +36057,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -33254,11 +36115,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -33278,11 +36145,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -33296,7 +36169,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -33334,29 +36214,41 @@ private constructor(
 
             fun build(): UnitWithProrationPrice =
                 UnitWithProrationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
-                    unitWithProrationConfig,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
+                    checkNotNull(unitWithProrationConfig) {
+                        "`unitWithProrationConfig` is required but was not set"
+                    },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -33374,7 +36266,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -33398,7 +36290,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -33433,7 +36325,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -33472,9 +36368,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -33499,8 +36397,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -33546,8 +36444,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -33726,9 +36624,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -33753,8 +36653,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -33799,8 +36699,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -33841,9 +36743,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -33868,8 +36772,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -33916,8 +36820,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -34015,9 +36919,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -34042,8 +36946,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -34085,8 +36989,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -34139,10 +37043,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -34167,13 +37073,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -34190,7 +37096,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -34226,8 +37149,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -34363,10 +37291,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -34391,13 +37321,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -34414,7 +37344,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -34450,8 +37397,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -34820,66 +37772,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("grouped_allocation_config")
         @ExcludeMissing
-        fun _groupedAllocationConfig() = groupedAllocationConfig
+        fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> = groupedAllocationConfig
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -34925,32 +37897,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
-                JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -34985,8 +37954,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -35003,8 +37975,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -35016,8 +37994,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -35027,19 +38008,43 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
@@ -35053,8 +38058,12 @@ private constructor(
             ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -35064,11 +38073,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -35088,11 +38103,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -35106,7 +38127,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -35137,29 +38165,41 @@ private constructor(
 
             fun build(): GroupedAllocationPrice =
                 GroupedAllocationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    groupedAllocationConfig,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(groupedAllocationConfig) {
+                        "`groupedAllocationConfig` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -35177,7 +38217,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -35201,7 +38241,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -35236,7 +38276,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -35275,9 +38319,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -35302,8 +38348,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -35349,8 +38395,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -35529,9 +38575,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -35556,8 +38604,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -35602,8 +38650,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -35725,9 +38775,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -35752,8 +38804,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -35800,8 +38852,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -35899,9 +38951,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -35926,8 +38978,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -35969,8 +39021,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -36023,10 +39075,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -36051,13 +39105,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -36074,7 +39128,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -36110,8 +39181,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -36247,10 +39323,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -36275,13 +39353,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -36298,7 +39376,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -36334,8 +39429,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -36624,66 +39724,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("grouped_with_prorated_minimum_config")
         @ExcludeMissing
-        fun _groupedWithProratedMinimumConfig() = groupedWithProratedMinimumConfig
+        fun _groupedWithProratedMinimumConfig(): JsonField<GroupedWithProratedMinimumConfig> =
+            groupedWithProratedMinimumConfig
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -36729,33 +39850,31 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
             private var groupedWithProratedMinimumConfig:
-                JsonField<GroupedWithProratedMinimumConfig> =
-                JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+                JsonField<GroupedWithProratedMinimumConfig>? =
+                null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -36795,8 +39914,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -36813,8 +39935,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -36826,8 +39954,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -36837,19 +39968,43 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
@@ -36864,8 +40019,12 @@ private constructor(
             ) = apply { this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -36875,11 +40034,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -36899,11 +40064,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -36917,7 +40088,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -36948,29 +40126,41 @@ private constructor(
 
             fun build(): GroupedWithProratedMinimumPrice =
                 GroupedWithProratedMinimumPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    groupedWithProratedMinimumConfig,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(groupedWithProratedMinimumConfig) {
+                        "`groupedWithProratedMinimumConfig` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -36988,7 +40178,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37012,7 +40202,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -37047,7 +40237,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -37086,9 +40280,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37113,8 +40309,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -37160,8 +40356,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -37340,9 +40536,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37367,8 +40565,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -37413,8 +40611,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -37538,9 +40738,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37565,8 +40767,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -37613,8 +40815,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -37712,9 +40914,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37739,8 +40941,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -37782,8 +40984,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -37836,10 +41038,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -37864,13 +41068,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -37887,7 +41091,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -37923,8 +41144,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -38060,10 +41286,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -38088,13 +41316,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -38111,7 +41339,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -38147,8 +41392,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -38437,66 +41687,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("grouped_with_metered_minimum_config")
         @ExcludeMissing
-        fun _groupedWithMeteredMinimumConfig() = groupedWithMeteredMinimumConfig
+        fun _groupedWithMeteredMinimumConfig(): JsonField<GroupedWithMeteredMinimumConfig> =
+            groupedWithMeteredMinimumConfig
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -38542,33 +41813,31 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
             private var groupedWithMeteredMinimumConfig:
-                JsonField<GroupedWithMeteredMinimumConfig> =
-                JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+                JsonField<GroupedWithMeteredMinimumConfig>? =
+                null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -38608,8 +41877,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -38626,8 +41898,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -38639,8 +41917,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -38650,19 +41931,43 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
@@ -38677,8 +41982,12 @@ private constructor(
             ) = apply { this.groupedWithMeteredMinimumConfig = groupedWithMeteredMinimumConfig }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -38688,11 +41997,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -38712,11 +42027,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -38730,7 +42051,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -38761,29 +42089,41 @@ private constructor(
 
             fun build(): GroupedWithMeteredMinimumPrice =
                 GroupedWithMeteredMinimumPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    groupedWithMeteredMinimumConfig,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(groupedWithMeteredMinimumConfig) {
+                        "`groupedWithMeteredMinimumConfig` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -38801,7 +42141,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -38825,7 +42165,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -38860,7 +42200,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -38899,9 +42243,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -38926,8 +42272,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -38973,8 +42319,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -39153,9 +42499,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -39180,8 +42528,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -39226,8 +42574,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -39351,9 +42701,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -39378,8 +42730,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -39426,8 +42778,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -39525,9 +42877,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -39552,8 +42904,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -39595,8 +42947,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -39649,10 +43001,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -39677,13 +43031,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -39700,7 +43054,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -39736,8 +43107,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -39873,10 +43249,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -39901,13 +43279,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -39924,7 +43302,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -39960,8 +43355,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -40250,66 +43650,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
         @JsonProperty("matrix_with_display_name_config")
         @ExcludeMissing
-        fun _matrixWithDisplayNameConfig() = matrixWithDisplayNameConfig
+        fun _matrixWithDisplayNameConfig(): JsonField<MatrixWithDisplayNameConfig> =
+            matrixWithDisplayNameConfig
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -40355,32 +43776,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig> =
-                JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -40416,8 +43834,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -40434,8 +43855,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -40447,8 +43874,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -40458,27 +43888,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -40496,11 +43954,17 @@ private constructor(
                 matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>
             ) = apply { this.matrixWithDisplayNameConfig = matrixWithDisplayNameConfig }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -40520,11 +43984,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -40538,7 +44008,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -40569,29 +44046,41 @@ private constructor(
 
             fun build(): MatrixWithDisplayNamePrice =
                 MatrixWithDisplayNamePrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    matrixWithDisplayNameConfig,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(matrixWithDisplayNameConfig) {
+                        "`matrixWithDisplayNameConfig` is required but was not set"
+                    },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -40609,7 +44098,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -40633,7 +44122,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -40668,7 +44157,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -40707,9 +44200,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -40734,8 +44229,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -40781,8 +44276,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -40961,9 +44456,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -40988,8 +44485,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -41034,8 +44531,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -41076,9 +44575,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -41103,8 +44604,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -41151,8 +44652,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -41250,9 +44751,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -41277,8 +44778,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -41320,8 +44821,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -41456,10 +44957,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -41484,13 +44987,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -41507,7 +45010,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -41543,8 +45063,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -41680,10 +45205,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -41708,13 +45235,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -41731,7 +45258,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -41767,8 +45311,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -42056,66 +45605,86 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         @JsonProperty("bulk_with_proration_config")
         @ExcludeMissing
-        fun _bulkWithProrationConfig() = bulkWithProrationConfig
+        fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> = bulkWithProrationConfig
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -42161,32 +45730,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -42221,8 +45787,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -42246,8 +45815,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -42259,8 +45834,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -42270,27 +45848,55 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
             }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -42300,11 +45906,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -42324,11 +45936,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -42342,7 +45960,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -42373,29 +45998,41 @@ private constructor(
 
             fun build(): BulkWithProrationPrice =
                 BulkWithProrationPrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    bulkWithProrationConfig,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(bulkWithProrationConfig) {
+                        "`bulkWithProrationConfig` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -42413,7 +46050,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -42437,7 +46074,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -42472,7 +46109,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -42511,9 +46152,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -42538,8 +46181,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -42585,8 +46228,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -42846,9 +46489,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -42873,8 +46518,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -42919,8 +46564,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -42961,9 +46608,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -42988,8 +46637,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -43036,8 +46685,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -43135,9 +46784,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -43162,8 +46811,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -43205,8 +46854,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -43259,10 +46908,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -43287,13 +46938,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -43310,7 +46961,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -43346,8 +47014,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -43483,10 +47156,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -43511,13 +47186,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -43534,7 +47209,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -43570,8 +47262,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -43860,66 +47557,87 @@ private constructor(
 
         fun priceType(): PriceType = priceType.getRequired("price_type")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+        @JsonProperty("billable_metric")
+        @ExcludeMissing
+        fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
         @JsonProperty("billing_cycle_configuration")
         @ExcludeMissing
-        fun _billingCycleConfiguration() = billingCycleConfiguration
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
-        @JsonProperty("cadence") @ExcludeMissing fun _cadence() = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        @JsonProperty("conversion_rate") @ExcludeMissing fun _conversionRate() = conversionRate
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
-        @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+        @JsonProperty("created_at")
+        @ExcludeMissing
+        fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
         @JsonProperty("credit_allocation")
         @ExcludeMissing
-        fun _creditAllocation() = creditAllocation
+        fun _creditAllocation(): JsonField<CreditAllocation> = creditAllocation
 
-        @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        @JsonProperty("discount") @ExcludeMissing fun _discount() = discount
+        @JsonProperty("discount") @ExcludeMissing fun _discount(): JsonField<Discount> = discount
 
-        @JsonProperty("external_price_id") @ExcludeMissing fun _externalPriceId() = externalPriceId
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         @JsonProperty("fixed_price_quantity")
         @ExcludeMissing
-        fun _fixedPriceQuantity() = fixedPriceQuantity
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         @JsonProperty("grouped_tiered_package_config")
         @ExcludeMissing
-        fun _groupedTieredPackageConfig() = groupedTieredPackageConfig
+        fun _groupedTieredPackageConfig(): JsonField<GroupedTieredPackageConfig> =
+            groupedTieredPackageConfig
 
         @JsonProperty("invoicing_cycle_configuration")
         @ExcludeMissing
-        fun _invoicingCycleConfiguration() = invoicingCycleConfiguration
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
-        @JsonProperty("item") @ExcludeMissing fun _item() = item
+        @JsonProperty("item") @ExcludeMissing fun _item(): JsonField<Item> = item
 
-        @JsonProperty("maximum") @ExcludeMissing fun _maximum() = maximum
+        @JsonProperty("maximum") @ExcludeMissing fun _maximum(): JsonField<Maximum> = maximum
 
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * User specified key-value pairs for the resource. If not present, this defaults to an
          * empty dictionary. Individual keys can be removed by setting the value to `null`, and the
          * entire metadata mapping can be cleared by setting `metadata` to `null`.
          */
-        @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
-        @JsonProperty("minimum") @ExcludeMissing fun _minimum() = minimum
+        @JsonProperty("minimum") @ExcludeMissing fun _minimum(): JsonField<Minimum> = minimum
 
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
-        @JsonProperty("model_type") @ExcludeMissing fun _modelType() = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("plan_phase_order") @ExcludeMissing fun _planPhaseOrder() = planPhaseOrder
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
-        @JsonProperty("price_type") @ExcludeMissing fun _priceType() = priceType
+        @JsonProperty("price_type")
+        @ExcludeMissing
+        fun _priceType(): JsonField<PriceType> = priceType
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -43965,32 +47683,29 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
-                JsonMissing.of()
-            private var cadence: JsonField<Cadence> = JsonMissing.of()
-            private var conversionRate: JsonField<Double> = JsonMissing.of()
-            private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var creditAllocation: JsonField<CreditAllocation> = JsonMissing.of()
-            private var currency: JsonField<String> = JsonMissing.of()
-            private var discount: JsonField<Discount> = JsonMissing.of()
-            private var externalPriceId: JsonField<String> = JsonMissing.of()
-            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
-            private var groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig> =
-                JsonMissing.of()
-            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
-                JsonMissing.of()
-            private var item: JsonField<Item> = JsonMissing.of()
-            private var maximum: JsonField<Maximum> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var metadata: JsonField<Metadata> = JsonMissing.of()
-            private var minimum: JsonField<Minimum> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var modelType: JsonField<ModelType> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
-            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-            private var priceType: JsonField<PriceType> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billableMetric: JsonField<BillableMetric>? = null
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var conversionRate: JsonField<Double>? = null
+            private var createdAt: JsonField<OffsetDateTime>? = null
+            private var creditAllocation: JsonField<CreditAllocation>? = null
+            private var currency: JsonField<String>? = null
+            private var discount: JsonField<Discount>? = null
+            private var externalPriceId: JsonField<String>? = null
+            private var fixedPriceQuantity: JsonField<Double>? = null
+            private var groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>? = null
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>? = null
+            private var item: JsonField<Item>? = null
+            private var maximum: JsonField<Maximum>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var metadata: JsonField<Metadata>? = null
+            private var minimum: JsonField<Minimum>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var planPhaseOrder: JsonField<Long>? = null
+            private var priceType: JsonField<PriceType>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -44025,8 +47740,11 @@ private constructor(
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
-            fun billableMetric(billableMetric: BillableMetric) =
-                billableMetric(JsonField.of(billableMetric))
+            fun billableMetric(billableMetric: BillableMetric?) =
+                billableMetric(JsonField.ofNullable(billableMetric))
+
+            fun billableMetric(billableMetric: Optional<BillableMetric>) =
+                billableMetric(billableMetric.orElse(null))
 
             fun billableMetric(billableMetric: JsonField<BillableMetric>) = apply {
                 this.billableMetric = billableMetric
@@ -44043,8 +47761,14 @@ private constructor(
 
             fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
-            fun conversionRate(conversionRate: Double) =
-                conversionRate(JsonField.of(conversionRate))
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
+
+            fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun conversionRate(conversionRate: Optional<Double>) =
+                conversionRate(conversionRate.orElse(null) as Double?)
 
             fun conversionRate(conversionRate: JsonField<Double>) = apply {
                 this.conversionRate = conversionRate
@@ -44056,8 +47780,11 @@ private constructor(
                 this.createdAt = createdAt
             }
 
-            fun creditAllocation(creditAllocation: CreditAllocation) =
-                creditAllocation(JsonField.of(creditAllocation))
+            fun creditAllocation(creditAllocation: CreditAllocation?) =
+                creditAllocation(JsonField.ofNullable(creditAllocation))
+
+            fun creditAllocation(creditAllocation: Optional<CreditAllocation>) =
+                creditAllocation(creditAllocation.orElse(null))
 
             fun creditAllocation(creditAllocation: JsonField<CreditAllocation>) = apply {
                 this.creditAllocation = creditAllocation
@@ -44067,19 +47794,43 @@ private constructor(
 
             fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun discount(discount: Discount) = discount(JsonField.of(discount))
+            fun discount(discount: Discount?) = discount(JsonField.ofNullable(discount))
+
+            fun discount(discount: Optional<Discount>) = discount(discount.orElse(null))
 
             fun discount(discount: JsonField<Discount>) = apply { this.discount = discount }
 
-            fun externalPriceId(externalPriceId: String) =
-                externalPriceId(JsonField.of(externalPriceId))
+            fun discount(percentageDiscount: PercentageDiscount) =
+                discount(Discount.ofPercentageDiscount(percentageDiscount))
+
+            fun discount(trialDiscount: TrialDiscount) =
+                discount(Discount.ofTrialDiscount(trialDiscount))
+
+            fun discount(usageDiscount: Discount.UsageDiscount) =
+                discount(Discount.ofUsageDiscount(usageDiscount))
+
+            fun discount(amountDiscount: AmountDiscount) =
+                discount(Discount.ofAmountDiscount(amountDiscount))
+
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
+            fun externalPriceId(externalPriceId: Optional<String>) =
+                externalPriceId(externalPriceId.orElse(null))
 
             fun externalPriceId(externalPriceId: JsonField<String>) = apply {
                 this.externalPriceId = externalPriceId
             }
 
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
-                fixedPriceQuantity(JsonField.of(fixedPriceQuantity))
+                fixedPriceQuantity(fixedPriceQuantity as Double?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
+                fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
             fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
                 this.fixedPriceQuantity = fixedPriceQuantity
@@ -44093,8 +47844,12 @@ private constructor(
             ) = apply { this.groupedTieredPackageConfig = groupedTieredPackageConfig }
 
             fun invoicingCycleConfiguration(
-                invoicingCycleConfiguration: InvoicingCycleConfiguration
-            ) = invoicingCycleConfiguration(JsonField.of(invoicingCycleConfiguration))
+                invoicingCycleConfiguration: InvoicingCycleConfiguration?
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
+
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
+            ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
@@ -44104,11 +47859,17 @@ private constructor(
 
             fun item(item: JsonField<Item>) = apply { this.item = item }
 
-            fun maximum(maximum: Maximum) = maximum(JsonField.of(maximum))
+            fun maximum(maximum: Maximum?) = maximum(JsonField.ofNullable(maximum))
+
+            fun maximum(maximum: Optional<Maximum>) = maximum(maximum.orElse(null))
 
             fun maximum(maximum: JsonField<Maximum>) = apply { this.maximum = maximum }
 
-            fun maximumAmount(maximumAmount: String) = maximumAmount(JsonField.of(maximumAmount))
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
+
+            fun maximumAmount(maximumAmount: Optional<String>) =
+                maximumAmount(maximumAmount.orElse(null))
 
             fun maximumAmount(maximumAmount: JsonField<String>) = apply {
                 this.maximumAmount = maximumAmount
@@ -44128,11 +47889,17 @@ private constructor(
              */
             fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
 
-            fun minimum(minimum: Minimum) = minimum(JsonField.of(minimum))
+            fun minimum(minimum: Minimum?) = minimum(JsonField.ofNullable(minimum))
+
+            fun minimum(minimum: Optional<Minimum>) = minimum(minimum.orElse(null))
 
             fun minimum(minimum: JsonField<Minimum>) = apply { this.minimum = minimum }
 
-            fun minimumAmount(minimumAmount: String) = minimumAmount(JsonField.of(minimumAmount))
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
+
+            fun minimumAmount(minimumAmount: Optional<String>) =
+                minimumAmount(minimumAmount.orElse(null))
 
             fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                 this.minimumAmount = minimumAmount
@@ -44146,7 +47913,14 @@ private constructor(
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(JsonField.of(planPhaseOrder))
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
+            fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
+
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
             fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
                 this.planPhaseOrder = planPhaseOrder
@@ -44177,29 +47951,41 @@ private constructor(
 
             fun build(): GroupedTieredPackagePrice =
                 GroupedTieredPackagePrice(
-                    id,
-                    billableMetric,
-                    billingCycleConfiguration,
-                    cadence,
-                    conversionRate,
-                    createdAt,
-                    creditAllocation,
-                    currency,
-                    discount,
-                    externalPriceId,
-                    fixedPriceQuantity,
-                    groupedTieredPackageConfig,
-                    invoicingCycleConfiguration,
-                    item,
-                    maximum,
-                    maximumAmount,
-                    metadata,
-                    minimum,
-                    minimumAmount,
-                    modelType,
-                    name,
-                    planPhaseOrder,
-                    priceType,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billableMetric) { "`billableMetric` is required but was not set" },
+                    checkNotNull(billingCycleConfiguration) {
+                        "`billingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(cadence) { "`cadence` is required but was not set" },
+                    checkNotNull(conversionRate) { "`conversionRate` is required but was not set" },
+                    checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                    checkNotNull(creditAllocation) {
+                        "`creditAllocation` is required but was not set"
+                    },
+                    checkNotNull(currency) { "`currency` is required but was not set" },
+                    checkNotNull(discount) { "`discount` is required but was not set" },
+                    checkNotNull(externalPriceId) {
+                        "`externalPriceId` is required but was not set"
+                    },
+                    checkNotNull(fixedPriceQuantity) {
+                        "`fixedPriceQuantity` is required but was not set"
+                    },
+                    checkNotNull(groupedTieredPackageConfig) {
+                        "`groupedTieredPackageConfig` is required but was not set"
+                    },
+                    checkNotNull(invoicingCycleConfiguration) {
+                        "`invoicingCycleConfiguration` is required but was not set"
+                    },
+                    checkNotNull(item) { "`item` is required but was not set" },
+                    checkNotNull(maximum) { "`maximum` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(metadata) { "`metadata` is required but was not set" },
+                    checkNotNull(minimum) { "`minimum` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(modelType) { "`modelType` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
+                    checkNotNull(planPhaseOrder) { "`planPhaseOrder` is required but was not set" },
+                    checkNotNull(priceType) { "`priceType` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -44217,7 +48003,7 @@ private constructor(
 
             fun id(): String = id.getRequired("id")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -44241,7 +48027,7 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -44276,7 +48062,11 @@ private constructor(
                     keys.forEach(::removeAdditionalProperty)
                 }
 
-                fun build(): BillableMetric = BillableMetric(id, additionalProperties.toImmutable())
+                fun build(): BillableMetric =
+                    BillableMetric(
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        additionalProperties.toImmutable()
+                    )
             }
 
             override fun equals(other: Any?): Boolean {
@@ -44315,9 +48105,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -44342,8 +48134,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -44389,8 +48181,8 @@ private constructor(
 
                 fun build(): BillingCycleConfiguration =
                     BillingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -44569,9 +48361,11 @@ private constructor(
 
             fun currency(): String = currency.getRequired("currency")
 
-            @JsonProperty("allows_rollover") @ExcludeMissing fun _allowsRollover() = allowsRollover
+            @JsonProperty("allows_rollover")
+            @ExcludeMissing
+            fun _allowsRollover(): JsonField<Boolean> = allowsRollover
 
-            @JsonProperty("currency") @ExcludeMissing fun _currency() = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -44596,8 +48390,8 @@ private constructor(
 
             class Builder {
 
-                private var allowsRollover: JsonField<Boolean> = JsonMissing.of()
-                private var currency: JsonField<String> = JsonMissing.of()
+                private var allowsRollover: JsonField<Boolean>? = null
+                private var currency: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -44642,8 +48436,10 @@ private constructor(
 
                 fun build(): CreditAllocation =
                     CreditAllocation(
-                        allowsRollover,
-                        currency,
+                        checkNotNull(allowsRollover) {
+                            "`allowsRollover` is required but was not set"
+                        },
+                        checkNotNull(currency) { "`currency` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -44765,9 +48561,11 @@ private constructor(
 
             fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
 
-            @JsonProperty("duration") @ExcludeMissing fun _duration() = duration
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
-            @JsonProperty("duration_unit") @ExcludeMissing fun _durationUnit() = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -44792,8 +48590,8 @@ private constructor(
 
             class Builder {
 
-                private var duration: JsonField<Long> = JsonMissing.of()
-                private var durationUnit: JsonField<DurationUnit> = JsonMissing.of()
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -44840,8 +48638,8 @@ private constructor(
 
                 fun build(): InvoicingCycleConfiguration =
                     InvoicingCycleConfiguration(
-                        duration,
-                        durationUnit,
+                        checkNotNull(duration) { "`duration` is required but was not set" },
+                        checkNotNull(durationUnit) { "`durationUnit` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -44939,9 +48737,9 @@ private constructor(
 
             fun name(): String = name.getRequired("name")
 
-            @JsonProperty("id") @ExcludeMissing fun _id() = id
+            @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-            @JsonProperty("name") @ExcludeMissing fun _name() = name
+            @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -44966,8 +48764,8 @@ private constructor(
 
             class Builder {
 
-                private var id: JsonField<String> = JsonMissing.of()
-                private var name: JsonField<String> = JsonMissing.of()
+                private var id: JsonField<String>? = null
+                private var name: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -45009,8 +48807,8 @@ private constructor(
 
                 fun build(): Item =
                     Item(
-                        id,
-                        name,
+                        checkNotNull(id) { "`id` is required but was not set" },
+                        checkNotNull(name) { "`name` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -45063,10 +48861,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Maximum amount applied */
-            @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+            @JsonProperty("maximum_amount")
+            @ExcludeMissing
+            fun _maximumAmount(): JsonField<String> = maximumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -45091,13 +48891,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var maximumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var maximumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(maximum: Maximum) = apply {
-                    appliesToPriceIds = maximum.appliesToPriceIds
+                    appliesToPriceIds = maximum.appliesToPriceIds.map { it.toMutableList() }
                     maximumAmount = maximum.maximumAmount
                     additionalProperties = maximum.additionalProperties.toMutableMap()
                 }
@@ -45114,7 +48914,24 @@ private constructor(
                  * maximums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this maximum amount applies to. For plan/plan phase
+                 * maximums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Maximum amount applied */
@@ -45150,8 +48967,13 @@ private constructor(
 
                 fun build(): Maximum =
                     Maximum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        maximumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(maximumAmount) {
+                            "`maximumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -45287,10 +49109,12 @@ private constructor(
              */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** Minimum amount applied */
-            @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+            @JsonProperty("minimum_amount")
+            @ExcludeMissing
+            fun _minimumAmount(): JsonField<String> = minimumAmount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -45315,13 +49139,13 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var minimumAmount: JsonField<String> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var minimumAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(minimum: Minimum) = apply {
-                    appliesToPriceIds = minimum.appliesToPriceIds
+                    appliesToPriceIds = minimum.appliesToPriceIds.map { it.toMutableList() }
                     minimumAmount = minimum.minimumAmount
                     additionalProperties = minimum.additionalProperties.toMutableMap()
                 }
@@ -45338,7 +49162,24 @@ private constructor(
                  * minimums, this can be a subset of prices.
                  */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /**
+                 * List of price_ids that this minimum amount applies to. For plan/plan phase
+                 * minimums, this can be a subset of prices.
+                 */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** Minimum amount applied */
@@ -45374,8 +49215,13 @@ private constructor(
 
                 fun build(): Minimum =
                     Minimum(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        minimumAmount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(minimumAmount) {
+                            "`minimumAmount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceCreateParams.kt
index 12087044..1b63c225 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceCreateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,17 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint is used to create a [price](../reference/price). A price created using this
+ * endpoint is always an add-on, meaning that it’s not associated with a specific plan and can
+ * instead be individually added to subscriptions, including subscriptions on different plans.
+ *
+ * An `external_price_id` can be optionally specified as an alias to allow ergonomic interaction
+ * with prices in the Orb API.
+ *
+ * See the [Price resource](../reference/price) for the specification of different price model
+ * configurations possible in this endpoint.
+ */
 class PriceCreateParams
 constructor(
     private val body: PriceCreateBody,
@@ -1343,94 +1355,224 @@ constructor(
     class NewFloatingUnitPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("unit_config")
+        @ExcludeMissing
+        private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+        @JsonProperty("unit_config")
+        @ExcludeMissing
+        fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingUnitPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                unitConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1440,21 +1582,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var unitConfig: UnitConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var unitConfig: JsonField<UnitConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1478,27 +1622,44 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
 
-            fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+            fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                this.unitConfig = unitConfig
+            }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -1506,13 +1667,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -1529,13 +1696,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -1544,10 +1717,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -1557,21 +1736,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -1586,22 +1773,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -1611,12 +1809,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -1625,6 +1831,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1801,18 +2014,34 @@ constructor(
         class UnitConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("unit_amount") private val unitAmount: String,
+            @JsonProperty("unit_amount")
+            @ExcludeMissing
+            private val unitAmount: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Rate per unit of usage */
-            @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+            fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+            /** Rate per unit of usage */
+            @JsonProperty("unit_amount")
+            @ExcludeMissing
+            fun _unitAmount(): JsonField<String> = unitAmount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): UnitConfig = apply {
+                if (!validated) {
+                    unitAmount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1822,7 +2051,7 @@ constructor(
 
             class Builder {
 
-                private var unitAmount: String? = null
+                private var unitAmount: JsonField<String>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1832,7 +2061,12 @@ constructor(
                 }
 
                 /** Rate per unit of usage */
-                fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                /** Rate per unit of usage */
+                fun unitAmount(unitAmount: JsonField<String>) = apply {
+                    this.unitAmount = unitAmount
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -1886,22 +2120,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1911,8 +2167,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1924,10 +2180,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -2044,22 +2307,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2069,8 +2354,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2083,10 +2368,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -2212,6 +2504,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2292,132 +2592,264 @@ constructor(
     class NewFloatingPackagePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("package_config") private val packageConfig: PackageConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("package_config")
+        @ExcludeMissing
+        private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        fun itemId(): String = itemId.getRequired("item_id")
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        fun modelType(): ModelType = modelType.getRequired("model_type")
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
 
-        @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+        fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
-        @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
-        @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
-        @JsonProperty("billing_cycle_configuration")
         fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
-        @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
         /** An alias for the price. */
-        @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
-        @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
         /** The property used to group this price on an invoice */
-        @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
-        @JsonProperty("invoicing_cycle_configuration")
         fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
 
-        @JsonAnyGetter
-        @ExcludeMissing
-        fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
-        fun toBuilder() = Builder().from(this)
+        /** An ISO 4217 currency string for which this price is billed in. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
-        companion object {
+        /** The id of the item the plan will be associated with. */
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-            @JvmStatic fun builder() = Builder()
-        }
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
-        class Builder {
+        /** The name of the price. */
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var packageConfig: PackageConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
-            private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+        @JsonProperty("package_config")
+        @ExcludeMissing
+        fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
-            @JvmSynthetic
-            internal fun from(newFloatingPackagePrice: NewFloatingPackagePrice) = apply {
-                cadence = newFloatingPackagePrice.cadence
-                currency = newFloatingPackagePrice.currency
-                itemId = newFloatingPackagePrice.itemId
-                modelType = newFloatingPackagePrice.modelType
-                name = newFloatingPackagePrice.name
-                packageConfig = newFloatingPackagePrice.packageConfig
-                billableMetricId = newFloatingPackagePrice.billableMetricId
-                billedInAdvance = newFloatingPackagePrice.billedInAdvance
-                billingCycleConfiguration = newFloatingPackagePrice.billingCycleConfiguration
-                conversionRate = newFloatingPackagePrice.conversionRate
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        @JsonProperty("billing_cycle_configuration")
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
+
+        /** An alias for the price. */
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
+
+        /** The property used to group this price on an invoice */
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        @JsonProperty("invoicing_cycle_configuration")
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
+
+        @JsonAnyGetter
+        @ExcludeMissing
+        fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
+
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingPackagePrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                packageConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
+        fun toBuilder() = Builder().from(this)
+
+        companion object {
+
+            @JvmStatic fun builder() = Builder()
+        }
+
+        class Builder {
+
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var packageConfig: JsonField<PackageConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
+
+            @JvmSynthetic
+            internal fun from(newFloatingPackagePrice: NewFloatingPackagePrice) = apply {
+                cadence = newFloatingPackagePrice.cadence
+                currency = newFloatingPackagePrice.currency
+                itemId = newFloatingPackagePrice.itemId
+                modelType = newFloatingPackagePrice.modelType
+                name = newFloatingPackagePrice.name
+                packageConfig = newFloatingPackagePrice.packageConfig
+                billableMetricId = newFloatingPackagePrice.billableMetricId
+                billedInAdvance = newFloatingPackagePrice.billedInAdvance
+                billingCycleConfiguration = newFloatingPackagePrice.billingCycleConfiguration
+                conversionRate = newFloatingPackagePrice.conversionRate
                 externalPriceId = newFloatingPackagePrice.externalPriceId
                 fixedPriceQuantity = newFloatingPackagePrice.fixedPriceQuantity
                 invoiceGroupingKey = newFloatingPackagePrice.invoiceGroupingKey
@@ -2427,29 +2859,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun packageConfig(packageConfig: PackageConfig) =
+                packageConfig(JsonField.of(packageConfig))
 
-            fun packageConfig(packageConfig: PackageConfig) = apply {
+            fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                 this.packageConfig = packageConfig
             }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -2457,13 +2905,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -2480,13 +2934,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -2495,10 +2955,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -2508,21 +2974,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -2537,22 +3011,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -2562,12 +3047,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -2576,6 +3069,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -2752,25 +3252,52 @@ constructor(
         class PackageConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("package_amount") private val packageAmount: String,
-            @JsonProperty("package_size") private val packageSize: Long,
+            @JsonProperty("package_amount")
+            @ExcludeMissing
+            private val packageAmount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("package_size")
+            @ExcludeMissing
+            private val packageSize: JsonField<Long> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** A currency amount to rate usage by */
-            @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+            fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+            /**
+             * An integer amount to represent package size. For example, 1000 here would divide
+             * usage by 1000 before multiplying by package_amount in rating
+             */
+            fun packageSize(): Long = packageSize.getRequired("package_size")
+
+            /** A currency amount to rate usage by */
+            @JsonProperty("package_amount")
+            @ExcludeMissing
+            fun _packageAmount(): JsonField<String> = packageAmount
 
             /**
              * An integer amount to represent package size. For example, 1000 here would divide
              * usage by 1000 before multiplying by package_amount in rating
              */
-            @JsonProperty("package_size") fun packageSize(): Long = packageSize
+            @JsonProperty("package_size")
+            @ExcludeMissing
+            fun _packageSize(): JsonField<Long> = packageSize
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): PackageConfig = apply {
+                if (!validated) {
+                    packageAmount()
+                    packageSize()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2780,8 +3307,8 @@ constructor(
 
             class Builder {
 
-                private var packageAmount: String? = null
-                private var packageSize: Long? = null
+                private var packageAmount: JsonField<String>? = null
+                private var packageSize: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2792,7 +3319,11 @@ constructor(
                 }
 
                 /** A currency amount to rate usage by */
-                fun packageAmount(packageAmount: String) = apply {
+                fun packageAmount(packageAmount: String) =
+                    packageAmount(JsonField.of(packageAmount))
+
+                /** A currency amount to rate usage by */
+                fun packageAmount(packageAmount: JsonField<String>) = apply {
                     this.packageAmount = packageAmount
                 }
 
@@ -2800,7 +3331,15 @@ constructor(
                  * An integer amount to represent package size. For example, 1000 here would divide
                  * usage by 1000 before multiplying by package_amount in rating
                  */
-                fun packageSize(packageSize: Long) = apply { this.packageSize = packageSize }
+                fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                /**
+                 * An integer amount to represent package size. For example, 1000 here would divide
+                 * usage by 1000 before multiplying by package_amount in rating
+                 */
+                fun packageSize(packageSize: JsonField<Long>) = apply {
+                    this.packageSize = packageSize
+                }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -2857,22 +3396,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -2882,8 +3443,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -2895,10 +3456,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -3015,22 +3583,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3040,8 +3630,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3054,10 +3644,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -3183,6 +3780,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3263,94 +3868,224 @@ constructor(
     class NewFloatingMatrixPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("matrix_config")
+        @ExcludeMissing
+        private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        fun itemId(): String = itemId.getRequired("item_id")
 
-        @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+        fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        fun modelType(): ModelType = modelType.getRequired("model_type")
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+        /** The id of the item the plan will be associated with. */
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+        @JsonProperty("matrix_config")
+        @ExcludeMissing
+        fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
+
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
+
+        /** The name of the price. */
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingMatrixPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                matrixConfig().validate()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -3360,21 +4095,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var matrixConfig: MatrixConfig? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var matrixConfig: JsonField<MatrixConfig>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -3398,29 +4135,44 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun matrixConfig(matrixConfig: MatrixConfig) = matrixConfig(JsonField.of(matrixConfig))
 
-            fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+            fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                 this.matrixConfig = matrixConfig
             }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -3428,13 +4180,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -3451,13 +4209,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -3466,10 +4230,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -3479,21 +4249,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -3508,22 +4286,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -3533,12 +4322,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -3547,6 +4344,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -3672,26 +4476,58 @@ constructor(
         class MatrixConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-            @JsonProperty("dimensions") private val dimensions: List<String?>,
-            @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+            @JsonProperty("default_unit_amount")
+            @ExcludeMissing
+            private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Default per unit rate for any usage not bucketed into a specified matrix_value */
-            @JsonProperty("default_unit_amount") fun defaultUnitAmount(): String = defaultUnitAmount
+            fun defaultUnitAmount(): String = defaultUnitAmount.getRequired("default_unit_amount")
 
             /** One or two event property values to evaluate matrix groups by */
-            @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+            fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
 
             /** Matrix values for specified matrix grouping keys */
-            @JsonProperty("matrix_values") fun matrixValues(): List<MatrixValue> = matrixValues
+            fun matrixValues(): List<MatrixValue> = matrixValues.getRequired("matrix_values")
+
+            /** Default per unit rate for any usage not bucketed into a specified matrix_value */
+            @JsonProperty("default_unit_amount")
+            @ExcludeMissing
+            fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
+
+            /** One or two event property values to evaluate matrix groups by */
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            fun _dimensions(): JsonField<List<String?>> = dimensions
+
+            /** Matrix values for specified matrix grouping keys */
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): MatrixConfig = apply {
+                if (!validated) {
+                    defaultUnitAmount()
+                    dimensions()
+                    matrixValues().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3701,44 +4537,75 @@ constructor(
 
             class Builder {
 
-                private var defaultUnitAmount: String? = null
-                private var dimensions: MutableList<String?>? = null
-                private var matrixValues: MutableList<MatrixValue>? = null
+                private var defaultUnitAmount: JsonField<String>? = null
+                private var dimensions: JsonField<MutableList<String?>>? = null
+                private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(matrixConfig: MatrixConfig) = apply {
                     defaultUnitAmount = matrixConfig.defaultUnitAmount
-                    dimensions = matrixConfig.dimensions.toMutableList()
-                    matrixValues = matrixConfig.matrixValues.toMutableList()
+                    dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                    matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                     additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                 }
 
                 /**
                  * Default per unit rate for any usage not bucketed into a specified matrix_value
                  */
-                fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                fun defaultUnitAmount(defaultUnitAmount: String) =
+                    defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                /**
+                 * Default per unit rate for any usage not bucketed into a specified matrix_value
+                 */
+                fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                     this.defaultUnitAmount = defaultUnitAmount
                 }
 
                 /** One or two event property values to evaluate matrix groups by */
-                fun dimensions(dimensions: List<String?>) = apply {
-                    this.dimensions = dimensions.toMutableList()
+                fun dimensions(dimensions: List<String?>) = dimensions(JsonField.of(dimensions))
+
+                /** One or two event property values to evaluate matrix groups by */
+                fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                    this.dimensions = dimensions.map { it.toMutableList() }
                 }
 
                 /** One or two event property values to evaluate matrix groups by */
                 fun addDimension(dimension: String) = apply {
-                    dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                    dimensions =
+                        (dimensions ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(dimension)
+                        }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
-                fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                    this.matrixValues = matrixValues.toMutableList()
+                fun matrixValues(matrixValues: List<MatrixValue>) =
+                    matrixValues(JsonField.of(matrixValues))
+
+                /** Matrix values for specified matrix grouping keys */
+                fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                    this.matrixValues = matrixValues.map { it.toMutableList() }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
                 fun addMatrixValue(matrixValue: MatrixValue) = apply {
-                    matrixValues = (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                    matrixValues =
+                        (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(matrixValue)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -3769,9 +4636,9 @@ constructor(
                             "`defaultUnitAmount` is required but was not set"
                         },
                         checkNotNull(dimensions) { "`dimensions` is required but was not set" }
-                            .toImmutable(),
+                            .map { it.toImmutable() },
                         checkNotNull(matrixValues) { "`matrixValues` is required but was not set" }
-                            .toImmutable(),
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3780,27 +4647,55 @@ constructor(
             class MatrixValue
             @JsonCreator
             private constructor(
-                @JsonProperty("dimension_values") private val dimensionValues: List<String?>,
-                @JsonProperty("unit_amount") private val unitAmount: String,
+                @JsonProperty("dimension_values")
+                @ExcludeMissing
+                private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                private val unitAmount: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                /**
+                 * One or two matrix keys to filter usage to this Matrix value by. For example,
+                 * ["region", "tier"] could be used to filter cloud usage by a cloud region and an
+                 * instance tier.
+                 */
+                fun dimensionValues(): List<String?> =
+                    dimensionValues.getRequired("dimension_values")
+
+                /** Unit price for the specified dimension_values */
+                fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                 /**
                  * One or two matrix keys to filter usage to this Matrix value by. For example,
                  * ["region", "tier"] could be used to filter cloud usage by a cloud region and an
                  * instance tier.
                  */
                 @JsonProperty("dimension_values")
-                fun dimensionValues(): List<String?> = dimensionValues
+                @ExcludeMissing
+                fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                 /** Unit price for the specified dimension_values */
-                @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): MatrixValue = apply {
+                    if (!validated) {
+                        dimensionValues()
+                        unitAmount()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -3810,13 +4705,13 @@ constructor(
 
                 class Builder {
 
-                    private var dimensionValues: MutableList<String?>? = null
-                    private var unitAmount: String? = null
+                    private var dimensionValues: JsonField<MutableList<String?>>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixValue: MatrixValue) = apply {
-                        dimensionValues = matrixValue.dimensionValues.toMutableList()
+                        dimensionValues = matrixValue.dimensionValues.map { it.toMutableList() }
                         unitAmount = matrixValue.unitAmount
                         additionalProperties = matrixValue.additionalProperties.toMutableMap()
                     }
@@ -3826,8 +4721,16 @@ constructor(
                      * ["region", "tier"] could be used to filter cloud usage by a cloud region and
                      * an instance tier.
                      */
-                    fun dimensionValues(dimensionValues: List<String?>) = apply {
-                        this.dimensionValues = dimensionValues.toMutableList()
+                    fun dimensionValues(dimensionValues: List<String?>) =
+                        dimensionValues(JsonField.of(dimensionValues))
+
+                    /**
+                     * One or two matrix keys to filter usage to this Matrix value by. For example,
+                     * ["region", "tier"] could be used to filter cloud usage by a cloud region and
+                     * an instance tier.
+                     */
+                    fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                        this.dimensionValues = dimensionValues.map { it.toMutableList() }
                     }
 
                     /**
@@ -3837,11 +4740,24 @@ constructor(
                      */
                     fun addDimensionValue(dimensionValue: String) = apply {
                         dimensionValues =
-                            (dimensionValues ?: mutableListOf()).apply { add(dimensionValue) }
+                            (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimensionValue)
+                            }
                     }
 
                     /** Unit price for the specified dimension_values */
-                    fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                    fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                    /** Unit price for the specified dimension_values */
+                    fun unitAmount(unitAmount: JsonField<String>) = apply {
+                        this.unitAmount = unitAmount
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -3870,7 +4786,7 @@ constructor(
                             checkNotNull(dimensionValues) {
                                     "`dimensionValues` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
@@ -3968,22 +4884,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3993,8 +4931,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4006,10 +4944,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -4126,22 +5071,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -4151,8 +5118,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -4165,10 +5132,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -4294,6 +5268,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -4374,96 +5356,227 @@ constructor(
     class NewFloatingMatrixWithAllocationPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
         @JsonProperty("matrix_with_allocation_config")
-        private val matrixWithAllocationConfig: MatrixWithAllocationConfig,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig> =
+            JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun matrixWithAllocationConfig(): MatrixWithAllocationConfig =
+            matrixWithAllocationConfig.getRequired("matrix_with_allocation_config")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
         @JsonProperty("matrix_with_allocation_config")
-        fun matrixWithAllocationConfig(): MatrixWithAllocationConfig = matrixWithAllocationConfig
+        @ExcludeMissing
+        fun _matrixWithAllocationConfig(): JsonField<MatrixWithAllocationConfig> =
+            matrixWithAllocationConfig
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingMatrixWithAllocationPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                matrixWithAllocationConfig().validate()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -4473,21 +5586,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var matrixWithAllocationConfig: MatrixWithAllocationConfig? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4517,30 +5632,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
             fun matrixWithAllocationConfig(matrixWithAllocationConfig: MatrixWithAllocationConfig) =
-                apply {
-                    this.matrixWithAllocationConfig = matrixWithAllocationConfig
-                }
+                matrixWithAllocationConfig(JsonField.of(matrixWithAllocationConfig))
+
+            fun matrixWithAllocationConfig(
+                matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>
+            ) = apply { this.matrixWithAllocationConfig = matrixWithAllocationConfig }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -4548,13 +5678,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -4571,13 +5707,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -4586,10 +5728,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -4599,21 +5747,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -4628,22 +5784,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -4653,12 +5820,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -4667,6 +5842,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -4794,30 +5976,70 @@ constructor(
         class MatrixWithAllocationConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("allocation") private val allocation: Double,
-            @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-            @JsonProperty("dimensions") private val dimensions: List<String?>,
-            @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+            @JsonProperty("allocation")
+            @ExcludeMissing
+            private val allocation: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("default_unit_amount")
+            @ExcludeMissing
+            private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Allocation to be used to calculate the price */
-            @JsonProperty("allocation") fun allocation(): Double = allocation
+            fun allocation(): Double = allocation.getRequired("allocation")
+
+            /** Default per unit rate for any usage not bucketed into a specified matrix_value */
+            fun defaultUnitAmount(): String = defaultUnitAmount.getRequired("default_unit_amount")
+
+            /** One or two event property values to evaluate matrix groups by */
+            fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+            /** Matrix values for specified matrix grouping keys */
+            fun matrixValues(): List<MatrixValue> = matrixValues.getRequired("matrix_values")
+
+            /** Allocation to be used to calculate the price */
+            @JsonProperty("allocation")
+            @ExcludeMissing
+            fun _allocation(): JsonField<Double> = allocation
 
             /** Default per unit rate for any usage not bucketed into a specified matrix_value */
-            @JsonProperty("default_unit_amount") fun defaultUnitAmount(): String = defaultUnitAmount
+            @JsonProperty("default_unit_amount")
+            @ExcludeMissing
+            fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
             /** One or two event property values to evaluate matrix groups by */
-            @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+            @JsonProperty("dimensions")
+            @ExcludeMissing
+            fun _dimensions(): JsonField<List<String?>> = dimensions
 
             /** Matrix values for specified matrix grouping keys */
-            @JsonProperty("matrix_values") fun matrixValues(): List<MatrixValue> = matrixValues
+            @JsonProperty("matrix_values")
+            @ExcludeMissing
+            fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): MatrixWithAllocationConfig = apply {
+                if (!validated) {
+                    allocation()
+                    defaultUnitAmount()
+                    dimensions()
+                    matrixValues().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -4827,50 +6049,87 @@ constructor(
 
             class Builder {
 
-                private var allocation: Double? = null
-                private var defaultUnitAmount: String? = null
-                private var dimensions: MutableList<String?>? = null
-                private var matrixValues: MutableList<MatrixValue>? = null
+                private var allocation: JsonField<Double>? = null
+                private var defaultUnitAmount: JsonField<String>? = null
+                private var dimensions: JsonField<MutableList<String?>>? = null
+                private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(matrixWithAllocationConfig: MatrixWithAllocationConfig) = apply {
                     allocation = matrixWithAllocationConfig.allocation
                     defaultUnitAmount = matrixWithAllocationConfig.defaultUnitAmount
-                    dimensions = matrixWithAllocationConfig.dimensions.toMutableList()
-                    matrixValues = matrixWithAllocationConfig.matrixValues.toMutableList()
+                    dimensions = matrixWithAllocationConfig.dimensions.map { it.toMutableList() }
+                    matrixValues =
+                        matrixWithAllocationConfig.matrixValues.map { it.toMutableList() }
                     additionalProperties =
                         matrixWithAllocationConfig.additionalProperties.toMutableMap()
                 }
 
                 /** Allocation to be used to calculate the price */
-                fun allocation(allocation: Double) = apply { this.allocation = allocation }
+                fun allocation(allocation: Double) = allocation(JsonField.of(allocation))
+
+                /** Allocation to be used to calculate the price */
+                fun allocation(allocation: JsonField<Double>) = apply {
+                    this.allocation = allocation
+                }
+
+                /**
+                 * Default per unit rate for any usage not bucketed into a specified matrix_value
+                 */
+                fun defaultUnitAmount(defaultUnitAmount: String) =
+                    defaultUnitAmount(JsonField.of(defaultUnitAmount))
 
                 /**
                  * Default per unit rate for any usage not bucketed into a specified matrix_value
                  */
-                fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                     this.defaultUnitAmount = defaultUnitAmount
                 }
 
                 /** One or two event property values to evaluate matrix groups by */
-                fun dimensions(dimensions: List<String?>) = apply {
-                    this.dimensions = dimensions.toMutableList()
+                fun dimensions(dimensions: List<String?>) = dimensions(JsonField.of(dimensions))
+
+                /** One or two event property values to evaluate matrix groups by */
+                fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                    this.dimensions = dimensions.map { it.toMutableList() }
                 }
 
                 /** One or two event property values to evaluate matrix groups by */
                 fun addDimension(dimension: String) = apply {
-                    dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                    dimensions =
+                        (dimensions ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(dimension)
+                        }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
-                fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                    this.matrixValues = matrixValues.toMutableList()
+                fun matrixValues(matrixValues: List<MatrixValue>) =
+                    matrixValues(JsonField.of(matrixValues))
+
+                /** Matrix values for specified matrix grouping keys */
+                fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                    this.matrixValues = matrixValues.map { it.toMutableList() }
                 }
 
                 /** Matrix values for specified matrix grouping keys */
                 fun addMatrixValue(matrixValue: MatrixValue) = apply {
-                    matrixValues = (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                    matrixValues =
+                        (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(matrixValue)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -4902,9 +6161,9 @@ constructor(
                             "`defaultUnitAmount` is required but was not set"
                         },
                         checkNotNull(dimensions) { "`dimensions` is required but was not set" }
-                            .toImmutable(),
+                            .map { it.toImmutable() },
                         checkNotNull(matrixValues) { "`matrixValues` is required but was not set" }
-                            .toImmutable(),
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4913,27 +6172,55 @@ constructor(
             class MatrixValue
             @JsonCreator
             private constructor(
-                @JsonProperty("dimension_values") private val dimensionValues: List<String?>,
-                @JsonProperty("unit_amount") private val unitAmount: String,
+                @JsonProperty("dimension_values")
+                @ExcludeMissing
+                private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                private val unitAmount: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                /**
+                 * One or two matrix keys to filter usage to this Matrix value by. For example,
+                 * ["region", "tier"] could be used to filter cloud usage by a cloud region and an
+                 * instance tier.
+                 */
+                fun dimensionValues(): List<String?> =
+                    dimensionValues.getRequired("dimension_values")
+
+                /** Unit price for the specified dimension_values */
+                fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                 /**
                  * One or two matrix keys to filter usage to this Matrix value by. For example,
                  * ["region", "tier"] could be used to filter cloud usage by a cloud region and an
                  * instance tier.
                  */
                 @JsonProperty("dimension_values")
-                fun dimensionValues(): List<String?> = dimensionValues
+                @ExcludeMissing
+                fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                 /** Unit price for the specified dimension_values */
-                @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): MatrixValue = apply {
+                    if (!validated) {
+                        dimensionValues()
+                        unitAmount()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4943,13 +6230,13 @@ constructor(
 
                 class Builder {
 
-                    private var dimensionValues: MutableList<String?>? = null
-                    private var unitAmount: String? = null
+                    private var dimensionValues: JsonField<MutableList<String?>>? = null
+                    private var unitAmount: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(matrixValue: MatrixValue) = apply {
-                        dimensionValues = matrixValue.dimensionValues.toMutableList()
+                        dimensionValues = matrixValue.dimensionValues.map { it.toMutableList() }
                         unitAmount = matrixValue.unitAmount
                         additionalProperties = matrixValue.additionalProperties.toMutableMap()
                     }
@@ -4959,8 +6246,16 @@ constructor(
                      * ["region", "tier"] could be used to filter cloud usage by a cloud region and
                      * an instance tier.
                      */
-                    fun dimensionValues(dimensionValues: List<String?>) = apply {
-                        this.dimensionValues = dimensionValues.toMutableList()
+                    fun dimensionValues(dimensionValues: List<String?>) =
+                        dimensionValues(JsonField.of(dimensionValues))
+
+                    /**
+                     * One or two matrix keys to filter usage to this Matrix value by. For example,
+                     * ["region", "tier"] could be used to filter cloud usage by a cloud region and
+                     * an instance tier.
+                     */
+                    fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                        this.dimensionValues = dimensionValues.map { it.toMutableList() }
                     }
 
                     /**
@@ -4970,11 +6265,24 @@ constructor(
                      */
                     fun addDimensionValue(dimensionValue: String) = apply {
                         dimensionValues =
-                            (dimensionValues ?: mutableListOf()).apply { add(dimensionValue) }
+                            (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(dimensionValue)
+                            }
                     }
 
                     /** Unit price for the specified dimension_values */
-                    fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                    fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                    /** Unit price for the specified dimension_values */
+                    fun unitAmount(unitAmount: JsonField<String>) = apply {
+                        this.unitAmount = unitAmount
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -5003,7 +6311,7 @@ constructor(
                             checkNotNull(dimensionValues) {
                                     "`dimensionValues` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(unitAmount) { "`unitAmount` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
@@ -5101,22 +6409,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -5126,8 +6456,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5139,10 +6469,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -5259,22 +6596,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -5284,8 +6643,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5298,10 +6657,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -5427,6 +6793,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -5482,119 +6856,249 @@ constructor(
 
             override fun hashCode(): Int = hashCode
 
-            override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
-        }
+            override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
+        }
+
+        override fun equals(other: Any?): Boolean {
+            if (this === other) {
+                return true
+            }
+
+            return /* spotless:off */ other is NewFloatingMatrixWithAllocationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && matrixWithAllocationConfig == other.matrixWithAllocationConfig && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+        }
+
+        /* spotless:off */
+        private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, matrixWithAllocationConfig, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+        /* spotless:on */
+
+        override fun hashCode(): Int = hashCode
+
+        override fun toString() =
+            "NewFloatingMatrixWithAllocationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, matrixWithAllocationConfig=$matrixWithAllocationConfig, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+    }
+
+    @NoAutoDetect
+    class NewFloatingTieredPrice
+    @JsonCreator
+    private constructor(
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("tiered_config")
+        @ExcludeMissing
+        private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_cycle_configuration")
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoicing_cycle_configuration")
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonAnySetter
+        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+    ) {
+
+        /** The cadence to bill for this price on. */
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
 
-        override fun equals(other: Any?): Boolean {
-            if (this === other) {
-                return true
-            }
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-            return /* spotless:off */ other is NewFloatingMatrixWithAllocationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && matrixWithAllocationConfig == other.matrixWithAllocationConfig && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-        }
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-        /* spotless:off */
-        private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, matrixWithAllocationConfig, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-        /* spotless:on */
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-        override fun hashCode(): Int = hashCode
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-        override fun toString() =
-            "NewFloatingMatrixWithAllocationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, matrixWithAllocationConfig=$matrixWithAllocationConfig, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-    }
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
 
-    @NoAutoDetect
-    class NewFloatingTieredPrice
-    @JsonCreator
-    private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-        @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-        @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonAnySetter
-        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-    ) {
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+        @JsonProperty("tiered_config")
+        @ExcludeMissing
+        fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -5604,21 +7108,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredConfig: TieredConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredConfig: JsonField<TieredConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5642,29 +7148,44 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun tieredConfig(tieredConfig: TieredConfig) = apply {
+            fun tieredConfig(tieredConfig: TieredConfig) = tieredConfig(JsonField.of(tieredConfig))
+
+            fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                 this.tieredConfig = tieredConfig
             }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -5672,13 +7193,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -5695,13 +7222,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -5710,10 +7243,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -5723,21 +7262,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -5752,22 +7299,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -5777,12 +7335,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -5791,6 +7357,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -5967,18 +7540,32 @@ constructor(
         class TieredConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("tiers") private val tiers: List<Tier>,
+            @JsonProperty("tiers")
+            @ExcludeMissing
+            private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Tiers for rating based on total usage quantities into the specified tier */
-            @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+            fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+            /** Tiers for rating based on total usage quantities into the specified tier */
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredConfig = apply {
+                if (!validated) {
+                    tiers().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -5988,21 +7575,35 @@ constructor(
 
             class Builder {
 
-                private var tiers: MutableList<Tier>? = null
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(tieredConfig: TieredConfig) = apply {
-                    tiers = tieredConfig.tiers.toMutableList()
+                    tiers = tieredConfig.tiers.map { it.toMutableList() }
                     additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                 }
 
                 /** Tiers for rating based on total usage quantities into the specified tier */
-                fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                /** Tiers for rating based on total usage quantities into the specified tier */
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
 
                 /** Tiers for rating based on total usage quantities into the specified tier */
                 fun addTier(tier: Tier) = apply {
-                    tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -6029,7 +7630,8 @@ constructor(
 
                 fun build(): TieredConfig =
                     TieredConfig(
-                        checkNotNull(tiers) { "`tiers` is required but was not set" }.toImmutable(),
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -6038,27 +7640,59 @@ constructor(
             class Tier
             @JsonCreator
             private constructor(
-                @JsonProperty("first_unit") private val firstUnit: Double,
-                @JsonProperty("unit_amount") private val unitAmount: String,
-                @JsonProperty("last_unit") private val lastUnit: Double?,
+                @JsonProperty("first_unit")
+                @ExcludeMissing
+                private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                private val unitAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("last_unit")
+                @ExcludeMissing
+                private val lastUnit: JsonField<Double> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Inclusive tier starting value */
-                @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                fun firstUnit(): Double = firstUnit.getRequired("first_unit")
+
+                /** Amount per unit */
+                fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                /** Exclusive tier ending value. If null, this is treated as the last tier */
+                fun lastUnit(): Optional<Double> =
+                    Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                /** Inclusive tier starting value */
+                @JsonProperty("first_unit")
+                @ExcludeMissing
+                fun _firstUnit(): JsonField<Double> = firstUnit
 
                 /** Amount per unit */
-                @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 /** Exclusive tier ending value. If null, this is treated as the last tier */
                 @JsonProperty("last_unit")
-                fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                @ExcludeMissing
+                fun _lastUnit(): JsonField<Double> = lastUnit
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Tier = apply {
+                    if (!validated) {
+                        firstUnit()
+                        unitAmount()
+                        lastUnit()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6068,9 +7702,9 @@ constructor(
 
                 class Builder {
 
-                    private var firstUnit: Double? = null
-                    private var unitAmount: String? = null
-                    private var lastUnit: Double? = null
+                    private var firstUnit: JsonField<Double>? = null
+                    private var unitAmount: JsonField<String>? = null
+                    private var lastUnit: JsonField<Double> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6082,13 +7716,23 @@ constructor(
                     }
 
                     /** Inclusive tier starting value */
-                    fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                    fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                    /** Inclusive tier starting value */
+                    fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                        this.firstUnit = firstUnit
+                    }
+
+                    /** Amount per unit */
+                    fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
 
                     /** Amount per unit */
-                    fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                    fun unitAmount(unitAmount: JsonField<String>) = apply {
+                        this.unitAmount = unitAmount
+                    }
 
                     /** Exclusive tier ending value. If null, this is treated as the last tier */
-                    fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                    fun lastUnit(lastUnit: Double?) = lastUnit(JsonField.ofNullable(lastUnit))
 
                     /** Exclusive tier ending value. If null, this is treated as the last tier */
                     fun lastUnit(lastUnit: Double) = lastUnit(lastUnit as Double?)
@@ -6098,6 +7742,9 @@ constructor(
                     fun lastUnit(lastUnit: Optional<Double>) =
                         lastUnit(lastUnit.orElse(null) as Double?)
 
+                    /** Exclusive tier ending value. If null, this is treated as the last tier */
+                    fun lastUnit(lastUnit: JsonField<Double>) = apply { this.lastUnit = lastUnit }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -6170,22 +7817,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -6195,8 +7864,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -6208,10 +7877,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -6328,22 +8004,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -6353,8 +8051,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -6367,10 +8065,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -6496,6 +8201,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -6576,94 +8289,224 @@ constructor(
     class NewFloatingTieredBpsPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("tiered_bps_config")
+        @ExcludeMissing
+        private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig.getRequired("tiered_bps_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-        @JsonProperty("tiered_bps_config") fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+        @JsonProperty("tiered_bps_config")
+        @ExcludeMissing
+        fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredBpsPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredBpsConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -6673,21 +8516,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredBpsConfig: TieredBpsConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6711,29 +8556,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                tieredBpsConfig(JsonField.of(tieredBpsConfig))
 
-            fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+            fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                 this.tieredBpsConfig = tieredBpsConfig
             }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -6741,13 +8602,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -6764,13 +8631,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -6779,10 +8652,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -6792,21 +8671,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -6821,22 +8708,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -6846,12 +8744,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -6860,6 +8766,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -7038,7 +8951,9 @@ constructor(
         class TieredBpsConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("tiers") private val tiers: List<Tier>,
+            @JsonProperty("tiers")
+            @ExcludeMissing
+            private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
@@ -7046,12 +8961,26 @@ constructor(
             /**
              * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified tiers
              */
-            @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+            fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+            /**
+             * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified tiers
+             */
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredBpsConfig = apply {
+                if (!validated) {
+                    tiers().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -7061,12 +8990,12 @@ constructor(
 
             class Builder {
 
-                private var tiers: MutableList<Tier>? = null
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                    tiers = tieredBpsConfig.tiers.toMutableList()
+                    tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                     additionalProperties = tieredBpsConfig.additionalProperties.toMutableMap()
                 }
 
@@ -7074,14 +9003,31 @@ constructor(
                  * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
                  * tiers
                  */
-                fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                /**
+                 * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
+                 * tiers
+                 */
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
 
                 /**
                  * Tiers for a Graduated BPS pricing model, where usage is bucketed into specified
                  * tiers
                  */
                 fun addTier(tier: Tier) = apply {
-                    tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -7108,7 +9054,8 @@ constructor(
 
                 fun build(): TieredBpsConfig =
                     TieredBpsConfig(
-                        checkNotNull(tiers) { "`tiers` is required but was not set" }.toImmutable(),
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -7117,32 +9064,70 @@ constructor(
             class Tier
             @JsonCreator
             private constructor(
-                @JsonProperty("bps") private val bps: Double,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                @JsonProperty("bps")
+                @ExcludeMissing
+                private val bps: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("per_unit_maximum")
+                @ExcludeMissing
+                private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Per-event basis point rate */
-                @JsonProperty("bps") fun bps(): Double = bps
+                fun bps(): Double = bps.getRequired("bps")
+
+                /** Inclusive tier starting value */
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /** Exclusive tier ending value */
+                fun maximumAmount(): Optional<String> =
+                    Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                /** Per unit maximum to charge */
+                fun perUnitMaximum(): Optional<String> =
+                    Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                /** Per-event basis point rate */
+                @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                 /** Inclusive tier starting value */
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** Exclusive tier ending value */
                 @JsonProperty("maximum_amount")
-                fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** Per unit maximum to charge */
                 @JsonProperty("per_unit_maximum")
-                fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                @ExcludeMissing
+                fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Tier = apply {
+                    if (!validated) {
+                        bps()
+                        minimumAmount()
+                        maximumAmount()
+                        perUnitMaximum()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7152,10 +9137,10 @@ constructor(
 
                 class Builder {
 
-                    private var bps: Double? = null
-                    private var minimumAmount: String? = null
-                    private var maximumAmount: String? = null
-                    private var perUnitMaximum: String? = null
+                    private var bps: JsonField<Double>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var maximumAmount: JsonField<String> = JsonMissing.of()
+                    private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7168,31 +9153,46 @@ constructor(
                     }
 
                     /** Per-event basis point rate */
-                    fun bps(bps: Double) = apply { this.bps = bps }
+                    fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                    /** Per-event basis point rate */
+                    fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                     /** Inclusive tier starting value */
-                    fun minimumAmount(minimumAmount: String) = apply {
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    /** Inclusive tier starting value */
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                         this.minimumAmount = minimumAmount
                     }
 
                     /** Exclusive tier ending value */
-                    fun maximumAmount(maximumAmount: String?) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String?) =
+                        maximumAmount(JsonField.ofNullable(maximumAmount))
 
                     /** Exclusive tier ending value */
                     fun maximumAmount(maximumAmount: Optional<String>) =
                         maximumAmount(maximumAmount.orElse(null))
 
-                    /** Per unit maximum to charge */
-                    fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                        this.perUnitMaximum = perUnitMaximum
+                    /** Exclusive tier ending value */
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
+                    /** Per unit maximum to charge */
+                    fun perUnitMaximum(perUnitMaximum: String?) =
+                        perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                     /** Per unit maximum to charge */
                     fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                         perUnitMaximum(perUnitMaximum.orElse(null))
 
+                    /** Per unit maximum to charge */
+                    fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                        this.perUnitMaximum = perUnitMaximum
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -7268,22 +9268,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -7293,8 +9315,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7306,10 +9328,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -7426,22 +9455,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -7451,8 +9502,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -7465,10 +9516,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -7594,6 +9652,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -7643,125 +9709,255 @@ constructor(
                 return /* spotless:off */ other is Metadata && additionalProperties == other.additionalProperties /* spotless:on */
             }
 
-            /* spotless:off */
-            private val hashCode: Int by lazy { Objects.hash(additionalProperties) }
-            /* spotless:on */
+            /* spotless:off */
+            private val hashCode: Int by lazy { Objects.hash(additionalProperties) }
+            /* spotless:on */
+
+            override fun hashCode(): Int = hashCode
+
+            override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
+        }
+
+        override fun equals(other: Any?): Boolean {
+            if (this === other) {
+                return true
+            }
+
+            return /* spotless:off */ other is NewFloatingTieredBpsPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredBpsConfig == other.tieredBpsConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+        }
+
+        /* spotless:off */
+        private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredBpsConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+        /* spotless:on */
+
+        override fun hashCode(): Int = hashCode
+
+        override fun toString() =
+            "NewFloatingTieredBpsPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredBpsConfig=$tieredBpsConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+    }
+
+    @NoAutoDetect
+    class NewFloatingBpsPrice
+    @JsonCreator
+    private constructor(
+        @JsonProperty("bps_config")
+        @ExcludeMissing
+        private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_cycle_configuration")
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoicing_cycle_configuration")
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonAnySetter
+        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+    ) {
+
+        fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
+
+        /** The cadence to bill for this price on. */
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
 
-            override fun hashCode(): Int = hashCode
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
 
-            override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
-        }
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
 
-        override fun equals(other: Any?): Boolean {
-            if (this === other) {
-                return true
-            }
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-            return /* spotless:off */ other is NewFloatingTieredBpsPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredBpsConfig == other.tieredBpsConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-        }
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-        /* spotless:off */
-        private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredBpsConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-        /* spotless:on */
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-        override fun hashCode(): Int = hashCode
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-        override fun toString() =
-            "NewFloatingTieredBpsPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredBpsConfig=$tieredBpsConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-    }
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
 
-    @NoAutoDetect
-    class NewFloatingBpsPrice
-    @JsonCreator
-    private constructor(
-        @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-        @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-        @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonAnySetter
-        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-    ) {
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
 
-        @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+        @JsonProperty("bps_config")
+        @ExcludeMissing
+        fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingBpsPrice = apply {
+            if (!validated) {
+                bpsConfig().validate()
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -7771,21 +9967,23 @@ constructor(
 
         class Builder {
 
-            private var bpsConfig: BpsConfig? = null
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var bpsConfig: JsonField<BpsConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -7808,28 +10006,43 @@ constructor(
                 additionalProperties = newFloatingBpsPrice.additionalProperties.toMutableMap()
             }
 
-            fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+            fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+            fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply { this.bpsConfig = bpsConfig }
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -7837,13 +10050,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -7860,13 +10079,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -7875,10 +10100,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -7888,21 +10119,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -7917,22 +10156,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -7942,12 +10192,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -7956,6 +10214,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -8000,23 +10265,45 @@ constructor(
         class BpsConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("bps") private val bps: Double,
-            @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+            @JsonProperty("bps")
+            @ExcludeMissing
+            private val bps: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("per_unit_maximum")
+            @ExcludeMissing
+            private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Basis point take rate per event */
-            @JsonProperty("bps") fun bps(): Double = bps
+            fun bps(): Double = bps.getRequired("bps")
+
+            /** Optional currency amount maximum to cap spend per event */
+            fun perUnitMaximum(): Optional<String> =
+                Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+            /** Basis point take rate per event */
+            @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
             /** Optional currency amount maximum to cap spend per event */
             @JsonProperty("per_unit_maximum")
-            fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+            @ExcludeMissing
+            fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BpsConfig = apply {
+                if (!validated) {
+                    bps()
+                    perUnitMaximum()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8026,8 +10313,8 @@ constructor(
 
             class Builder {
 
-                private var bps: Double? = null
-                private var perUnitMaximum: String? = null
+                private var bps: JsonField<Double>? = null
+                private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -8038,17 +10325,24 @@ constructor(
                 }
 
                 /** Basis point take rate per event */
-                fun bps(bps: Double) = apply { this.bps = bps }
+                fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                /** Basis point take rate per event */
+                fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                 /** Optional currency amount maximum to cap spend per event */
-                fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                    this.perUnitMaximum = perUnitMaximum
-                }
+                fun perUnitMaximum(perUnitMaximum: String?) =
+                    perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                 /** Optional currency amount maximum to cap spend per event */
                 fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                     perUnitMaximum(perUnitMaximum.orElse(null))
 
+                /** Optional currency amount maximum to cap spend per event */
+                fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                    this.perUnitMaximum = perUnitMaximum
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -8234,22 +10528,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8259,8 +10575,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -8272,10 +10588,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -8392,22 +10715,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8417,8 +10762,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -8431,10 +10776,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -8560,6 +10912,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8636,98 +10996,228 @@ constructor(
             "NewFloatingBpsPrice{bpsConfig=$bpsConfig, cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
     }
 
-    @NoAutoDetect
-    class NewFloatingBulkBpsPrice
-    @JsonCreator
-    private constructor(
-        @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-        @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-        @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonAnySetter
-        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-    ) {
+    @NoAutoDetect
+    class NewFloatingBulkBpsPrice
+    @JsonCreator
+    private constructor(
+        @JsonProperty("bulk_bps_config")
+        @ExcludeMissing
+        private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_cycle_configuration")
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoicing_cycle_configuration")
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonAnySetter
+        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+    ) {
+
+        fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+        /** The cadence to bill for this price on. */
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
 
-        @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+        @JsonProperty("bulk_bps_config")
+        @ExcludeMissing
+        fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingBulkBpsPrice = apply {
+            if (!validated) {
+                bulkBpsConfig().validate()
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -8737,21 +11227,23 @@ constructor(
 
         class Builder {
 
-            private var bulkBpsConfig: BulkBpsConfig? = null
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -8774,30 +11266,46 @@ constructor(
                 additionalProperties = newFloatingBulkBpsPrice.additionalProperties.toMutableMap()
             }
 
-            fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+            fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+            fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                 this.bulkBpsConfig = bulkBpsConfig
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -8805,13 +11313,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -8828,13 +11342,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -8843,10 +11363,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -8856,21 +11382,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -8885,22 +11419,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -8910,12 +11455,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -8924,6 +11477,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -8968,7 +11528,9 @@ constructor(
         class BulkBpsConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("tiers") private val tiers: List<Tier>,
+            @JsonProperty("tiers")
+            @ExcludeMissing
+            private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
@@ -8977,12 +11539,27 @@ constructor(
              * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
              * based on total volume
              */
-            @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+            fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+            /**
+             * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
+             * based on total volume
+             */
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BulkBpsConfig = apply {
+                if (!validated) {
+                    tiers().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -8992,12 +11569,12 @@ constructor(
 
             class Builder {
 
-                private var tiers: MutableList<Tier>? = null
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                    tiers = bulkBpsConfig.tiers.toMutableList()
+                    tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                     additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                 }
 
@@ -9005,14 +11582,31 @@ constructor(
                  * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
                  * based on total volume
                  */
-                fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                /**
+                 * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
+                 * based on total volume
+                 */
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
 
                 /**
                  * Tiers for a bulk BPS pricing model where all usage is aggregated to a single tier
                  * based on total volume
                  */
                 fun addTier(tier: Tier) = apply {
-                    tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -9039,7 +11633,8 @@ constructor(
 
                 fun build(): BulkBpsConfig =
                     BulkBpsConfig(
-                        checkNotNull(tiers) { "`tiers` is required but was not set" }.toImmutable(),
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -9048,28 +11643,58 @@ constructor(
             class Tier
             @JsonCreator
             private constructor(
-                @JsonProperty("bps") private val bps: Double,
-                @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                @JsonProperty("bps")
+                @ExcludeMissing
+                private val bps: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("per_unit_maximum")
+                @ExcludeMissing
+                private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Basis points to rate on */
-                @JsonProperty("bps") fun bps(): Double = bps
+                fun bps(): Double = bps.getRequired("bps")
+
+                /** Upper bound for tier */
+                fun maximumAmount(): Optional<String> =
+                    Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                /** The maximum amount to charge for any one event */
+                fun perUnitMaximum(): Optional<String> =
+                    Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                /** Basis points to rate on */
+                @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                 /** Upper bound for tier */
                 @JsonProperty("maximum_amount")
-                fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The maximum amount to charge for any one event */
                 @JsonProperty("per_unit_maximum")
-                fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                @ExcludeMissing
+                fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Tier = apply {
+                    if (!validated) {
+                        bps()
+                        maximumAmount()
+                        perUnitMaximum()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9079,9 +11704,9 @@ constructor(
 
                 class Builder {
 
-                    private var bps: Double? = null
-                    private var maximumAmount: String? = null
-                    private var perUnitMaximum: String? = null
+                    private var bps: JsonField<Double>? = null
+                    private var maximumAmount: JsonField<String> = JsonMissing.of()
+                    private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9093,26 +11718,37 @@ constructor(
                     }
 
                     /** Basis points to rate on */
-                    fun bps(bps: Double) = apply { this.bps = bps }
+                    fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                    /** Basis points to rate on */
+                    fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                     /** Upper bound for tier */
-                    fun maximumAmount(maximumAmount: String?) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String?) =
+                        maximumAmount(JsonField.ofNullable(maximumAmount))
 
                     /** Upper bound for tier */
                     fun maximumAmount(maximumAmount: Optional<String>) =
                         maximumAmount(maximumAmount.orElse(null))
 
-                    /** The maximum amount to charge for any one event */
-                    fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                        this.perUnitMaximum = perUnitMaximum
+                    /** Upper bound for tier */
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
+                    /** The maximum amount to charge for any one event */
+                    fun perUnitMaximum(perUnitMaximum: String?) =
+                        perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                     /** The maximum amount to charge for any one event */
                     fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                         perUnitMaximum(perUnitMaximum.orElse(null))
 
+                    /** The maximum amount to charge for any one event */
+                    fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                        this.perUnitMaximum = perUnitMaximum
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -9317,22 +11953,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -9342,8 +12000,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9355,10 +12013,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -9475,22 +12140,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -9500,8 +12187,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -9514,10 +12201,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -9643,6 +12337,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -9706,111 +12408,241 @@ constructor(
                 return true
             }
 
-            return /* spotless:off */ other is NewFloatingBulkBpsPrice && bulkBpsConfig == other.bulkBpsConfig && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-        }
+            return /* spotless:off */ other is NewFloatingBulkBpsPrice && bulkBpsConfig == other.bulkBpsConfig && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+        }
+
+        /* spotless:off */
+        private val hashCode: Int by lazy { Objects.hash(bulkBpsConfig, cadence, currency, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+        /* spotless:on */
+
+        override fun hashCode(): Int = hashCode
+
+        override fun toString() =
+            "NewFloatingBulkBpsPrice{bulkBpsConfig=$bulkBpsConfig, cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+    }
+
+    @NoAutoDetect
+    class NewFloatingBulkPrice
+    @JsonCreator
+    private constructor(
+        @JsonProperty("bulk_config")
+        @ExcludeMissing
+        private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("billing_cycle_configuration")
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoicing_cycle_configuration")
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonAnySetter
+        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+    ) {
+
+        fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
+
+        /** The cadence to bill for this price on. */
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-        /* spotless:off */
-        private val hashCode: Int by lazy { Objects.hash(bulkBpsConfig, cadence, currency, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-        /* spotless:on */
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-        override fun hashCode(): Int = hashCode
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-        override fun toString() =
-            "NewFloatingBulkBpsPrice{bulkBpsConfig=$bulkBpsConfig, cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-    }
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-    @NoAutoDetect
-    class NewFloatingBulkPrice
-    @JsonCreator
-    private constructor(
-        @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-        @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-        @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonAnySetter
-        private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-    ) {
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
 
-        @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+        @JsonProperty("bulk_config")
+        @ExcludeMissing
+        fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingBulkPrice = apply {
+            if (!validated) {
+                bulkConfig().validate()
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -9820,21 +12652,23 @@ constructor(
 
         class Builder {
 
-            private var bulkConfig: BulkConfig? = null
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var bulkConfig: JsonField<BulkConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -9857,28 +12691,45 @@ constructor(
                 additionalProperties = newFloatingBulkPrice.additionalProperties.toMutableMap()
             }
 
-            fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+            fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+            fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                this.bulkConfig = bulkConfig
+            }
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -9886,13 +12737,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -9909,13 +12766,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -9924,10 +12787,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -9937,21 +12806,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -9966,22 +12843,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -9991,12 +12879,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -10005,6 +12901,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -10049,18 +12952,32 @@ constructor(
         class BulkConfig
         @JsonCreator
         private constructor(
-            @JsonProperty("tiers") private val tiers: List<Tier>,
+            @JsonProperty("tiers")
+            @ExcludeMissing
+            private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** Bulk tiers for rating based on total usage volume */
-            @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+            fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+            /** Bulk tiers for rating based on total usage volume */
+            @JsonProperty("tiers") @ExcludeMissing fun _tiers(): JsonField<List<Tier>> = tiers
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BulkConfig = apply {
+                if (!validated) {
+                    tiers().forEach { it.validate() }
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -10070,21 +12987,35 @@ constructor(
 
             class Builder {
 
-                private var tiers: MutableList<Tier>? = null
+                private var tiers: JsonField<MutableList<Tier>>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(bulkConfig: BulkConfig) = apply {
-                    tiers = bulkConfig.tiers.toMutableList()
+                    tiers = bulkConfig.tiers.map { it.toMutableList() }
                     additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                 }
 
                 /** Bulk tiers for rating based on total usage volume */
-                fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                /** Bulk tiers for rating based on total usage volume */
+                fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                    this.tiers = tiers.map { it.toMutableList() }
+                }
 
                 /** Bulk tiers for rating based on total usage volume */
                 fun addTier(tier: Tier) = apply {
-                    tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                    tiers =
+                        (tiers ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(tier)
+                        }
                 }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -10111,7 +13042,8 @@ constructor(
 
                 fun build(): BulkConfig =
                     BulkConfig(
-                        checkNotNull(tiers) { "`tiers` is required but was not set" }.toImmutable(),
+                        checkNotNull(tiers) { "`tiers` is required but was not set" }
+                            .map { it.toImmutable() },
                         additionalProperties.toImmutable()
                     )
             }
@@ -10120,23 +13052,47 @@ constructor(
             class Tier
             @JsonCreator
             private constructor(
-                @JsonProperty("unit_amount") private val unitAmount: String,
-                @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                private val unitAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("maximum_units")
+                @ExcludeMissing
+                private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Amount per unit */
-                @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                /** Upper bound for this tier */
+                fun maximumUnits(): Optional<Double> =
+                    Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                /** Amount per unit */
+                @JsonProperty("unit_amount")
+                @ExcludeMissing
+                fun _unitAmount(): JsonField<String> = unitAmount
 
                 /** Upper bound for this tier */
                 @JsonProperty("maximum_units")
-                fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                @ExcludeMissing
+                fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): Tier = apply {
+                    if (!validated) {
+                        unitAmount()
+                        maximumUnits()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10146,8 +13102,8 @@ constructor(
 
                 class Builder {
 
-                    private var unitAmount: String? = null
-                    private var maximumUnits: Double? = null
+                    private var unitAmount: JsonField<String>? = null
+                    private var maximumUnits: JsonField<Double> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10158,13 +13114,17 @@ constructor(
                     }
 
                     /** Amount per unit */
-                    fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                    fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
 
-                    /** Upper bound for this tier */
-                    fun maximumUnits(maximumUnits: Double?) = apply {
-                        this.maximumUnits = maximumUnits
+                    /** Amount per unit */
+                    fun unitAmount(unitAmount: JsonField<String>) = apply {
+                        this.unitAmount = unitAmount
                     }
 
+                    /** Upper bound for this tier */
+                    fun maximumUnits(maximumUnits: Double?) =
+                        maximumUnits(JsonField.ofNullable(maximumUnits))
+
                     /** Upper bound for this tier */
                     fun maximumUnits(maximumUnits: Double) = maximumUnits(maximumUnits as Double?)
 
@@ -10173,6 +13133,11 @@ constructor(
                     fun maximumUnits(maximumUnits: Optional<Double>) =
                         maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                    /** Upper bound for this tier */
+                    fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                        this.maximumUnits = maximumUnits
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -10376,22 +13341,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -10401,8 +13388,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -10414,10 +13401,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -10534,22 +13528,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -10559,8 +13575,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -10573,10 +13589,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -10702,6 +13725,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -10782,96 +13813,227 @@ constructor(
     class NewFloatingThresholdTotalAmountPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("threshold_total_amount_config")
-        private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+            JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+            thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("threshold_total_amount_config")
-        fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig = thresholdTotalAmountConfig
+        @ExcludeMissing
+        fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
+            thresholdTotalAmountConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingThresholdTotalAmountPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                thresholdTotalAmountConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -10881,21 +14043,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -10925,30 +14089,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun thresholdTotalAmountConfig(thresholdTotalAmountConfig: ThresholdTotalAmountConfig) =
-                apply {
-                    this.thresholdTotalAmountConfig = thresholdTotalAmountConfig
-                }
+                thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+            fun thresholdTotalAmountConfig(
+                thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
+            ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -10956,13 +14135,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -10979,13 +14164,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -10994,10 +14185,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -11007,21 +14204,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -11036,22 +14241,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -11061,12 +14277,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -11075,6 +14299,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -11261,6 +14492,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): ThresholdTotalAmountConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -11327,22 +14566,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -11352,8 +14613,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11365,10 +14626,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -11485,22 +14753,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -11510,8 +14800,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -11524,10 +14814,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -11653,6 +14950,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -11733,95 +15038,225 @@ constructor(
     class NewFloatingTieredPackagePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("tiered_package_config") private val tieredPackageConfig: TieredPackageConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("tiered_package_config")
+        @ExcludeMissing
+        private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun tieredPackageConfig(): TieredPackageConfig =
+            tieredPackageConfig.getRequired("tiered_package_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("tiered_package_config")
-        fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+        @ExcludeMissing
+        fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredPackagePrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredPackageConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -11831,21 +15266,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredPackageConfig: TieredPackageConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -11873,29 +15310,45 @@ constructor(
                 }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
-            fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
+            fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+            fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) = apply {
                 this.tieredPackageConfig = tieredPackageConfig
             }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -11903,13 +15356,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -11926,13 +15385,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -11941,10 +15406,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -11954,21 +15425,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
-             */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -11983,22 +15462,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -12008,12 +15498,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -12022,6 +15520,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -12208,6 +15713,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredPackageConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -12273,22 +15786,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -12298,8 +15833,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -12311,10 +15846,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -12431,22 +15973,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -12456,8 +16020,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -12470,10 +16034,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -12599,6 +16170,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -12679,95 +16258,225 @@ constructor(
     class NewFloatingGroupedTieredPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("grouped_tiered_config") private val groupedTieredConfig: GroupedTieredConfig,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("grouped_tiered_config")
+        @ExcludeMissing
+        private val groupedTieredConfig: JsonField<GroupedTieredConfig> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        fun groupedTieredConfig(): GroupedTieredConfig =
+            groupedTieredConfig.getRequired("grouped_tiered_config")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         @JsonProperty("grouped_tiered_config")
-        fun groupedTieredConfig(): GroupedTieredConfig = groupedTieredConfig
+        @ExcludeMissing
+        fun _groupedTieredConfig(): JsonField<GroupedTieredConfig> = groupedTieredConfig
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingGroupedTieredPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                groupedTieredConfig().validate()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -12777,21 +16486,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var groupedTieredConfig: GroupedTieredConfig? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var groupedTieredConfig: JsonField<GroupedTieredConfig>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -12819,29 +16530,45 @@ constructor(
                 }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
-            fun groupedTieredConfig(groupedTieredConfig: GroupedTieredConfig) = apply {
+            fun groupedTieredConfig(groupedTieredConfig: GroupedTieredConfig) =
+                groupedTieredConfig(JsonField.of(groupedTieredConfig))
+
+            fun groupedTieredConfig(groupedTieredConfig: JsonField<GroupedTieredConfig>) = apply {
                 this.groupedTieredConfig = groupedTieredConfig
             }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -12849,13 +16576,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -12872,13 +16605,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -12887,10 +16626,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -12900,21 +16645,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -12929,22 +16682,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -12954,12 +16718,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -12968,6 +16740,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -13103,6 +16882,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): GroupedTieredConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -13219,22 +17006,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -13244,8 +17053,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13257,10 +17066,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -13377,22 +17193,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -13402,8 +17240,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -13416,10 +17254,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -13545,6 +17390,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -13625,96 +17478,225 @@ constructor(
     class NewFloatingTieredWithMinimumPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("tiered_with_minimum_config")
-        private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+            tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("tiered_with_minimum_config")
-        fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+        @ExcludeMissing
+        fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> = tieredWithMinimumConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredWithMinimumPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredWithMinimumConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -13724,21 +17706,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -13767,29 +17751,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
 
-            fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) = apply {
-                this.tieredWithMinimumConfig = tieredWithMinimumConfig
-            }
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
+                tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+            fun tieredWithMinimumConfig(
+                tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+            ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -13797,13 +17797,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -13820,13 +17826,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -13835,10 +17847,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -13848,21 +17866,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -13877,22 +17903,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -13902,12 +17939,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -13916,6 +17961,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -14102,6 +18154,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredWithMinimumConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -14168,22 +18228,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -14193,8 +18275,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -14206,10 +18288,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -14326,22 +18415,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -14351,8 +18462,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -14365,10 +18476,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -14494,6 +18612,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -14574,96 +18700,227 @@ constructor(
     class NewFloatingPackageWithAllocationPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("package_with_allocation_config")
-        private val packageWithAllocationConfig: PackageWithAllocationConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+            JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+            packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("package_with_allocation_config")
-        fun packageWithAllocationConfig(): PackageWithAllocationConfig = packageWithAllocationConfig
+        @ExcludeMissing
+        fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
+            packageWithAllocationConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingPackageWithAllocationPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                packageWithAllocationConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -14673,21 +18930,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -14717,29 +18976,46 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun packageWithAllocationConfig(
                 packageWithAllocationConfig: PackageWithAllocationConfig
+            ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+            fun packageWithAllocationConfig(
+                packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
             ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -14747,13 +19023,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -14770,13 +19052,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -14785,10 +19073,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -14798,21 +19092,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -14827,22 +19129,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -14852,12 +19165,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -14866,6 +19187,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -15052,6 +19380,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): PackageWithAllocationConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -15119,22 +19455,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -15144,8 +19502,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15157,10 +19515,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -15277,22 +19642,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -15302,8 +19689,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -15316,10 +19703,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -15445,6 +19839,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -15525,97 +19927,227 @@ constructor(
     class NewFloatingTieredPackageWithMinimumPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("tiered_package_with_minimum_config")
-        private val tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig> =
+            JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        fun itemId(): String = itemId.getRequired("item_id")
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        fun modelType(): ModelType = modelType.getRequired("model_type")
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        fun name(): String = name.getRequired("name")
 
-        @JsonProperty("tiered_package_with_minimum_config")
         fun tieredPackageWithMinimumConfig(): TieredPackageWithMinimumConfig =
+            tieredPackageWithMinimumConfig.getRequired("tiered_package_with_minimum_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+        /** The id of the item the plan will be associated with. */
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
+
+        /** The name of the price. */
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+        @JsonProperty("tiered_package_with_minimum_config")
+        @ExcludeMissing
+        fun _tieredPackageWithMinimumConfig(): JsonField<TieredPackageWithMinimumConfig> =
             tieredPackageWithMinimumConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredPackageWithMinimumPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredPackageWithMinimumConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -15625,21 +20157,24 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig>? =
+                null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -15669,29 +20204,46 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun tieredPackageWithMinimumConfig(
                 tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig
+            ) = tieredPackageWithMinimumConfig(JsonField.of(tieredPackageWithMinimumConfig))
+
+            fun tieredPackageWithMinimumConfig(
+                tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig>
             ) = apply { this.tieredPackageWithMinimumConfig = tieredPackageWithMinimumConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -15699,13 +20251,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -15722,13 +20280,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -15737,10 +20301,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -15750,21 +20320,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
-             */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -15779,22 +20357,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -15804,12 +20393,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -15818,6 +20415,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -16004,6 +20608,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredPackageWithMinimumConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -16071,22 +20683,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -16096,8 +20730,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -16109,10 +20743,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -16229,22 +20870,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -16254,8 +20917,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -16268,10 +20931,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -16397,6 +21067,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -16477,96 +21155,225 @@ constructor(
     class NewFloatingUnitWithPercentPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("unit_with_percent_config")
-        private val unitWithPercentConfig: UnitWithPercentConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun unitWithPercentConfig(): UnitWithPercentConfig =
+            unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("unit_with_percent_config")
-        fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+        @ExcludeMissing
+        fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> = unitWithPercentConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingUnitWithPercentPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                unitWithPercentConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -16576,21 +21383,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var unitWithPercentConfig: UnitWithPercentConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -16618,29 +21427,46 @@ constructor(
                 }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
 
-            fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) = apply {
-                this.unitWithPercentConfig = unitWithPercentConfig
-            }
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
+                unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+            fun unitWithPercentConfig(unitWithPercentConfig: JsonField<UnitWithPercentConfig>) =
+                apply {
+                    this.unitWithPercentConfig = unitWithPercentConfig
+                }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -16648,13 +21474,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -16671,13 +21503,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -16686,10 +21524,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -16699,21 +21543,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -16728,22 +21580,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -16753,12 +21616,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -16767,6 +21638,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -16953,6 +21831,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): UnitWithPercentConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17018,22 +21904,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17043,8 +21951,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17056,10 +21964,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -17176,22 +22091,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17201,8 +22138,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -17215,10 +22152,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -17344,6 +22288,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17424,96 +22376,227 @@ constructor(
     class NewFloatingTieredWithProrationPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("tiered_with_proration_config")
-        private val tieredWithProrationConfig: TieredWithProrationConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+            JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun tieredWithProrationConfig(): TieredWithProrationConfig =
+            tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("tiered_with_proration_config")
-        fun tieredWithProrationConfig(): TieredWithProrationConfig = tieredWithProrationConfig
+        @ExcludeMissing
+        fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
+            tieredWithProrationConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingTieredWithProrationPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                tieredWithProrationConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -17523,21 +22606,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -17567,30 +22652,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             fun tieredWithProrationConfig(tieredWithProrationConfig: TieredWithProrationConfig) =
-                apply {
-                    this.tieredWithProrationConfig = tieredWithProrationConfig
-                }
+                tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+            fun tieredWithProrationConfig(
+                tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
+            ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -17598,13 +22698,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -17621,13 +22727,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -17636,10 +22748,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -17649,21 +22767,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -17678,22 +22804,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -17703,12 +22840,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -17717,6 +22862,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -17903,6 +23055,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): TieredWithProrationConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17969,22 +23129,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -17994,8 +23176,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18007,10 +23189,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -18127,22 +23316,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -18152,8 +23363,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18166,10 +23377,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -18295,6 +23513,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -18375,96 +23601,225 @@ constructor(
     class NewFloatingUnitWithProrationPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
         @JsonProperty("unit_with_proration_config")
-        private val unitWithProrationConfig: UnitWithProrationConfig,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        fun unitWithProrationConfig(): UnitWithProrationConfig =
+            unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonProperty("unit_with_proration_config")
-        fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+        @ExcludeMissing
+        fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> = unitWithProrationConfig
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingUnitWithProrationPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                unitWithProrationConfig().validate()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -18474,21 +23829,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var unitWithProrationConfig: UnitWithProrationConfig? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -18517,29 +23874,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
 
-            fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) = apply {
-                this.unitWithProrationConfig = unitWithProrationConfig
-            }
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
+
+            fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
+                unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+            fun unitWithProrationConfig(
+                unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+            ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -18547,13 +23920,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -18570,13 +23949,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -18585,10 +23970,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -18598,21 +23989,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -18627,22 +24026,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -18652,12 +24062,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -18666,6 +24084,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -18852,6 +24277,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): UnitWithProrationConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -18918,22 +24351,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -18943,8 +24398,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -18956,10 +24411,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -19076,22 +24538,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -19101,8 +24585,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19115,10 +24599,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -19244,6 +24735,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -19324,96 +24823,225 @@ constructor(
     class NewFloatingGroupedAllocationPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
         @JsonProperty("grouped_allocation_config")
-        private val groupedAllocationConfig: GroupedAllocationConfig,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        fun groupedAllocationConfig(): GroupedAllocationConfig =
+            groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         @JsonProperty("grouped_allocation_config")
-        fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+        @ExcludeMissing
+        fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> = groupedAllocationConfig
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingGroupedAllocationPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                groupedAllocationConfig().validate()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -19423,21 +25051,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var groupedAllocationConfig: GroupedAllocationConfig? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -19466,29 +25096,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
-            fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) = apply {
-                this.groupedAllocationConfig = groupedAllocationConfig
-            }
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
+                groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+            fun groupedAllocationConfig(
+                groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+            ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -19496,13 +25142,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -19519,13 +25171,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -19534,10 +25192,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -19547,21 +25211,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -19576,22 +25248,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -19601,12 +25284,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -19615,6 +25306,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -19750,6 +25448,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): GroupedAllocationConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -19867,22 +25573,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -19892,8 +25620,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -19905,10 +25633,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -20025,22 +25760,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -20050,8 +25807,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20064,10 +25821,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -20193,6 +25957,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -20273,97 +26045,227 @@ constructor(
     class NewFloatingGroupedWithProratedMinimumPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
         @JsonProperty("grouped_with_prorated_minimum_config")
-        private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val groupedWithProratedMinimumConfig: JsonField<GroupedWithProratedMinimumConfig> =
+            JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
 
-        @JsonProperty("grouped_with_prorated_minimum_config")
         fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
+            groupedWithProratedMinimumConfig.getRequired("grouped_with_prorated_minimum_config")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+        @JsonProperty("grouped_with_prorated_minimum_config")
+        @ExcludeMissing
+        fun _groupedWithProratedMinimumConfig(): JsonField<GroupedWithProratedMinimumConfig> =
             groupedWithProratedMinimumConfig
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingGroupedWithProratedMinimumPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                groupedWithProratedMinimumConfig().validate()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -20373,21 +26275,25 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var groupedWithProratedMinimumConfig:
+                JsonField<GroupedWithProratedMinimumConfig>? =
+                null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -20418,29 +26324,46 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             fun groupedWithProratedMinimumConfig(
                 groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+            ) = groupedWithProratedMinimumConfig(JsonField.of(groupedWithProratedMinimumConfig))
+
+            fun groupedWithProratedMinimumConfig(
+                groupedWithProratedMinimumConfig: JsonField<GroupedWithProratedMinimumConfig>
             ) = apply { this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -20448,13 +26371,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -20471,13 +26400,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -20486,10 +26421,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -20499,21 +26440,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -20528,22 +26477,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -20553,12 +26513,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -20567,6 +26535,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -20702,6 +26677,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): GroupedWithProratedMinimumConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -20821,22 +26804,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -20846,8 +26851,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -20859,10 +26864,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -20979,22 +26991,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21004,8 +27038,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21018,10 +27052,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -21147,6 +27188,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21227,97 +27276,227 @@ constructor(
     class NewFloatingGroupedWithMeteredMinimumPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
         @JsonProperty("grouped_with_metered_minimum_config")
-        private val groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val groupedWithMeteredMinimumConfig: JsonField<GroupedWithMeteredMinimumConfig> =
+            JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        fun currency(): String = currency.getRequired("currency")
 
-        @JsonProperty("grouped_with_metered_minimum_config")
         fun groupedWithMeteredMinimumConfig(): GroupedWithMeteredMinimumConfig =
+            groupedWithMeteredMinimumConfig.getRequired("grouped_with_metered_minimum_config")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
+
+        @JsonProperty("grouped_with_metered_minimum_config")
+        @ExcludeMissing
+        fun _groupedWithMeteredMinimumConfig(): JsonField<GroupedWithMeteredMinimumConfig> =
             groupedWithMeteredMinimumConfig
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingGroupedWithMeteredMinimumPrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                groupedWithMeteredMinimumConfig().validate()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -21327,21 +27506,25 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var groupedWithMeteredMinimumConfig:
+                JsonField<GroupedWithMeteredMinimumConfig>? =
+                null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -21371,29 +27554,46 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             fun groupedWithMeteredMinimumConfig(
                 groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig
+            ) = groupedWithMeteredMinimumConfig(JsonField.of(groupedWithMeteredMinimumConfig))
+
+            fun groupedWithMeteredMinimumConfig(
+                groupedWithMeteredMinimumConfig: JsonField<GroupedWithMeteredMinimumConfig>
             ) = apply { this.groupedWithMeteredMinimumConfig = groupedWithMeteredMinimumConfig }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -21401,13 +27601,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -21424,13 +27630,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -21439,10 +27651,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -21452,21 +27670,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -21481,22 +27707,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -21506,12 +27743,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -21520,6 +27765,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -21655,6 +27907,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): GroupedWithMeteredMinimumConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21774,22 +28034,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21799,8 +28081,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21812,10 +28094,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -21932,22 +28221,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -21957,8 +28268,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -21971,10 +28282,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -22100,6 +28418,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -22180,96 +28506,227 @@ constructor(
     class NewFloatingMatrixWithDisplayNamePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
         @JsonProperty("matrix_with_display_name_config")
-        private val matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig> =
+            JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun matrixWithDisplayNameConfig(): MatrixWithDisplayNameConfig =
+            matrixWithDisplayNameConfig.getRequired("matrix_with_display_name_config")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
         @JsonProperty("matrix_with_display_name_config")
-        fun matrixWithDisplayNameConfig(): MatrixWithDisplayNameConfig = matrixWithDisplayNameConfig
+        @ExcludeMissing
+        fun _matrixWithDisplayNameConfig(): JsonField<MatrixWithDisplayNameConfig> =
+            matrixWithDisplayNameConfig
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingMatrixWithDisplayNamePrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                itemId()
+                matrixWithDisplayNameConfig().validate()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -22279,21 +28736,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -22323,29 +28782,46 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
             fun matrixWithDisplayNameConfig(
                 matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig
+            ) = matrixWithDisplayNameConfig(JsonField.of(matrixWithDisplayNameConfig))
+
+            fun matrixWithDisplayNameConfig(
+                matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>
             ) = apply { this.matrixWithDisplayNameConfig = matrixWithDisplayNameConfig }
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
+
+            /** The name of the price. */
+            fun name(name: String) = name(JsonField.of(name))
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -22353,13 +28829,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -22376,13 +28858,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -22391,10 +28879,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -22404,21 +28898,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -22433,22 +28935,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -22458,12 +28971,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -22472,6 +28993,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -22607,6 +29135,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): MatrixWithDisplayNameConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -22725,22 +29261,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -22750,8 +29308,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22763,10 +29321,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -22883,22 +29448,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -22908,8 +29495,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -22922,10 +29509,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -23051,6 +29645,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -23132,95 +29734,224 @@ constructor(
     @JsonCreator
     private constructor(
         @JsonProperty("bulk_with_proration_config")
-        private val bulkWithProrationConfig: BulkWithProrationConfig,
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> = JsonMissing.of(),
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        fun bulkWithProrationConfig(): BulkWithProrationConfig =
+            bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+        /** The cadence to bill for this price on. */
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
         @JsonProperty("bulk_with_proration_config")
-        fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+        @ExcludeMissing
+        fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> = bulkWithProrationConfig
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingBulkWithProrationPrice = apply {
+            if (!validated) {
+                bulkWithProrationConfig().validate()
+                cadence()
+                currency()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -23230,21 +29961,23 @@ constructor(
 
         class Builder {
 
-            private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -23272,30 +30005,46 @@ constructor(
                     newFloatingBulkWithProrationPrice.additionalProperties.toMutableMap()
             }
 
-            fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) = apply {
-                this.bulkWithProrationConfig = bulkWithProrationConfig
-            }
+            fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
+                bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+            fun bulkWithProrationConfig(
+                bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+            ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: String) = currency(JsonField.of(currency))
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -23303,13 +30052,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -23326,13 +30081,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -23341,10 +30102,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -23354,21 +30121,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -23383,22 +30158,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -23408,12 +30194,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -23422,6 +30216,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -23476,6 +30277,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BulkWithProrationConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -23674,22 +30483,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -23699,8 +30530,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -23712,10 +30543,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -23832,22 +30670,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -23857,8 +30717,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -23871,10 +30731,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -24000,6 +30867,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -24080,96 +30955,227 @@ constructor(
     class NewFloatingGroupedTieredPackagePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("cadence") private val cadence: Cadence,
-        @JsonProperty("currency") private val currency: String,
+        @JsonProperty("cadence")
+        @ExcludeMissing
+        private val cadence: JsonField<Cadence> = JsonMissing.of(),
+        @JsonProperty("currency")
+        @ExcludeMissing
+        private val currency: JsonField<String> = JsonMissing.of(),
         @JsonProperty("grouped_tiered_package_config")
-        private val groupedTieredPackageConfig: GroupedTieredPackageConfig,
-        @JsonProperty("item_id") private val itemId: String,
-        @JsonProperty("model_type") private val modelType: ModelType,
-        @JsonProperty("name") private val name: String,
-        @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-        @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+        @ExcludeMissing
+        private val groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig> =
+            JsonMissing.of(),
+        @JsonProperty("item_id")
+        @ExcludeMissing
+        private val itemId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        private val modelType: JsonField<ModelType> = JsonMissing.of(),
+        @JsonProperty("name")
+        @ExcludeMissing
+        private val name: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billable_metric_id")
+        @ExcludeMissing
+        private val billableMetricId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billed_in_advance")
+        @ExcludeMissing
+        private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_configuration")
-        private val billingCycleConfiguration: BillingCycleConfiguration?,
-        @JsonProperty("conversion_rate") private val conversionRate: Double?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+        @ExcludeMissing
+        private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("conversion_rate")
+        @ExcludeMissing
+        private val conversionRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("invoice_grouping_key")
+        @ExcludeMissing
+        private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
         @JsonProperty("invoicing_cycle_configuration")
-        private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @ExcludeMissing
+        private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The cadence to bill for this price on. */
-        @JsonProperty("cadence") fun cadence(): Cadence = cadence
+        fun cadence(): Cadence = cadence.getRequired("cadence")
+
+        /** An ISO 4217 currency string for which this price is billed in. */
+        fun currency(): String = currency.getRequired("currency")
+
+        fun groupedTieredPackageConfig(): GroupedTieredPackageConfig =
+            groupedTieredPackageConfig.getRequired("grouped_tiered_package_config")
+
+        /** The id of the item the plan will be associated with. */
+        fun itemId(): String = itemId.getRequired("item_id")
+
+        fun modelType(): ModelType = modelType.getRequired("model_type")
+
+        /** The name of the price. */
+        fun name(): String = name.getRequired("name")
+
+        /** The id of the billable metric for the price. Only needed if the price is usage-based. */
+        fun billableMetricId(): Optional<String> =
+            Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+        /**
+         * If the Price represents a fixed cost, the price will be billed in-advance if this is
+         * true, and in-arrears if this is false.
+         */
+        fun billedInAdvance(): Optional<Boolean> =
+            Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+        /** For custom cadence: specifies the duration of the billing period in days or months. */
+        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+            Optional.ofNullable(
+                billingCycleConfiguration.getNullable("billing_cycle_configuration")
+            )
+
+        /** The per unit conversion rate of the price currency to the invoicing currency. */
+        fun conversionRate(): Optional<Double> =
+            Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+        /** An alias for the price. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** If the Price represents a fixed cost, this represents the quantity of units applied. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /** The property used to group this price on an invoice */
+        fun invoiceGroupingKey(): Optional<String> =
+            Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+        /**
+         * Within each billing cycle, specifies the cadence at which invoices are produced. If
+         * unspecified, a single invoice is produced per billing cycle.
+         */
+        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+            Optional.ofNullable(
+                invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+            )
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /** The cadence to bill for this price on. */
+        @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
         /** An ISO 4217 currency string for which this price is billed in. */
-        @JsonProperty("currency") fun currency(): String = currency
+        @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
         @JsonProperty("grouped_tiered_package_config")
-        fun groupedTieredPackageConfig(): GroupedTieredPackageConfig = groupedTieredPackageConfig
+        @ExcludeMissing
+        fun _groupedTieredPackageConfig(): JsonField<GroupedTieredPackageConfig> =
+            groupedTieredPackageConfig
 
         /** The id of the item the plan will be associated with. */
-        @JsonProperty("item_id") fun itemId(): String = itemId
+        @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-        @JsonProperty("model_type") fun modelType(): ModelType = modelType
+        @JsonProperty("model_type")
+        @ExcludeMissing
+        fun _modelType(): JsonField<ModelType> = modelType
 
         /** The name of the price. */
-        @JsonProperty("name") fun name(): String = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         /** The id of the billable metric for the price. Only needed if the price is usage-based. */
         @JsonProperty("billable_metric_id")
-        fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+        @ExcludeMissing
+        fun _billableMetricId(): JsonField<String> = billableMetricId
 
         /**
          * If the Price represents a fixed cost, the price will be billed in-advance if this is
          * true, and in-arrears if this is false.
          */
         @JsonProperty("billed_in_advance")
-        fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+        @ExcludeMissing
+        fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
         /** For custom cadence: specifies the duration of the billing period in days or months. */
         @JsonProperty("billing_cycle_configuration")
-        fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-            Optional.ofNullable(billingCycleConfiguration)
+        @ExcludeMissing
+        fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+            billingCycleConfiguration
 
         /** The per unit conversion rate of the price currency to the invoicing currency. */
         @JsonProperty("conversion_rate")
-        fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+        @ExcludeMissing
+        fun _conversionRate(): JsonField<Double> = conversionRate
 
         /** An alias for the price. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** If the Price represents a fixed cost, this represents the quantity of units applied. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /** The property used to group this price on an invoice */
         @JsonProperty("invoice_grouping_key")
-        fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+        @ExcludeMissing
+        fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
         /**
          * Within each billing cycle, specifies the cadence at which invoices are produced. If
          * unspecified, a single invoice is produced per billing cycle.
          */
         @JsonProperty("invoicing_cycle_configuration")
-        fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-            Optional.ofNullable(invoicingCycleConfiguration)
+        @ExcludeMissing
+        fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+            invoicingCycleConfiguration
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): NewFloatingGroupedTieredPackagePrice = apply {
+            if (!validated) {
+                cadence()
+                currency()
+                groupedTieredPackageConfig().validate()
+                itemId()
+                modelType()
+                name()
+                billableMetricId()
+                billedInAdvance()
+                billingCycleConfiguration().map { it.validate() }
+                conversionRate()
+                externalPriceId()
+                fixedPriceQuantity()
+                invoiceGroupingKey()
+                invoicingCycleConfiguration().map { it.validate() }
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24179,21 +31185,23 @@ constructor(
 
         class Builder {
 
-            private var cadence: Cadence? = null
-            private var currency: String? = null
-            private var groupedTieredPackageConfig: GroupedTieredPackageConfig? = null
-            private var itemId: String? = null
-            private var modelType: ModelType? = null
-            private var name: String? = null
-            private var billableMetricId: String? = null
-            private var billedInAdvance: Boolean? = null
-            private var billingCycleConfiguration: BillingCycleConfiguration? = null
-            private var conversionRate: Double? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var invoiceGroupingKey: String? = null
-            private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-            private var metadata: Metadata? = null
+            private var cadence: JsonField<Cadence>? = null
+            private var currency: JsonField<String>? = null
+            private var groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>? = null
+            private var itemId: JsonField<String>? = null
+            private var modelType: JsonField<ModelType>? = null
+            private var name: JsonField<String>? = null
+            private var billableMetricId: JsonField<String> = JsonMissing.of()
+            private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                JsonMissing.of()
+            private var conversionRate: JsonField<Double> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+            private var invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24223,30 +31231,45 @@ constructor(
             }
 
             /** The cadence to bill for this price on. */
-            fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+            fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+            /** The cadence to bill for this price on. */
+            fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
             /** An ISO 4217 currency string for which this price is billed in. */
-            fun currency(currency: String) = apply { this.currency = currency }
+            fun currency(currency: String) = currency(JsonField.of(currency))
+
+            /** An ISO 4217 currency string for which this price is billed in. */
+            fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
             fun groupedTieredPackageConfig(groupedTieredPackageConfig: GroupedTieredPackageConfig) =
-                apply {
-                    this.groupedTieredPackageConfig = groupedTieredPackageConfig
-                }
+                groupedTieredPackageConfig(JsonField.of(groupedTieredPackageConfig))
+
+            fun groupedTieredPackageConfig(
+                groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>
+            ) = apply { this.groupedTieredPackageConfig = groupedTieredPackageConfig }
+
+            /** The id of the item the plan will be associated with. */
+            fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
             /** The id of the item the plan will be associated with. */
-            fun itemId(itemId: String) = apply { this.itemId = itemId }
+            fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+            fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-            fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+            fun modelType(modelType: JsonField<ModelType>) = apply { this.modelType = modelType }
 
             /** The name of the price. */
-            fun name(name: String) = apply { this.name = name }
+            fun name(name: String) = name(JsonField.of(name))
+
+            /** The name of the price. */
+            fun name(name: JsonField<String>) = apply { this.name = name }
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
              */
-            fun billableMetricId(billableMetricId: String?) = apply {
-                this.billableMetricId = billableMetricId
-            }
+            fun billableMetricId(billableMetricId: String?) =
+                billableMetricId(JsonField.ofNullable(billableMetricId))
 
             /**
              * The id of the billable metric for the price. Only needed if the price is usage-based.
@@ -24254,13 +31277,19 @@ constructor(
             fun billableMetricId(billableMetricId: Optional<String>) =
                 billableMetricId(billableMetricId.orElse(null))
 
+            /**
+             * The id of the billable metric for the price. Only needed if the price is usage-based.
+             */
+            fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                this.billableMetricId = billableMetricId
+            }
+
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
              * true, and in-arrears if this is false.
              */
-            fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                this.billedInAdvance = billedInAdvance
-            }
+            fun billedInAdvance(billedInAdvance: Boolean?) =
+                billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
             /**
              * If the Price represents a fixed cost, the price will be billed in-advance if this is
@@ -24277,13 +31306,19 @@ constructor(
             fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                 billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+            /**
+             * If the Price represents a fixed cost, the price will be billed in-advance if this is
+             * true, and in-arrears if this is false.
+             */
+            fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                this.billedInAdvance = billedInAdvance
+            }
+
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
              */
             fun billingCycleConfiguration(billingCycleConfiguration: BillingCycleConfiguration?) =
-                apply {
-                    this.billingCycleConfiguration = billingCycleConfiguration
-                }
+                billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
             /**
              * For custom cadence: specifies the duration of the billing period in days or months.
@@ -24292,10 +31327,16 @@ constructor(
                 billingCycleConfiguration: Optional<BillingCycleConfiguration>
             ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+            /**
+             * For custom cadence: specifies the duration of the billing period in days or months.
+             */
+            fun billingCycleConfiguration(
+                billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+            ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
             /** The per unit conversion rate of the price currency to the invoicing currency. */
-            fun conversionRate(conversionRate: Double?) = apply {
-                this.conversionRate = conversionRate
-            }
+            fun conversionRate(conversionRate: Double?) =
+                conversionRate(JsonField.ofNullable(conversionRate))
 
             /** The per unit conversion rate of the price currency to the invoicing currency. */
             fun conversionRate(conversionRate: Double) = conversionRate(conversionRate as Double?)
@@ -24305,21 +31346,29 @@ constructor(
             fun conversionRate(conversionRate: Optional<Double>) =
                 conversionRate(conversionRate.orElse(null) as Double?)
 
-            /** An alias for the price. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
+            /** The per unit conversion rate of the price currency to the invoicing currency. */
+            fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                this.conversionRate = conversionRate
             }
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
+
             /** An alias for the price. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** An alias for the price. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
              */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
-            }
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
             /**
              * If the Price represents a fixed cost, this represents the quantity of units applied.
@@ -24334,22 +31383,33 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-            /** The property used to group this price on an invoice */
-            fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                this.invoiceGroupingKey = invoiceGroupingKey
+            /**
+             * If the Price represents a fixed cost, this represents the quantity of units applied.
+             */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
             }
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
             /** The property used to group this price on an invoice */
             fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                 invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+            /** The property used to group this price on an invoice */
+            fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                this.invoiceGroupingKey = invoiceGroupingKey
+            }
+
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
              * unspecified, a single invoice is produced per billing cycle.
              */
             fun invoicingCycleConfiguration(
                 invoicingCycleConfiguration: InvoicingCycleConfiguration?
-            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+            ) = invoicingCycleConfiguration(JsonField.ofNullable(invoicingCycleConfiguration))
 
             /**
              * Within each billing cycle, specifies the cadence at which invoices are produced. If
@@ -24359,12 +31419,20 @@ constructor(
                 invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
             ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+            /**
+             * Within each billing cycle, specifies the cadence at which invoices are produced. If
+             * unspecified, a single invoice is produced per billing cycle.
+             */
+            fun invoicingCycleConfiguration(
+                invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+            ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -24373,6 +31441,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -24508,6 +31583,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): GroupedTieredPackageConfig = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -24625,22 +31708,44 @@ constructor(
         class BillingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
+
+            /** The unit of billing period duration. */
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): BillingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -24650,8 +31755,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24663,10 +31768,17 @@ constructor(
                 }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -24783,22 +31895,44 @@ constructor(
         class InvoicingCycleConfiguration
         @JsonCreator
         private constructor(
-            @JsonProperty("duration") private val duration: Long,
-            @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+            @JsonProperty("duration")
+            @ExcludeMissing
+            private val duration: JsonField<Long> = JsonMissing.of(),
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The duration of the billing period. */
-            @JsonProperty("duration") fun duration(): Long = duration
+            fun duration(): Long = duration.getRequired("duration")
+
+            /** The unit of billing period duration. */
+            fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+            /** The duration of the billing period. */
+            @JsonProperty("duration") @ExcludeMissing fun _duration(): JsonField<Long> = duration
 
             /** The unit of billing period duration. */
-            @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+            @JsonProperty("duration_unit")
+            @ExcludeMissing
+            fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): InvoicingCycleConfiguration = apply {
+                if (!validated) {
+                    duration()
+                    durationUnit()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -24808,8 +31942,8 @@ constructor(
 
             class Builder {
 
-                private var duration: Long? = null
-                private var durationUnit: DurationUnit? = null
+                private var duration: JsonField<Long>? = null
+                private var durationUnit: JsonField<DurationUnit>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -24822,10 +31956,17 @@ constructor(
                     }
 
                 /** The duration of the billing period. */
-                fun duration(duration: Long) = apply { this.duration = duration }
+                fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                /** The duration of the billing period. */
+                fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                /** The unit of billing period duration. */
+                fun durationUnit(durationUnit: DurationUnit) =
+                    durationUnit(JsonField.of(durationUnit))
 
                 /** The unit of billing period duration. */
-                fun durationUnit(durationUnit: DurationUnit) = apply {
+                fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                     this.durationUnit = durationUnit
                 }
 
@@ -24951,6 +32092,14 @@ constructor(
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Metadata = apply {
+                if (!validated) {
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateParams.kt
index 85f0b877..48bff5b7 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,25 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to evaluate the output of a price for a given customer and time range. It
+ * enables filtering and grouping the output using
+ * [computed properties](../guides/extensibility/advanced-metrics#computed-properties), supporting
+ * the following workflows:
+ * 1. Showing detailed usage and costs to the end customer.
+ * 2. Auditing subtotals on invoice line items.
+ *
+ * For these workflows, the expressiveness of computed properties in both the filters and grouping
+ * is critical. For example, if you'd like to show your customer their usage grouped by hour and
+ * another property, you can do so with the following `grouping_keys`:
+ * `["hour_floor_timestamp_millis(timestamp_millis)", "my_property"]`. If you'd like to examine a
+ * customer's usage for a specific property value, you can do so with the following `filter`:
+ * `my_property = 'foo' AND my_other_property = 'bar'`.
+ *
+ * By default, the start of the time range must be no more than 100 days ago and the length of the
+ * results must be no greater than 1000. Note that this is a POST endpoint rather than a GET
+ * endpoint because it employs a JSON body rather than query parameters.
+ */
 class PriceEvaluateParams
 constructor(
     private val priceId: String,
@@ -52,12 +73,37 @@ constructor(
      */
     fun groupingKeys(): Optional<List<String>> = body.groupingKeys()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** The exclusive upper bound for event timestamps */
+    fun _timeframeEnd(): JsonField<OffsetDateTime> = body._timeframeEnd()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** The inclusive lower bound for event timestamps */
+    fun _timeframeStart(): JsonField<OffsetDateTime> = body._timeframeStart()
+
+    /** The ID of the customer to which this evaluation is scoped. */
+    fun _customerId(): JsonField<String> = body._customerId()
+
+    /** The external customer ID of the customer to which this evaluation is scoped. */
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    /**
+     * A boolean [computed property](../guides/extensibility/advanced-metrics#computed-properties)
+     * used to filter the underlying billable metric
+     */
+    fun _filter(): JsonField<String> = body._filter()
+
+    /**
+     * Properties (or
+     * [computed properties](../guides/extensibility/advanced-metrics#computed-properties)) used to
+     * group the underlying billable metric
+     */
+    fun _groupingKeys(): JsonField<List<String>> = body._groupingKeys()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): PriceEvaluateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -75,36 +121,83 @@ constructor(
     class PriceEvaluateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("timeframe_end") private val timeframeEnd: OffsetDateTime,
-        @JsonProperty("timeframe_start") private val timeframeStart: OffsetDateTime,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("filter") private val filter: String?,
-        @JsonProperty("grouping_keys") private val groupingKeys: List<String>?,
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        private val timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        private val timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("filter")
+        @ExcludeMissing
+        private val filter: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("grouping_keys")
+        @ExcludeMissing
+        private val groupingKeys: JsonField<List<String>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The exclusive upper bound for event timestamps */
-        @JsonProperty("timeframe_end") fun timeframeEnd(): OffsetDateTime = timeframeEnd
+        fun timeframeEnd(): OffsetDateTime = timeframeEnd.getRequired("timeframe_end")
 
         /** The inclusive lower bound for event timestamps */
-        @JsonProperty("timeframe_start") fun timeframeStart(): OffsetDateTime = timeframeStart
+        fun timeframeStart(): OffsetDateTime = timeframeStart.getRequired("timeframe_start")
+
+        /** The ID of the customer to which this evaluation is scoped. */
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /** The external customer ID of the customer to which this evaluation is scoped. */
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the underlying billable metric
+         */
+        fun filter(): Optional<String> = Optional.ofNullable(filter.getNullable("filter"))
+
+        /**
+         * Properties (or
+         * [computed properties](../guides/extensibility/advanced-metrics#computed-properties)) used
+         * to group the underlying billable metric
+         */
+        fun groupingKeys(): Optional<List<String>> =
+            Optional.ofNullable(groupingKeys.getNullable("grouping_keys"))
+
+        /** The exclusive upper bound for event timestamps */
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
+
+        /** The inclusive lower bound for event timestamps */
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         /** The ID of the customer to which this evaluation is scoped. */
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /** The external customer ID of the customer to which this evaluation is scoped. */
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         /**
          * A boolean
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
          * filter the underlying billable metric
          */
-        @JsonProperty("filter") fun filter(): Optional<String> = Optional.ofNullable(filter)
+        @JsonProperty("filter") @ExcludeMissing fun _filter(): JsonField<String> = filter
 
         /**
          * Properties (or
@@ -112,12 +205,27 @@ constructor(
          * to group the underlying billable metric
          */
         @JsonProperty("grouping_keys")
-        fun groupingKeys(): Optional<List<String>> = Optional.ofNullable(groupingKeys)
+        @ExcludeMissing
+        fun _groupingKeys(): JsonField<List<String>> = groupingKeys
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PriceEvaluateBody = apply {
+            if (!validated) {
+                timeframeEnd()
+                timeframeStart()
+                customerId()
+                externalCustomerId()
+                filter()
+                groupingKeys()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -127,12 +235,12 @@ constructor(
 
         class Builder {
 
-            private var timeframeEnd: OffsetDateTime? = null
-            private var timeframeStart: OffsetDateTime? = null
-            private var customerId: String? = null
-            private var externalCustomerId: String? = null
-            private var filter: String? = null
-            private var groupingKeys: MutableList<String>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var filter: JsonField<String> = JsonMissing.of()
+            private var groupingKeys: JsonField<MutableList<String>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -142,41 +250,56 @@ constructor(
                 customerId = priceEvaluateBody.customerId
                 externalCustomerId = priceEvaluateBody.externalCustomerId
                 filter = priceEvaluateBody.filter
-                groupingKeys = priceEvaluateBody.groupingKeys?.toMutableList()
+                groupingKeys = priceEvaluateBody.groupingKeys.map { it.toMutableList() }
                 additionalProperties = priceEvaluateBody.additionalProperties.toMutableMap()
             }
 
             /** The exclusive upper bound for event timestamps */
-            fun timeframeEnd(timeframeEnd: OffsetDateTime) = apply {
+            fun timeframeEnd(timeframeEnd: OffsetDateTime) =
+                timeframeEnd(JsonField.of(timeframeEnd))
+
+            /** The exclusive upper bound for event timestamps */
+            fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
                 this.timeframeEnd = timeframeEnd
             }
 
             /** The inclusive lower bound for event timestamps */
-            fun timeframeStart(timeframeStart: OffsetDateTime) = apply {
+            fun timeframeStart(timeframeStart: OffsetDateTime) =
+                timeframeStart(JsonField.of(timeframeStart))
+
+            /** The inclusive lower bound for event timestamps */
+            fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
                 this.timeframeStart = timeframeStart
             }
 
             /** The ID of the customer to which this evaluation is scoped. */
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             /** The ID of the customer to which this evaluation is scoped. */
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            /** The ID of the customer to which this evaluation is scoped. */
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /** The external customer ID of the customer to which this evaluation is scoped. */
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             /** The external customer ID of the customer to which this evaluation is scoped. */
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
+            /** The external customer ID of the customer to which this evaluation is scoped. */
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
+            }
+
             /**
              * A boolean
              * [computed property](../guides/extensibility/advanced-metrics#computed-properties)
              * used to filter the underlying billable metric
              */
-            fun filter(filter: String?) = apply { this.filter = filter }
+            fun filter(filter: String?) = filter(JsonField.ofNullable(filter))
 
             /**
              * A boolean
@@ -185,22 +308,28 @@ constructor(
              */
             fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+            /**
+             * A boolean
+             * [computed property](../guides/extensibility/advanced-metrics#computed-properties)
+             * used to filter the underlying billable metric
+             */
+            fun filter(filter: JsonField<String>) = apply { this.filter = filter }
+
             /**
              * Properties (or
              * [computed properties](../guides/extensibility/advanced-metrics#computed-properties))
              * used to group the underlying billable metric
              */
-            fun groupingKeys(groupingKeys: List<String>?) = apply {
-                this.groupingKeys = groupingKeys?.toMutableList()
-            }
+            fun groupingKeys(groupingKeys: List<String>) = groupingKeys(JsonField.of(groupingKeys))
 
             /**
              * Properties (or
              * [computed properties](../guides/extensibility/advanced-metrics#computed-properties))
              * used to group the underlying billable metric
              */
-            fun groupingKeys(groupingKeys: Optional<List<String>>) =
-                groupingKeys(groupingKeys.orElse(null))
+            fun groupingKeys(groupingKeys: JsonField<List<String>>) = apply {
+                this.groupingKeys = groupingKeys.map { it.toMutableList() }
+            }
 
             /**
              * Properties (or
@@ -208,7 +337,16 @@ constructor(
              * used to group the underlying billable metric
              */
             fun addGroupingKey(groupingKey: String) = apply {
-                groupingKeys = (groupingKeys ?: mutableListOf()).apply { add(groupingKey) }
+                groupingKeys =
+                    (groupingKeys ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(groupingKey)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -237,7 +375,7 @@ constructor(
                     customerId,
                     externalCustomerId,
                     filter,
-                    groupingKeys?.toImmutable(),
+                    (groupingKeys ?: JsonMissing.of()).map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -288,17 +426,30 @@ constructor(
         /** The exclusive upper bound for event timestamps */
         fun timeframeEnd(timeframeEnd: OffsetDateTime) = apply { body.timeframeEnd(timeframeEnd) }
 
+        /** The exclusive upper bound for event timestamps */
+        fun timeframeEnd(timeframeEnd: JsonField<OffsetDateTime>) = apply {
+            body.timeframeEnd(timeframeEnd)
+        }
+
         /** The inclusive lower bound for event timestamps */
         fun timeframeStart(timeframeStart: OffsetDateTime) = apply {
             body.timeframeStart(timeframeStart)
         }
 
+        /** The inclusive lower bound for event timestamps */
+        fun timeframeStart(timeframeStart: JsonField<OffsetDateTime>) = apply {
+            body.timeframeStart(timeframeStart)
+        }
+
         /** The ID of the customer to which this evaluation is scoped. */
         fun customerId(customerId: String?) = apply { body.customerId(customerId) }
 
         /** The ID of the customer to which this evaluation is scoped. */
         fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+        /** The ID of the customer to which this evaluation is scoped. */
+        fun customerId(customerId: JsonField<String>) = apply { body.customerId(customerId) }
+
         /** The external customer ID of the customer to which this evaluation is scoped. */
         fun externalCustomerId(externalCustomerId: String?) = apply {
             body.externalCustomerId(externalCustomerId)
@@ -308,6 +459,11 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        /** The external customer ID of the customer to which this evaluation is scoped. */
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         /**
          * A boolean
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
@@ -322,20 +478,28 @@ constructor(
          */
         fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+        /**
+         * A boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties) used to
+         * filter the underlying billable metric
+         */
+        fun filter(filter: JsonField<String>) = apply { body.filter(filter) }
+
         /**
          * Properties (or
          * [computed properties](../guides/extensibility/advanced-metrics#computed-properties)) used
          * to group the underlying billable metric
          */
-        fun groupingKeys(groupingKeys: List<String>?) = apply { body.groupingKeys(groupingKeys) }
+        fun groupingKeys(groupingKeys: List<String>) = apply { body.groupingKeys(groupingKeys) }
 
         /**
          * Properties (or
          * [computed properties](../guides/extensibility/advanced-metrics#computed-properties)) used
          * to group the underlying billable metric
          */
-        fun groupingKeys(groupingKeys: Optional<List<String>>) =
-            groupingKeys(groupingKeys.orElse(null))
+        fun groupingKeys(groupingKeys: JsonField<List<String>>) = apply {
+            body.groupingKeys(groupingKeys)
+        }
 
         /**
          * Properties (or
@@ -344,6 +508,25 @@ constructor(
          */
         fun addGroupingKey(groupingKey: String) = apply { body.addGroupingKey(groupingKey) }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -442,25 +625,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PriceEvaluateParams =
             PriceEvaluateParams(
                 checkNotNull(priceId) { "`priceId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateResponse.kt
index 60f9be4c..a90473e8 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceEvaluateResponse.kt
@@ -27,7 +27,7 @@ private constructor(
 
     fun data(): List<EvaluatePriceGroup> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<EvaluatePriceGroup>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -51,18 +51,33 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<EvaluatePriceGroup>> = JsonMissing.of()
+        private var data: JsonField<MutableList<EvaluatePriceGroup>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(priceEvaluateResponse: PriceEvaluateResponse) = apply {
-            data = priceEvaluateResponse.data
+            data = priceEvaluateResponse.data.map { it.toMutableList() }
             additionalProperties = priceEvaluateResponse.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<EvaluatePriceGroup>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<EvaluatePriceGroup>>) = apply { this.data = data }
+        fun data(data: JsonField<List<EvaluatePriceGroup>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: EvaluatePriceGroup) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -84,7 +99,11 @@ private constructor(
         }
 
         fun build(): PriceEvaluateResponse =
-            PriceEvaluateResponse(data.map { it.toImmutable() }, additionalProperties.toImmutable())
+            PriceEvaluateResponse(
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
+                additionalProperties.toImmutable()
+            )
     }
 
     override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdFetchParams.kt
index 532272eb..5fc55321 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdFetchParams.kt
@@ -7,6 +7,11 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint returns a price given an external price id. See the
+ * [price creation API](../reference/create-price) for more information about external price
+ * aliases.
+ */
 class PriceExternalPriceIdFetchParams
 constructor(
     private val externalPriceId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdUpdateParams.kt
index 6544f8b4..6c718353 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceExternalPriceIdUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,10 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to update the `metadata` property on a price. If you pass null for the
+ * metadata value, it will clear any existing metadata for that price.
+ */
 class PriceExternalPriceIdUpdateParams
 constructor(
     private val externalPriceId: String,
@@ -33,12 +39,19 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): PriceExternalPriceIdUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -56,7 +69,9 @@ constructor(
     class PriceExternalPriceIdUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -66,12 +81,28 @@ constructor(
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PriceExternalPriceIdUpdateBody = apply {
+            if (!validated) {
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -81,7 +112,7 @@ constructor(
 
         class Builder {
 
-            private var metadata: Metadata? = null
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -97,7 +128,7 @@ constructor(
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -106,6 +137,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -191,6 +229,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -289,25 +353,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PriceExternalPriceIdUpdateParams =
             PriceExternalPriceIdUpdateParams(
                 checkNotNull(externalPriceId) { "`externalPriceId` is required but was not set" },
@@ -334,6 +379,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceFetchParams.kt
index 8272d633..49d820b1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceFetchParams.kt
@@ -7,6 +7,7 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/** This endpoint returns a price given an identifier. */
 class PriceFetchParams
 constructor(
     private val priceId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceListParams.kt
index c6492f28..9d144c9c 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceListParams.kt
@@ -8,6 +8,10 @@ import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to list all add-on prices created using the
+ * [price creation endpoint](../reference/create-price).
+ */
 class PriceListParams
 constructor(
     private val cursor: String?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceUpdateParams.kt
index 1ed43b2b..b819ba84 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/PriceUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,10 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint allows you to update the `metadata` property on a price. If you pass null for the
+ * metadata value, it will clear any existing metadata for that price.
+ */
 class PriceUpdateParams
 constructor(
     private val priceId: String,
@@ -33,12 +39,19 @@ constructor(
      */
     fun metadata(): Optional<Metadata> = body.metadata()
 
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): PriceUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -56,7 +69,9 @@ constructor(
     class PriceUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("metadata") private val metadata: Metadata?,
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -66,12 +81,28 @@ constructor(
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): PriceUpdateBody = apply {
+            if (!validated) {
+                metadata().map { it.validate() }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -81,7 +112,7 @@ constructor(
 
         class Builder {
 
-            private var metadata: Metadata? = null
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -95,7 +126,7 @@ constructor(
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -104,6 +135,13 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -184,6 +222,32 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -282,25 +346,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): PriceUpdateParams =
             PriceUpdateParams(
                 checkNotNull(priceId) { "`priceId` is required but was not set" },
@@ -327,6 +372,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscription.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscription.kt
index 9a6688ed..6d7de6d7 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscription.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscription.kt
@@ -260,37 +260,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -299,7 +306,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -308,7 +315,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -328,7 +335,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -336,60 +343,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -437,40 +457,40 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(subscription: Subscription) = apply {
             id = subscription.id
             activePlanPhaseOrder = subscription.activePlanPhaseOrder
-            adjustmentIntervals = subscription.adjustmentIntervals
+            adjustmentIntervals = subscription.adjustmentIntervals.map { it.toMutableList() }
             autoCollection = subscription.autoCollection
             billingCycleAnchorConfiguration = subscription.billingCycleAnchorConfiguration
             billingCycleDay = subscription.billingCycleDay
@@ -479,16 +499,17 @@ private constructor(
             currentBillingPeriodStartDate = subscription.currentBillingPeriodStartDate
             customer = subscription.customer
             defaultInvoiceMemo = subscription.defaultInvoiceMemo
-            discountIntervals = subscription.discountIntervals
+            discountIntervals = subscription.discountIntervals.map { it.toMutableList() }
             endDate = subscription.endDate
-            fixedFeeQuantitySchedule = subscription.fixedFeeQuantitySchedule
+            fixedFeeQuantitySchedule =
+                subscription.fixedFeeQuantitySchedule.map { it.toMutableList() }
             invoicingThreshold = subscription.invoicingThreshold
-            maximumIntervals = subscription.maximumIntervals
+            maximumIntervals = subscription.maximumIntervals.map { it.toMutableList() }
             metadata = subscription.metadata
-            minimumIntervals = subscription.minimumIntervals
+            minimumIntervals = subscription.minimumIntervals.map { it.toMutableList() }
             netTerms = subscription.netTerms
             plan = subscription.plan
-            priceIntervals = subscription.priceIntervals
+            priceIntervals = subscription.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscription.redeemedCoupon
             startDate = subscription.startDate
             status = subscription.status
@@ -500,9 +521,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -515,15 +545,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -569,8 +630,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -587,8 +656,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -643,8 +720,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -660,11 +744,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -674,10 +775,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -689,7 +809,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -712,7 +846,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -751,11 +899,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -796,31 +961,55 @@ private constructor(
 
         fun build(): Subscription =
             Subscription(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -861,20 +1050,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -902,18 +1097,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -929,6 +1125,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -936,11 +1147,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -974,11 +1203,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1281,11 +1513,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1293,12 +1525,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1306,15 +1538,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1344,13 +1576,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1358,7 +1590,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1398,7 +1631,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1416,9 +1663,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1426,7 +1682,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1455,13 +1714,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1593,16 +1863,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1610,7 +1880,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1618,15 +1888,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1656,13 +1926,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1670,7 +1940,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1696,7 +1969,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1729,9 +2016,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1739,7 +2035,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1768,13 +2067,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1905,16 +2215,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1922,21 +2232,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1966,20 +2278,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -2005,7 +2318,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2023,9 +2350,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2033,7 +2369,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2077,13 +2416,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2220,16 +2570,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2237,24 +2587,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2285,21 +2637,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2325,7 +2678,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2364,9 +2731,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2374,7 +2750,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2403,14 +2782,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2541,16 +2931,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2558,21 +2948,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2602,20 +2994,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2640,7 +3033,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2673,9 +3080,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2683,7 +3099,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2712,13 +3131,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2851,19 +3281,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2889,7 +3319,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2924,7 +3354,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2936,7 +3379,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2965,7 +3421,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3217,25 +3673,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3264,19 +3728,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3299,7 +3765,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3309,9 +3789,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3320,7 +3815,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3357,12 +3855,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3485,25 +3991,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3532,18 +4044,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3558,7 +4074,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3568,9 +4098,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3579,7 +4124,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3629,12 +4177,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3760,26 +4316,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3808,18 +4372,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3833,7 +4399,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3843,9 +4423,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3854,7 +4449,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3906,12 +4504,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4015,13 +4621,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4048,10 +4658,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4063,7 +4673,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4102,10 +4714,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4175,24 +4787,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4220,17 +4838,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4243,7 +4862,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4253,11 +4886,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4305,11 +4956,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4459,24 +5116,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4504,17 +5167,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4527,7 +5191,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4537,11 +5215,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4589,11 +5285,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4928,10 +5630,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4940,7 +5644,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4949,13 +5653,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4963,7 +5670,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5193,13 +5901,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5230,15 +5940,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5248,7 +5959,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5272,8 +5984,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5289,8 +6009,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5305,7 +6034,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5318,8 +6053,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5327,7 +6070,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5789,6 +6554,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5824,14 +6654,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5859,11 +6698,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5889,9 +6730,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5942,9 +6783,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6009,11 +6852,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6039,9 +6886,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6056,7 +6903,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6087,9 +6936,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6189,7 +7038,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6213,7 +7064,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6222,7 +7073,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6245,7 +7098,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelParams.kt
index 3fd4cb69..40c49b19 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -20,6 +21,57 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to cancel an existing subscription. It returns the serialized
+ * subscription object with an `end_date` parameter that signifies when the subscription will
+ * transition to an ended state.
+ *
+ * The body parameter `cancel_option` determines the cancellation behavior. Orb supports three
+ * cancellation options:
+ * - `end_of_subscription_term`: stops the subscription from auto-renewing. Subscriptions that have
+ *   been cancelled with this option can still incur charges for the remainder of their term:
+ *     - Issuing this cancellation request for a monthly subscription will keep the subscription
+ *       active until the start of the subsequent month, and potentially issue an invoice for any
+ *       usage charges incurred in the intervening period.
+ *     - Issuing this cancellation request for a quarterly subscription will keep the subscription
+ *       active until the end of the quarter and potentially issue an invoice for any usage charges
+ *       incurred in the intervening period.
+ *     - Issuing this cancellation request for a yearly subscription will keep the subscription
+ *       active for the full year. For example, a yearly subscription starting on 2021-11-01 and
+ *       cancelled on 2021-12-08 will remain active until 2022-11-01 and potentially issue charges
+ *       in the intervening months for any recurring monthly usage charges in its plan.
+ *     - **Note**: If a subscription's plan contains prices with difference cadences, the end of
+ *       term date will be determined by the largest cadence value. For example, cancelling end of
+ *       term for a subscription with a quarterly fixed fee with a monthly usage fee will result in
+ *       the subscription ending at the end of the quarter.
+ * - `immediate`: ends the subscription immediately, setting the `end_date` to the current time:
+ *     - Subscriptions that have been cancelled with this option will be invoiced immediately. This
+ *       invoice will include any usage fees incurred in the billing period up to the cancellation,
+ *       along with any prorated recurring fees for the billing period, if applicable.
+ *     - **Note**: If the subscription has a recurring fee that was paid in-advance, the prorated
+ *       amount for the remaining time period will be added to the
+ *       [customer's balance](list-balance-transactions) upon immediate cancellation. However, if
+ *       the customer is ineligible to use the customer balance, the subscription cannot be
+ *       cancelled immediately.
+ * - `requested_date`: ends the subscription on a specified date, which requires a
+ *   `cancellation_date` to be passed in. If no timezone is provided, the customer's timezone is
+ *   used. For example, a subscription starting on January 1st with a monthly price can be set to be
+ *   cancelled on the first of any month after January 1st (e.g. March 1st, April 1st, May 1st). A
+ *   subscription with multiple prices with different cadences defines the "term" to be the highest
+ *   cadence of the prices.
+ *
+ * Upcoming subscriptions are only eligible for immediate cancellation, which will set the
+ * `end_date` equal to the `start_date` upon cancellation.
+ *
+ * ## Backdated cancellations
+ *
+ * Orb allows you to cancel a subscription in the past as long as there are no paid invoices between
+ * the `requested_date` and the current time. If the cancellation is after the latest issued
+ * invoice, Orb will generate a balance refund for the current period. If the cancellation is before
+ * the most recently issued invoice, Orb will void the intervening invoice and generate a new one
+ * based on the new dates for the subscription. See the section on
+ * [cancellation behaviors](../guides/product-catalog/creating-subscriptions.md#cancellation-behaviors).
+ */
 class SubscriptionCancelParams
 constructor(
     private val subscriptionId: String,
@@ -39,12 +91,21 @@ constructor(
      */
     fun cancellationDate(): Optional<OffsetDateTime> = body.cancellationDate()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** Determines the timing of subscription cancellation */
+    fun _cancelOption(): JsonField<CancelOption> = body._cancelOption()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * The date that the cancellation should take effect. This parameter can only be passed if the
+     * `cancel_option` is `requested_date`.
+     */
+    fun _cancellationDate(): JsonField<OffsetDateTime> = body._cancellationDate()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionCancelBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -62,26 +123,53 @@ constructor(
     class SubscriptionCancelBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("cancel_option") private val cancelOption: CancelOption,
-        @JsonProperty("cancellation_date") private val cancellationDate: OffsetDateTime?,
+        @JsonProperty("cancel_option")
+        @ExcludeMissing
+        private val cancelOption: JsonField<CancelOption> = JsonMissing.of(),
+        @JsonProperty("cancellation_date")
+        @ExcludeMissing
+        private val cancellationDate: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** Determines the timing of subscription cancellation */
-        @JsonProperty("cancel_option") fun cancelOption(): CancelOption = cancelOption
+        fun cancelOption(): CancelOption = cancelOption.getRequired("cancel_option")
+
+        /**
+         * The date that the cancellation should take effect. This parameter can only be passed if
+         * the `cancel_option` is `requested_date`.
+         */
+        fun cancellationDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(cancellationDate.getNullable("cancellation_date"))
+
+        /** Determines the timing of subscription cancellation */
+        @JsonProperty("cancel_option")
+        @ExcludeMissing
+        fun _cancelOption(): JsonField<CancelOption> = cancelOption
 
         /**
          * The date that the cancellation should take effect. This parameter can only be passed if
          * the `cancel_option` is `requested_date`.
          */
         @JsonProperty("cancellation_date")
-        fun cancellationDate(): Optional<OffsetDateTime> = Optional.ofNullable(cancellationDate)
+        @ExcludeMissing
+        fun _cancellationDate(): JsonField<OffsetDateTime> = cancellationDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionCancelBody = apply {
+            if (!validated) {
+                cancelOption()
+                cancellationDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -91,8 +179,8 @@ constructor(
 
         class Builder {
 
-            private var cancelOption: CancelOption? = null
-            private var cancellationDate: OffsetDateTime? = null
+            private var cancelOption: JsonField<CancelOption>? = null
+            private var cancellationDate: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -103,7 +191,10 @@ constructor(
             }
 
             /** Determines the timing of subscription cancellation */
-            fun cancelOption(cancelOption: CancelOption) = apply {
+            fun cancelOption(cancelOption: CancelOption) = cancelOption(JsonField.of(cancelOption))
+
+            /** Determines the timing of subscription cancellation */
+            fun cancelOption(cancelOption: JsonField<CancelOption>) = apply {
                 this.cancelOption = cancelOption
             }
 
@@ -111,9 +202,8 @@ constructor(
              * The date that the cancellation should take effect. This parameter can only be passed
              * if the `cancel_option` is `requested_date`.
              */
-            fun cancellationDate(cancellationDate: OffsetDateTime?) = apply {
-                this.cancellationDate = cancellationDate
-            }
+            fun cancellationDate(cancellationDate: OffsetDateTime?) =
+                cancellationDate(JsonField.ofNullable(cancellationDate))
 
             /**
              * The date that the cancellation should take effect. This parameter can only be passed
@@ -122,6 +212,14 @@ constructor(
             fun cancellationDate(cancellationDate: Optional<OffsetDateTime>) =
                 cancellationDate(cancellationDate.orElse(null))
 
+            /**
+             * The date that the cancellation should take effect. This parameter can only be passed
+             * if the `cancel_option` is `requested_date`.
+             */
+            fun cancellationDate(cancellationDate: JsonField<OffsetDateTime>) = apply {
+                this.cancellationDate = cancellationDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -195,6 +293,11 @@ constructor(
         /** Determines the timing of subscription cancellation */
         fun cancelOption(cancelOption: CancelOption) = apply { body.cancelOption(cancelOption) }
 
+        /** Determines the timing of subscription cancellation */
+        fun cancelOption(cancelOption: JsonField<CancelOption>) = apply {
+            body.cancelOption(cancelOption)
+        }
+
         /**
          * The date that the cancellation should take effect. This parameter can only be passed if
          * the `cancel_option` is `requested_date`.
@@ -210,6 +313,33 @@ constructor(
         fun cancellationDate(cancellationDate: Optional<OffsetDateTime>) =
             cancellationDate(cancellationDate.orElse(null))
 
+        /**
+         * The date that the cancellation should take effect. This parameter can only be passed if
+         * the `cancel_option` is `requested_date`.
+         */
+        fun cancellationDate(cancellationDate: JsonField<OffsetDateTime>) = apply {
+            body.cancellationDate(cancellationDate)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -308,25 +438,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionCancelParams =
             SubscriptionCancelParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelResponse.kt
index 6ce3c360..d81c38b4 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCancelResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,40 +439,41 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(subscriptionCancelResponse: SubscriptionCancelResponse) = apply {
             id = subscriptionCancelResponse.id
             activePlanPhaseOrder = subscriptionCancelResponse.activePlanPhaseOrder
-            adjustmentIntervals = subscriptionCancelResponse.adjustmentIntervals
+            adjustmentIntervals =
+                subscriptionCancelResponse.adjustmentIntervals.map { it.toMutableList() }
             autoCollection = subscriptionCancelResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionCancelResponse.billingCycleAnchorConfiguration
@@ -462,16 +483,20 @@ private constructor(
             currentBillingPeriodStartDate = subscriptionCancelResponse.currentBillingPeriodStartDate
             customer = subscriptionCancelResponse.customer
             defaultInvoiceMemo = subscriptionCancelResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionCancelResponse.discountIntervals
+            discountIntervals =
+                subscriptionCancelResponse.discountIntervals.map { it.toMutableList() }
             endDate = subscriptionCancelResponse.endDate
-            fixedFeeQuantitySchedule = subscriptionCancelResponse.fixedFeeQuantitySchedule
+            fixedFeeQuantitySchedule =
+                subscriptionCancelResponse.fixedFeeQuantitySchedule.map { it.toMutableList() }
             invoicingThreshold = subscriptionCancelResponse.invoicingThreshold
-            maximumIntervals = subscriptionCancelResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionCancelResponse.maximumIntervals.map { it.toMutableList() }
             metadata = subscriptionCancelResponse.metadata
-            minimumIntervals = subscriptionCancelResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionCancelResponse.minimumIntervals.map { it.toMutableList() }
             netTerms = subscriptionCancelResponse.netTerms
             plan = subscriptionCancelResponse.plan
-            priceIntervals = subscriptionCancelResponse.priceIntervals
+            priceIntervals = subscriptionCancelResponse.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscriptionCancelResponse.redeemedCoupon
             startDate = subscriptionCancelResponse.startDate
             status = subscriptionCancelResponse.status
@@ -483,9 +508,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -498,15 +532,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -552,8 +617,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -570,8 +643,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -626,8 +707,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -643,11 +731,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -657,10 +762,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -672,7 +796,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -695,7 +833,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -734,11 +886,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -779,31 +948,55 @@ private constructor(
 
         fun build(): SubscriptionCancelResponse =
             SubscriptionCancelResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -844,20 +1037,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -885,18 +1084,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -912,6 +1112,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -919,11 +1134,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -957,11 +1190,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1264,11 +1500,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1276,12 +1512,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1289,15 +1525,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1327,13 +1563,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1341,7 +1577,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1381,7 +1618,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1399,9 +1650,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1409,7 +1669,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1438,13 +1701,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1576,16 +1850,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1593,7 +1867,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1601,15 +1875,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1639,13 +1913,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1653,7 +1927,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1679,7 +1956,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1712,9 +2003,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1722,7 +2022,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1751,13 +2054,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1888,16 +2202,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1905,21 +2219,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1949,20 +2265,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1988,7 +2305,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2006,9 +2337,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2016,7 +2356,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2060,13 +2403,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2203,16 +2557,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2220,24 +2574,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2268,21 +2624,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2308,7 +2665,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2347,9 +2718,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2357,7 +2737,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2386,14 +2769,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2524,16 +2918,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2541,21 +2935,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2585,20 +2981,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2623,7 +3020,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2656,9 +3067,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2666,7 +3086,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2695,13 +3118,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2834,19 +3268,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2872,7 +3306,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2907,7 +3341,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2919,7 +3366,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2948,7 +3408,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3200,25 +3660,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3247,19 +3715,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3282,7 +3752,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3292,9 +3776,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3303,7 +3802,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3340,12 +3842,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3468,25 +3978,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3515,18 +4031,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3541,7 +4061,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3551,9 +4085,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3562,7 +4111,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3612,12 +4164,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3743,26 +4303,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3791,18 +4359,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3816,7 +4386,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3826,9 +4410,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3837,7 +4436,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3889,12 +4491,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3998,13 +4608,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4031,10 +4645,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4046,7 +4660,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4085,10 +4701,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4158,24 +4774,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4203,17 +4825,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4226,7 +4849,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4236,11 +4873,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4288,11 +4943,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4442,24 +5103,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4487,17 +5154,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4510,7 +5178,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4520,11 +5202,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4572,11 +5272,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4911,10 +5617,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4923,7 +5631,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4932,13 +5640,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4946,7 +5657,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5176,13 +5888,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5213,15 +5927,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5231,7 +5946,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5255,8 +5971,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5272,8 +5996,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5288,7 +6021,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5301,8 +6040,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5310,7 +6057,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5772,6 +6541,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5807,14 +6641,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5842,11 +6685,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5872,9 +6717,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5925,9 +6770,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5992,11 +6839,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6022,9 +6873,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6039,7 +6890,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6070,9 +6923,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6172,7 +7025,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6196,7 +7051,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6205,7 +7060,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6228,7 +7085,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateParams.kt
index 0843d159..b02181a8 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -31,6 +32,236 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * A subscription represents the purchase of a plan by a customer. The customer is identified by
+ * either the `customer_id` or the `external_customer_id`, and exactly one of these fields must be
+ * provided.
+ *
+ * By default, subscriptions begin on the day that they're created and renew automatically for each
+ * billing cycle at the cadence that's configured in the plan definition.
+ *
+ * The default configuration for subscriptions in Orb is **In-advance billing** and **Beginning of
+ * month alignment** (see [Subscription](../guides/concepts#subscription) for more details).
+ *
+ * In order to change the alignment behavior, Orb also supports billing subscriptions on the day of
+ * the month they are created. If `align_billing_with_subscription_start_date = true` is specified,
+ * subscriptions have billing cycles that are aligned with their `start_date`. For example, a
+ * subscription that begins on January 15th will have a billing cycle from January 15th to February
+ * 15th. Every subsequent billing cycle will continue to start and invoice on the 15th.
+ *
+ * If the "day" value is greater than the number of days in the month, the next billing cycle will
+ * start at the end of the month. For example, if the start_date is January 31st, the next billing
+ * cycle will start on February 28th.
+ *
+ * If a customer was created with a currency, Orb only allows subscribing the customer to a plan
+ * with a matching `invoicing_currency`. If the customer does not have a currency set, on
+ * subscription creation, we set the customer's currency to be the `invoicing_currency` of the plan.
+ *
+ * ## Customize your customer's subscriptions
+ *
+ * Prices and adjustments in a plan can be added, removed, or replaced for the subscription being
+ * created. This is useful when a customer has prices that differ from the default prices for a
+ * specific plan.
+ *
+ * :::info This feature is only available for accounts that have migrated to Subscription Overrides
+ * Version 2. You can find your Subscription Overrides Version at the bottom of your
+ * [Plans page](https://app.withorb.com/plans) :::
+ *
+ * ### Adding Prices
+ *
+ * To add prices, provide a list of objects with the key `add_prices`. An object in the list must
+ * specify an existing add-on price with a `price_id` or `external_price_id` field, or create a new
+ * add-on price by including an object with the key `price`, identical to what would be used in the
+ * request body for the [create price endpoint](../reference/create-price). See the
+ * [Price resource](../reference/price) for the specification of different price model
+ * configurations possible in this object.
+ *
+ * If the plan has phases, each object in the list must include a number with `plan_phase_order` key
+ * to indicate which phase the price should be added to.
+ *
+ * An object in the list can specify an optional `start_date` and optional `end_date`. This is
+ * equivalent to creating a price interval with the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals). If unspecified, the
+ * start or end date of the phase or subscription will be used.
+ *
+ * An object in the list can specify an optional `minimum_amount`, `maximum_amount`, or `discounts`.
+ * This will create adjustments which apply only to this price.
+ *
+ * Additionally, an object in the list can specify an optional `reference_id`. This ID can be used
+ * to reference this price when [adding an adjustment](#adding-adjustments) in the same API call.
+ * However the ID is _transient_ and cannot be used to refer to the price in future API calls.
+ *
+ * ### Removing Prices
+ *
+ * To remove prices, provide a list of objects with the key `remove_prices`. An object in the list
+ * must specify a plan price with either a `price_id` or `external_price_id` field.
+ *
+ * ### Replacing Prices
+ *
+ * To replace prices, provide a list of objects with the key `replace_prices`. An object in the list
+ * must specify a plan price to replace with the `replaces_price_id` key, and it must specify a
+ * price to replace it with by either referencing an existing add-on price with a `price_id` or
+ * `external_price_id` field, or by creating a new add-on price by including an object with the key
+ * `price`, identical to what would be used in the request body for the
+ * [create price endpoint](../reference/create-price). See the [Price resource](../reference/price)
+ * for the specification of different price model configurations possible in this object.
+ *
+ * For fixed fees, an object in the list can supply a `fixed_price_quantity` instead of a `price`,
+ * `price_id`, or `external_price_id` field. This will update only the quantity for the price,
+ * similar to the [Update price quantity](../reference/update-fixed-fee-quantity) endpoint.
+ *
+ * The replacement price will have the same phase, if applicable, and the same start and end dates
+ * as the price it replaces.
+ *
+ * An object in the list can specify an optional `minimum_amount`, `maximum_amount`, or `discounts`.
+ * This will create adjustments which apply only to this price.
+ *
+ * Additionally, an object in the list can specify an optional `reference_id`. This ID can be used
+ * to reference the replacement price when [adding an adjustment](#adding-adjustments) in the same
+ * API call. However the ID is _transient_ and cannot be used to refer to the price in future API
+ * calls.
+ *
+ * ### Adding adjustments
+ *
+ * To add adjustments, provide a list of objects with the key `add_adjustments`. An object in the
+ * list must include an object with the key `adjustment`, identical to the adjustment object in the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals).
+ *
+ * If the plan has phases, each object in the list must include a number with `plan_phase_order` key
+ * to indicate which phase the adjustment should be added to.
+ *
+ * An object in the list can specify an optional `start_date` and optional `end_date`. If
+ * unspecified, the start or end date of the phase or subscription will be used.
+ *
+ * ### Removing adjustments
+ *
+ * To remove adjustments, provide a list of objects with the key `remove_adjustments`. An object in
+ * the list must include a key, `adjustment_id`, with the ID of the adjustment to be removed.
+ *
+ * ### Replacing adjustments
+ *
+ * To replace adjustments, provide a list of objects with the key `replace_adjustments`. An object
+ * in the list must specify a plan adjustment to replace with the `replaces_adjustment_id` key, and
+ * it must specify an adjustment to replace it with by including an object with the key
+ * `adjustment`, identical to the adjustment object in the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals).
+ *
+ * The replacement adjustment will have the same phase, if applicable, and the same start and end
+ * dates as the adjustment it replaces.
+ *
+ * ## Price overrides (DEPRECATED)
+ *
+ * :::info Price overrides are being phased out in favor adding/removing/replacing prices. (See
+ * [Customize your customer's subscriptions](../reference/create-subscription#customize-your-customers-subscriptions))
+ * :::
+ *
+ * Price overrides are used to update some or all prices in a plan for the specific subscription
+ * being created. This is useful when a new customer has negotiated a rate that is unique to the
+ * customer.
+ *
+ * To override prices, provide a list of objects with the key `price_overrides`. The price object in
+ * the list of overrides is expected to contain the existing price id, the `model_type` and
+ * configuration. (See the [Price resource](../reference/price) for the specification of different
+ * price model configurations.) The numerical values can be updated, but the billable metric,
+ * cadence, type, and name of a price can not be overridden.
+ *
+ * ### Maximums and Minimums
+ *
+ * Minimums and maximums, much like price overrides, can be useful when a new customer has
+ * negotiated a new or different minimum or maximum spend cap than the default for a given price. If
+ * one exists for a price and null is provided for the minimum/maximum override on creation, then
+ * there will be no minimum/maximum on the new subscription. If no value is provided, then the
+ * default price maximum or minimum is used.
+ *
+ * To add a minimum for a specific price, add `minimum_amount` to the specific price in the
+ * `price_overrides` object.
+ *
+ * To add a maximum for a specific price, add `maximum_amount` to the specific price in the
+ * `price_overrides` object.
+ *
+ * ### Minimum override example
+ *
+ * Price minimum override example:
+ * ```json
+ * {
+ *   ...
+ *   "id": "price_id",
+ *   "model_type": "unit",
+ *   "unit_config": {
+ *     "unit_amount": "0.50"
+ *   },
+ *   "minimum_amount": "100.00"
+ *   ...
+ * }
+ * ```
+ *
+ * Removing an existing minimum example
+ *
+ * ```json
+ * {
+ *   ...
+ *   "id": "price_id",
+ *   "model_type": "unit",
+ *   "unit_config": {
+ *     "unit_amount": "0.50"
+ *   },
+ *   "minimum_amount": null
+ *   ...
+ * }
+ * ```
+ *
+ * ### Discounts
+ *
+ * Discounts, like price overrides, can be useful when a new customer has negotiated a new or
+ * different discount than the default for a price. If a discount exists for a price and a null
+ * discount is provided on creation, then there will be no discount on the new subscription.
+ *
+ * To add a discount for a specific price, add `discount` to the price in the `price_overrides`
+ * object. Discount should be a dictionary of the format:
+ * ```ts
+ * {
+ *   "discount_type": "amount" | "percentage" | "usage",
+ *   "amount_discount": string,
+ *   "percentage_discount": string,
+ *   "usage_discount": string
+ * }
+ * ```
+ *
+ * where either `amount_discount`, `percentage_discount`, or `usage_discount` is provided.
+ *
+ * Price discount example
+ *
+ * ```json
+ * {
+ *   ...
+ *   "id": "price_id",
+ *   "model_type": "unit",
+ *   "unit_config": {
+ *     "unit_amount": "0.50"
+ *   },
+ *   "discount": {"discount_type": "amount", "amount_discount": "175"},
+ * }
+ * ```
+ *
+ * Removing an existing discount example
+ *
+ * ```json
+ * {
+ *   "customer_id": "customer_id",
+ *   "plan_id": "plan_id",
+ *   "discount": null,
+ *   "price_overrides": [ ... ]
+ *   ...
+ * }
+ * ```
+ *
+ * ## Threshold Billing
+ *
+ * Orb supports invoicing for a subscription when a preconfigured usage threshold is hit. To enable
+ * threshold billing, pass in an `invoicing_threshold`, which is specified in the subscription's
+ * invoicing currency, when creating a subscription. E.g. pass in `10.00` to issue an invoice when
+ * usage amounts hit $10.00 for a subscription that invoices in USD.
+ */
 class SubscriptionCreateParams
 constructor(
     private val body: SubscriptionCreateBody,
@@ -176,12 +407,151 @@ constructor(
      */
     fun trialDurationDays(): Optional<Long> = body.trialDurationDays()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * Additional adjustments to be added to the subscription. (Only available for accounts that
+     * have migrated off of legacy subscription overrides)
+     */
+    fun _addAdjustments(): JsonField<List<AddAdjustment>> = body._addAdjustments()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Additional prices to be added to the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _addPrices(): JsonField<List<AddPrice>> = body._addPrices()
+
+    fun _alignBillingWithSubscriptionStartDate(): JsonField<Boolean> =
+        body._alignBillingWithSubscriptionStartDate()
+
+    /**
+     * Determines whether issued invoices for this subscription will automatically be charged with
+     * the saved payment method on the due date. If not specified, this defaults to the behavior
+     * configured for this customer.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
+
+    fun _awsRegion(): JsonField<String> = body._awsRegion()
+
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        body._billingCycleAnchorConfiguration()
+
+    /**
+     * Redemption code to be used for this subscription. If the coupon cannot be found by its
+     * redemption code, or cannot be redeemed, an error response will be returned and the
+     * subscription creation or plan change will not be scheduled.
+     */
+    fun _couponRedemptionCode(): JsonField<String> = body._couponRedemptionCode()
+
+    fun _creditsOverageRate(): JsonField<Double> = body._creditsOverageRate()
+
+    fun _customerId(): JsonField<String> = body._customerId()
+
+    /**
+     * Determines the default memo on this subscription's invoices. Note that if this is not
+     * provided, it is determined by the plan configuration.
+     */
+    fun _defaultInvoiceMemo(): JsonField<String> = body._defaultInvoiceMemo()
+
+    fun _endDate(): JsonField<OffsetDateTime> = body._endDate()
+
+    fun _externalCustomerId(): JsonField<String> = body._externalCustomerId()
+
+    fun _externalMarketplace(): JsonField<ExternalMarketplace> = body._externalMarketplace()
+
+    fun _externalMarketplaceReportingId(): JsonField<String> =
+        body._externalMarketplaceReportingId()
+
+    /**
+     * The external_plan_id of the plan that the given subscription should be switched to. Note that
+     * either this property or `plan_id` must be specified.
+     */
+    fun _externalPlanId(): JsonField<String> = body._externalPlanId()
+
+    /**
+     * An additional filter to apply to usage queries. This filter must be expressed as a boolean
+     * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If null,
+     * usage queries will not include any additional filter.
+     */
+    fun _filter(): JsonField<String> = body._filter()
+
+    /** The phase of the plan to start with */
+    fun _initialPhaseOrder(): JsonField<Long> = body._initialPhaseOrder()
+
+    /**
+     * When this subscription's accrued usage reaches this threshold, an invoice will be issued for
+     * the subscription. If not specified, invoices will only be issued at the end of the billing
+     * period.
+     */
+    fun _invoicingThreshold(): JsonField<String> = body._invoicingThreshold()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /**
+     * The net terms determines the difference between the invoice date and the issue date for the
+     * invoice. If you intend the invoice to be due on issue, set this to 0. If not provided, this
+     * defaults to the value specified in the plan.
+     */
+    fun _netTerms(): JsonField<Long> = body._netTerms()
+
+    fun _perCreditOverageAmount(): JsonField<Double> = body._perCreditOverageAmount()
+
+    /**
+     * The plan that the given subscription should be switched to. Note that either this property or
+     * `external_plan_id` must be specified.
+     */
+    fun _planId(): JsonField<String> = body._planId()
+
+    /**
+     * Specifies which version of the plan to subscribe to. If null, the default version will be
+     * used.
+     */
+    fun _planVersionNumber(): JsonField<Long> = body._planVersionNumber()
+
+    /** Optionally provide a list of overrides for prices on the plan */
+    fun _priceOverrides(): JsonField<List<JsonValue>> = body._priceOverrides()
+
+    /**
+     * Plan adjustments to be removed from the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _removeAdjustments(): JsonField<List<RemoveAdjustment>> = body._removeAdjustments()
+
+    /**
+     * Plan prices to be removed from the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _removePrices(): JsonField<List<RemovePrice>> = body._removePrices()
+
+    /**
+     * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+     * available for accounts that have migrated off of legacy subscription overrides)
+     */
+    fun _replaceAdjustments(): JsonField<List<ReplaceAdjustment>> = body._replaceAdjustments()
+
+    /**
+     * Plan prices to be replaced with additional prices on the subscription. (Only available for
+     * accounts that have migrated off of legacy subscription overrides)
+     */
+    fun _replacePrices(): JsonField<List<ReplacePrice>> = body._replacePrices()
+
+    fun _startDate(): JsonField<OffsetDateTime> = body._startDate()
+
+    /**
+     * The duration of the trial period in days. If not provided, this defaults to the value
+     * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+     */
+    fun _trialDurationDays(): JsonField<Long> = body._trialDurationDays()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionCreateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -192,61 +562,291 @@ constructor(
     class SubscriptionCreateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("add_adjustments") private val addAdjustments: List<AddAdjustment>?,
-        @JsonProperty("add_prices") private val addPrices: List<AddPrice>?,
+        @JsonProperty("add_adjustments")
+        @ExcludeMissing
+        private val addAdjustments: JsonField<List<AddAdjustment>> = JsonMissing.of(),
+        @JsonProperty("add_prices")
+        @ExcludeMissing
+        private val addPrices: JsonField<List<AddPrice>> = JsonMissing.of(),
         @JsonProperty("align_billing_with_subscription_start_date")
-        private val alignBillingWithSubscriptionStartDate: Boolean?,
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
-        @JsonProperty("aws_region") private val awsRegion: String?,
+        @ExcludeMissing
+        private val alignBillingWithSubscriptionStartDate: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("aws_region")
+        @ExcludeMissing
+        private val awsRegion: JsonField<String> = JsonMissing.of(),
         @JsonProperty("billing_cycle_anchor_configuration")
-        private val billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?,
-        @JsonProperty("coupon_redemption_code") private val couponRedemptionCode: String?,
-        @JsonProperty("credits_overage_rate") private val creditsOverageRate: Double?,
-        @JsonProperty("customer_id") private val customerId: String?,
-        @JsonProperty("default_invoice_memo") private val defaultInvoiceMemo: String?,
-        @JsonProperty("end_date") private val endDate: OffsetDateTime?,
-        @JsonProperty("external_customer_id") private val externalCustomerId: String?,
-        @JsonProperty("external_marketplace") private val externalMarketplace: ExternalMarketplace?,
+        @ExcludeMissing
+        private val billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("coupon_redemption_code")
+        @ExcludeMissing
+        private val couponRedemptionCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("credits_overage_rate")
+        @ExcludeMissing
+        private val creditsOverageRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("customer_id")
+        @ExcludeMissing
+        private val customerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("default_invoice_memo")
+        @ExcludeMissing
+        private val defaultInvoiceMemo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("external_customer_id")
+        @ExcludeMissing
+        private val externalCustomerId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_marketplace")
+        @ExcludeMissing
+        private val externalMarketplace: JsonField<ExternalMarketplace> = JsonMissing.of(),
         @JsonProperty("external_marketplace_reporting_id")
-        private val externalMarketplaceReportingId: String?,
-        @JsonProperty("external_plan_id") private val externalPlanId: String?,
-        @JsonProperty("filter") private val filter: String?,
-        @JsonProperty("initial_phase_order") private val initialPhaseOrder: Long?,
-        @JsonProperty("invoicing_threshold") private val invoicingThreshold: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("net_terms") private val netTerms: Long?,
-        @JsonProperty("per_credit_overage_amount") private val perCreditOverageAmount: Double?,
-        @JsonProperty("plan_id") private val planId: String?,
-        @JsonProperty("plan_version_number") private val planVersionNumber: Long?,
-        @JsonProperty("price_overrides") private val priceOverrides: List<JsonValue>?,
-        @JsonProperty("remove_adjustments") private val removeAdjustments: List<RemoveAdjustment>?,
-        @JsonProperty("remove_prices") private val removePrices: List<RemovePrice>?,
+        @ExcludeMissing
+        private val externalMarketplaceReportingId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        private val externalPlanId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("filter")
+        @ExcludeMissing
+        private val filter: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("initial_phase_order")
+        @ExcludeMissing
+        private val initialPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("invoicing_threshold")
+        @ExcludeMissing
+        private val invoicingThreshold: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("per_credit_overage_amount")
+        @ExcludeMissing
+        private val perCreditOverageAmount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("plan_id")
+        @ExcludeMissing
+        private val planId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("plan_version_number")
+        @ExcludeMissing
+        private val planVersionNumber: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("price_overrides")
+        @ExcludeMissing
+        private val priceOverrides: JsonField<List<JsonValue>> = JsonMissing.of(),
+        @JsonProperty("remove_adjustments")
+        @ExcludeMissing
+        private val removeAdjustments: JsonField<List<RemoveAdjustment>> = JsonMissing.of(),
+        @JsonProperty("remove_prices")
+        @ExcludeMissing
+        private val removePrices: JsonField<List<RemovePrice>> = JsonMissing.of(),
         @JsonProperty("replace_adjustments")
-        private val replaceAdjustments: List<ReplaceAdjustment>?,
-        @JsonProperty("replace_prices") private val replacePrices: List<ReplacePrice>?,
-        @JsonProperty("start_date") private val startDate: OffsetDateTime?,
-        @JsonProperty("trial_duration_days") private val trialDurationDays: Long?,
+        @ExcludeMissing
+        private val replaceAdjustments: JsonField<List<ReplaceAdjustment>> = JsonMissing.of(),
+        @JsonProperty("replace_prices")
+        @ExcludeMissing
+        private val replacePrices: JsonField<List<ReplacePrice>> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("trial_duration_days")
+        @ExcludeMissing
+        private val trialDurationDays: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * Additional adjustments to be added to the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun addAdjustments(): Optional<List<AddAdjustment>> =
+            Optional.ofNullable(addAdjustments.getNullable("add_adjustments"))
+
+        /**
+         * Additional prices to be added to the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun addPrices(): Optional<List<AddPrice>> =
+            Optional.ofNullable(addPrices.getNullable("add_prices"))
+
+        fun alignBillingWithSubscriptionStartDate(): Optional<Boolean> =
+            Optional.ofNullable(
+                alignBillingWithSubscriptionStartDate.getNullable(
+                    "align_billing_with_subscription_start_date"
+                )
+            )
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. If not specified, this defaults to the
+         * behavior configured for this customer.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        fun awsRegion(): Optional<String> = Optional.ofNullable(awsRegion.getNullable("aws_region"))
+
+        fun billingCycleAnchorConfiguration(): Optional<BillingCycleAnchorConfiguration> =
+            Optional.ofNullable(
+                billingCycleAnchorConfiguration.getNullable("billing_cycle_anchor_configuration")
+            )
+
+        /**
+         * Redemption code to be used for this subscription. If the coupon cannot be found by its
+         * redemption code, or cannot be redeemed, an error response will be returned and the
+         * subscription creation or plan change will not be scheduled.
+         */
+        fun couponRedemptionCode(): Optional<String> =
+            Optional.ofNullable(couponRedemptionCode.getNullable("coupon_redemption_code"))
+
+        fun creditsOverageRate(): Optional<Double> =
+            Optional.ofNullable(creditsOverageRate.getNullable("credits_overage_rate"))
+
+        fun customerId(): Optional<String> =
+            Optional.ofNullable(customerId.getNullable("customer_id"))
+
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(): Optional<String> =
+            Optional.ofNullable(defaultInvoiceMemo.getNullable("default_invoice_memo"))
+
+        fun endDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(endDate.getNullable("end_date"))
+
+        fun externalCustomerId(): Optional<String> =
+            Optional.ofNullable(externalCustomerId.getNullable("external_customer_id"))
+
+        fun externalMarketplace(): Optional<ExternalMarketplace> =
+            Optional.ofNullable(externalMarketplace.getNullable("external_marketplace"))
+
+        fun externalMarketplaceReportingId(): Optional<String> =
+            Optional.ofNullable(
+                externalMarketplaceReportingId.getNullable("external_marketplace_reporting_id")
+            )
+
+        /**
+         * The external_plan_id of the plan that the given subscription should be switched to. Note
+         * that either this property or `plan_id` must be specified.
+         */
+        fun externalPlanId(): Optional<String> =
+            Optional.ofNullable(externalPlanId.getNullable("external_plan_id"))
+
+        /**
+         * An additional filter to apply to usage queries. This filter must be expressed as a
+         * boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+         * null, usage queries will not include any additional filter.
+         */
+        fun filter(): Optional<String> = Optional.ofNullable(filter.getNullable("filter"))
+
+        /** The phase of the plan to start with */
+        fun initialPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(initialPhaseOrder.getNullable("initial_phase_order"))
+
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(): Optional<String> =
+            Optional.ofNullable(invoicingThreshold.getNullable("invoicing_threshold"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+         * provided, this defaults to the value specified in the plan.
+         */
+        fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms.getNullable("net_terms"))
+
+        fun perCreditOverageAmount(): Optional<Double> =
+            Optional.ofNullable(perCreditOverageAmount.getNullable("per_credit_overage_amount"))
+
+        /**
+         * The plan that the given subscription should be switched to. Note that either this
+         * property or `external_plan_id` must be specified.
+         */
+        fun planId(): Optional<String> = Optional.ofNullable(planId.getNullable("plan_id"))
+
+        /**
+         * Specifies which version of the plan to subscribe to. If null, the default version will be
+         * used.
+         */
+        fun planVersionNumber(): Optional<Long> =
+            Optional.ofNullable(planVersionNumber.getNullable("plan_version_number"))
+
+        /** Optionally provide a list of overrides for prices on the plan */
+        fun priceOverrides(): Optional<List<JsonValue>> =
+            Optional.ofNullable(priceOverrides.getNullable("price_overrides"))
+
+        /**
+         * Plan adjustments to be removed from the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun removeAdjustments(): Optional<List<RemoveAdjustment>> =
+            Optional.ofNullable(removeAdjustments.getNullable("remove_adjustments"))
+
+        /**
+         * Plan prices to be removed from the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun removePrices(): Optional<List<RemovePrice>> =
+            Optional.ofNullable(removePrices.getNullable("remove_prices"))
+
+        /**
+         * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+         * available for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replaceAdjustments(): Optional<List<ReplaceAdjustment>> =
+            Optional.ofNullable(replaceAdjustments.getNullable("replace_adjustments"))
+
+        /**
+         * Plan prices to be replaced with additional prices on the subscription. (Only available
+         * for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replacePrices(): Optional<List<ReplacePrice>> =
+            Optional.ofNullable(replacePrices.getNullable("replace_prices"))
+
+        fun startDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
+        /**
+         * The duration of the trial period in days. If not provided, this defaults to the value
+         * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+         */
+        fun trialDurationDays(): Optional<Long> =
+            Optional.ofNullable(trialDurationDays.getNullable("trial_duration_days"))
+
         /**
          * Additional adjustments to be added to the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
          */
         @JsonProperty("add_adjustments")
-        fun addAdjustments(): Optional<List<AddAdjustment>> = Optional.ofNullable(addAdjustments)
+        @ExcludeMissing
+        fun _addAdjustments(): JsonField<List<AddAdjustment>> = addAdjustments
 
         /**
          * Additional prices to be added to the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
          */
         @JsonProperty("add_prices")
-        fun addPrices(): Optional<List<AddPrice>> = Optional.ofNullable(addPrices)
+        @ExcludeMissing
+        fun _addPrices(): JsonField<List<AddPrice>> = addPrices
 
         @JsonProperty("align_billing_with_subscription_start_date")
-        fun alignBillingWithSubscriptionStartDate(): Optional<Boolean> =
-            Optional.ofNullable(alignBillingWithSubscriptionStartDate)
+        @ExcludeMissing
+        fun _alignBillingWithSubscriptionStartDate(): JsonField<Boolean> =
+            alignBillingWithSubscriptionStartDate
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -254,14 +854,15 @@ constructor(
          * behavior configured for this customer.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
-        @JsonProperty("aws_region")
-        fun awsRegion(): Optional<String> = Optional.ofNullable(awsRegion)
+        @JsonProperty("aws_region") @ExcludeMissing fun _awsRegion(): JsonField<String> = awsRegion
 
         @JsonProperty("billing_cycle_anchor_configuration")
-        fun billingCycleAnchorConfiguration(): Optional<BillingCycleAnchorConfiguration> =
-            Optional.ofNullable(billingCycleAnchorConfiguration)
+        @ExcludeMissing
+        fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+            billingCycleAnchorConfiguration
 
         /**
          * Redemption code to be used for this subscription. If the coupon cannot be found by its
@@ -269,41 +870,48 @@ constructor(
          * subscription creation or plan change will not be scheduled.
          */
         @JsonProperty("coupon_redemption_code")
-        fun couponRedemptionCode(): Optional<String> = Optional.ofNullable(couponRedemptionCode)
+        @ExcludeMissing
+        fun _couponRedemptionCode(): JsonField<String> = couponRedemptionCode
 
         @JsonProperty("credits_overage_rate")
-        fun creditsOverageRate(): Optional<Double> = Optional.ofNullable(creditsOverageRate)
+        @ExcludeMissing
+        fun _creditsOverageRate(): JsonField<Double> = creditsOverageRate
 
         @JsonProperty("customer_id")
-        fun customerId(): Optional<String> = Optional.ofNullable(customerId)
+        @ExcludeMissing
+        fun _customerId(): JsonField<String> = customerId
 
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
         @JsonProperty("default_invoice_memo")
-        fun defaultInvoiceMemo(): Optional<String> = Optional.ofNullable(defaultInvoiceMemo)
+        @ExcludeMissing
+        fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
         @JsonProperty("end_date")
-        fun endDate(): Optional<OffsetDateTime> = Optional.ofNullable(endDate)
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonProperty("external_customer_id")
-        fun externalCustomerId(): Optional<String> = Optional.ofNullable(externalCustomerId)
+        @ExcludeMissing
+        fun _externalCustomerId(): JsonField<String> = externalCustomerId
 
         @JsonProperty("external_marketplace")
-        fun externalMarketplace(): Optional<ExternalMarketplace> =
-            Optional.ofNullable(externalMarketplace)
+        @ExcludeMissing
+        fun _externalMarketplace(): JsonField<ExternalMarketplace> = externalMarketplace
 
         @JsonProperty("external_marketplace_reporting_id")
-        fun externalMarketplaceReportingId(): Optional<String> =
-            Optional.ofNullable(externalMarketplaceReportingId)
+        @ExcludeMissing
+        fun _externalMarketplaceReportingId(): JsonField<String> = externalMarketplaceReportingId
 
         /**
          * The external_plan_id of the plan that the given subscription should be switched to. Note
          * that either this property or `plan_id` must be specified.
          */
         @JsonProperty("external_plan_id")
-        fun externalPlanId(): Optional<String> = Optional.ofNullable(externalPlanId)
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
         /**
          * An additional filter to apply to usage queries. This filter must be expressed as a
@@ -311,11 +919,12 @@ constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
          * null, usage queries will not include any additional filter.
          */
-        @JsonProperty("filter") fun filter(): Optional<String> = Optional.ofNullable(filter)
+        @JsonProperty("filter") @ExcludeMissing fun _filter(): JsonField<String> = filter
 
         /** The phase of the plan to start with */
         @JsonProperty("initial_phase_order")
-        fun initialPhaseOrder(): Optional<Long> = Optional.ofNullable(initialPhaseOrder)
+        @ExcludeMissing
+        fun _initialPhaseOrder(): JsonField<Long> = initialPhaseOrder
 
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
@@ -323,86 +932,132 @@ constructor(
          * billing period.
          */
         @JsonProperty("invoicing_threshold")
-        fun invoicingThreshold(): Optional<String> = Optional.ofNullable(invoicingThreshold)
+        @ExcludeMissing
+        fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
          * provided, this defaults to the value specified in the plan.
          */
-        @JsonProperty("net_terms") fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms)
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         @JsonProperty("per_credit_overage_amount")
-        fun perCreditOverageAmount(): Optional<Double> = Optional.ofNullable(perCreditOverageAmount)
+        @ExcludeMissing
+        fun _perCreditOverageAmount(): JsonField<Double> = perCreditOverageAmount
 
         /**
          * The plan that the given subscription should be switched to. Note that either this
          * property or `external_plan_id` must be specified.
          */
-        @JsonProperty("plan_id") fun planId(): Optional<String> = Optional.ofNullable(planId)
+        @JsonProperty("plan_id") @ExcludeMissing fun _planId(): JsonField<String> = planId
 
         /**
          * Specifies which version of the plan to subscribe to. If null, the default version will be
          * used.
          */
         @JsonProperty("plan_version_number")
-        fun planVersionNumber(): Optional<Long> = Optional.ofNullable(planVersionNumber)
+        @ExcludeMissing
+        fun _planVersionNumber(): JsonField<Long> = planVersionNumber
 
         /** Optionally provide a list of overrides for prices on the plan */
         @JsonProperty("price_overrides")
-        fun priceOverrides(): Optional<List<JsonValue>> = Optional.ofNullable(priceOverrides)
+        @ExcludeMissing
+        fun _priceOverrides(): JsonField<List<JsonValue>> = priceOverrides
 
         /**
          * Plan adjustments to be removed from the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
          */
         @JsonProperty("remove_adjustments")
-        fun removeAdjustments(): Optional<List<RemoveAdjustment>> =
-            Optional.ofNullable(removeAdjustments)
+        @ExcludeMissing
+        fun _removeAdjustments(): JsonField<List<RemoveAdjustment>> = removeAdjustments
 
         /**
          * Plan prices to be removed from the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
          */
         @JsonProperty("remove_prices")
-        fun removePrices(): Optional<List<RemovePrice>> = Optional.ofNullable(removePrices)
+        @ExcludeMissing
+        fun _removePrices(): JsonField<List<RemovePrice>> = removePrices
 
         /**
          * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
          * available for accounts that have migrated off of legacy subscription overrides)
          */
         @JsonProperty("replace_adjustments")
-        fun replaceAdjustments(): Optional<List<ReplaceAdjustment>> =
-            Optional.ofNullable(replaceAdjustments)
+        @ExcludeMissing
+        fun _replaceAdjustments(): JsonField<List<ReplaceAdjustment>> = replaceAdjustments
 
         /**
          * Plan prices to be replaced with additional prices on the subscription. (Only available
          * for accounts that have migrated off of legacy subscription overrides)
          */
         @JsonProperty("replace_prices")
-        fun replacePrices(): Optional<List<ReplacePrice>> = Optional.ofNullable(replacePrices)
+        @ExcludeMissing
+        fun _replacePrices(): JsonField<List<ReplacePrice>> = replacePrices
 
         @JsonProperty("start_date")
-        fun startDate(): Optional<OffsetDateTime> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         /**
          * The duration of the trial period in days. If not provided, this defaults to the value
          * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
          */
         @JsonProperty("trial_duration_days")
-        fun trialDurationDays(): Optional<Long> = Optional.ofNullable(trialDurationDays)
+        @ExcludeMissing
+        fun _trialDurationDays(): JsonField<Long> = trialDurationDays
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionCreateBody = apply {
+            if (!validated) {
+                addAdjustments().map { it.forEach { it.validate() } }
+                addPrices().map { it.forEach { it.validate() } }
+                alignBillingWithSubscriptionStartDate()
+                autoCollection()
+                awsRegion()
+                billingCycleAnchorConfiguration().map { it.validate() }
+                couponRedemptionCode()
+                creditsOverageRate()
+                customerId()
+                defaultInvoiceMemo()
+                endDate()
+                externalCustomerId()
+                externalMarketplace()
+                externalMarketplaceReportingId()
+                externalPlanId()
+                filter()
+                initialPhaseOrder()
+                invoicingThreshold()
+                metadata().map { it.validate() }
+                netTerms()
+                perCreditOverageAmount()
+                planId()
+                planVersionNumber()
+                priceOverrides()
+                removeAdjustments().map { it.forEach { it.validate() } }
+                removePrices().map { it.forEach { it.validate() } }
+                replaceAdjustments().map { it.forEach { it.validate() } }
+                replacePrices().map { it.forEach { it.validate() } }
+                startDate()
+                trialDurationDays()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -412,42 +1067,44 @@ constructor(
 
         class Builder {
 
-            private var addAdjustments: MutableList<AddAdjustment>? = null
-            private var addPrices: MutableList<AddPrice>? = null
-            private var alignBillingWithSubscriptionStartDate: Boolean? = null
-            private var autoCollection: Boolean? = null
-            private var awsRegion: String? = null
-            private var billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration? = null
-            private var couponRedemptionCode: String? = null
-            private var creditsOverageRate: Double? = null
-            private var customerId: String? = null
-            private var defaultInvoiceMemo: String? = null
-            private var endDate: OffsetDateTime? = null
-            private var externalCustomerId: String? = null
-            private var externalMarketplace: ExternalMarketplace? = null
-            private var externalMarketplaceReportingId: String? = null
-            private var externalPlanId: String? = null
-            private var filter: String? = null
-            private var initialPhaseOrder: Long? = null
-            private var invoicingThreshold: String? = null
-            private var metadata: Metadata? = null
-            private var netTerms: Long? = null
-            private var perCreditOverageAmount: Double? = null
-            private var planId: String? = null
-            private var planVersionNumber: Long? = null
-            private var priceOverrides: MutableList<JsonValue>? = null
-            private var removeAdjustments: MutableList<RemoveAdjustment>? = null
-            private var removePrices: MutableList<RemovePrice>? = null
-            private var replaceAdjustments: MutableList<ReplaceAdjustment>? = null
-            private var replacePrices: MutableList<ReplacePrice>? = null
-            private var startDate: OffsetDateTime? = null
-            private var trialDurationDays: Long? = null
+            private var addAdjustments: JsonField<MutableList<AddAdjustment>>? = null
+            private var addPrices: JsonField<MutableList<AddPrice>>? = null
+            private var alignBillingWithSubscriptionStartDate: JsonField<Boolean> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var awsRegion: JsonField<String> = JsonMissing.of()
+            private var billingCycleAnchorConfiguration:
+                JsonField<BillingCycleAnchorConfiguration> =
+                JsonMissing.of()
+            private var couponRedemptionCode: JsonField<String> = JsonMissing.of()
+            private var creditsOverageRate: JsonField<Double> = JsonMissing.of()
+            private var customerId: JsonField<String> = JsonMissing.of()
+            private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var externalCustomerId: JsonField<String> = JsonMissing.of()
+            private var externalMarketplace: JsonField<ExternalMarketplace> = JsonMissing.of()
+            private var externalMarketplaceReportingId: JsonField<String> = JsonMissing.of()
+            private var externalPlanId: JsonField<String> = JsonMissing.of()
+            private var filter: JsonField<String> = JsonMissing.of()
+            private var initialPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var invoicingThreshold: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var perCreditOverageAmount: JsonField<Double> = JsonMissing.of()
+            private var planId: JsonField<String> = JsonMissing.of()
+            private var planVersionNumber: JsonField<Long> = JsonMissing.of()
+            private var priceOverrides: JsonField<MutableList<JsonValue>>? = null
+            private var removeAdjustments: JsonField<MutableList<RemoveAdjustment>>? = null
+            private var removePrices: JsonField<MutableList<RemovePrice>>? = null
+            private var replaceAdjustments: JsonField<MutableList<ReplaceAdjustment>>? = null
+            private var replacePrices: JsonField<MutableList<ReplacePrice>>? = null
+            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var trialDurationDays: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(subscriptionCreateBody: SubscriptionCreateBody) = apply {
-                addAdjustments = subscriptionCreateBody.addAdjustments?.toMutableList()
-                addPrices = subscriptionCreateBody.addPrices?.toMutableList()
+                addAdjustments = subscriptionCreateBody.addAdjustments.map { it.toMutableList() }
+                addPrices = subscriptionCreateBody.addPrices.map { it.toMutableList() }
                 alignBillingWithSubscriptionStartDate =
                     subscriptionCreateBody.alignBillingWithSubscriptionStartDate
                 autoCollection = subscriptionCreateBody.autoCollection
@@ -472,11 +1129,13 @@ constructor(
                 perCreditOverageAmount = subscriptionCreateBody.perCreditOverageAmount
                 planId = subscriptionCreateBody.planId
                 planVersionNumber = subscriptionCreateBody.planVersionNumber
-                priceOverrides = subscriptionCreateBody.priceOverrides?.toMutableList()
-                removeAdjustments = subscriptionCreateBody.removeAdjustments?.toMutableList()
-                removePrices = subscriptionCreateBody.removePrices?.toMutableList()
-                replaceAdjustments = subscriptionCreateBody.replaceAdjustments?.toMutableList()
-                replacePrices = subscriptionCreateBody.replacePrices?.toMutableList()
+                priceOverrides = subscriptionCreateBody.priceOverrides.map { it.toMutableList() }
+                removeAdjustments =
+                    subscriptionCreateBody.removeAdjustments.map { it.toMutableList() }
+                removePrices = subscriptionCreateBody.removePrices.map { it.toMutableList() }
+                replaceAdjustments =
+                    subscriptionCreateBody.replaceAdjustments.map { it.toMutableList() }
+                replacePrices = subscriptionCreateBody.replacePrices.map { it.toMutableList() }
                 startDate = subscriptionCreateBody.startDate
                 trialDurationDays = subscriptionCreateBody.trialDurationDays
                 additionalProperties = subscriptionCreateBody.additionalProperties.toMutableMap()
@@ -486,9 +1145,8 @@ constructor(
              * Additional adjustments to be added to the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
-            fun addAdjustments(addAdjustments: List<AddAdjustment>?) = apply {
-                this.addAdjustments = addAdjustments?.toMutableList()
-            }
+            fun addAdjustments(addAdjustments: List<AddAdjustment>?) =
+                addAdjustments(JsonField.ofNullable(addAdjustments))
 
             /**
              * Additional adjustments to be added to the subscription. (Only available for accounts
@@ -497,21 +1155,36 @@ constructor(
             fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
                 addAdjustments(addAdjustments.orElse(null))
 
+            /**
+             * Additional adjustments to be added to the subscription. (Only available for accounts
+             * that have migrated off of legacy subscription overrides)
+             */
+            fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+                this.addAdjustments = addAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Additional adjustments to be added to the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
             fun addAddAdjustment(addAdjustment: AddAdjustment) = apply {
-                addAdjustments = (addAdjustments ?: mutableListOf()).apply { add(addAdjustment) }
+                addAdjustments =
+                    (addAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(addAdjustment)
+                    }
             }
 
             /**
              * Additional prices to be added to the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
-            fun addPrices(addPrices: List<AddPrice>?) = apply {
-                this.addPrices = addPrices?.toMutableList()
-            }
+            fun addPrices(addPrices: List<AddPrice>?) = addPrices(JsonField.ofNullable(addPrices))
 
             /**
              * Additional prices to be added to the subscription. (Only available for accounts that
@@ -523,39 +1196,47 @@ constructor(
              * Additional prices to be added to the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
-            fun addAddPrice(addPrice: AddPrice) = apply {
-                addPrices = (addPrices ?: mutableListOf()).apply { add(addPrice) }
+            fun addPrices(addPrices: JsonField<List<AddPrice>>) = apply {
+                this.addPrices = addPrices.map { it.toMutableList() }
             }
 
-            fun alignBillingWithSubscriptionStartDate(
-                alignBillingWithSubscriptionStartDate: Boolean?
-            ) = apply {
-                this.alignBillingWithSubscriptionStartDate = alignBillingWithSubscriptionStartDate
+            /**
+             * Additional prices to be added to the subscription. (Only available for accounts that
+             * have migrated off of legacy subscription overrides)
+             */
+            fun addAddPrice(addPrice: AddPrice) = apply {
+                addPrices =
+                    (addPrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(addPrice)
+                    }
             }
 
             fun alignBillingWithSubscriptionStartDate(
                 alignBillingWithSubscriptionStartDate: Boolean
             ) =
                 alignBillingWithSubscriptionStartDate(
-                    alignBillingWithSubscriptionStartDate as Boolean?
+                    JsonField.of(alignBillingWithSubscriptionStartDate)
                 )
 
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun alignBillingWithSubscriptionStartDate(
-                alignBillingWithSubscriptionStartDate: Optional<Boolean>
-            ) =
-                alignBillingWithSubscriptionStartDate(
-                    alignBillingWithSubscriptionStartDate.orElse(null) as Boolean?
-                )
+                alignBillingWithSubscriptionStartDate: JsonField<Boolean>
+            ) = apply {
+                this.alignBillingWithSubscriptionStartDate = alignBillingWithSubscriptionStartDate
+            }
 
             /**
              * Determines whether issued invoices for this subscription will automatically be
              * charged with the saved payment method on the due date. If not specified, this
              * defaults to the behavior configured for this customer.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Determines whether issued invoices for this subscription will automatically be
@@ -573,26 +1254,43 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
-            fun awsRegion(awsRegion: String?) = apply { this.awsRegion = awsRegion }
+            /**
+             * Determines whether issued invoices for this subscription will automatically be
+             * charged with the saved payment method on the due date. If not specified, this
+             * defaults to the behavior configured for this customer.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
+            }
+
+            fun awsRegion(awsRegion: String?) = awsRegion(JsonField.ofNullable(awsRegion))
 
             fun awsRegion(awsRegion: Optional<String>) = awsRegion(awsRegion.orElse(null))
 
+            fun awsRegion(awsRegion: JsonField<String>) = apply { this.awsRegion = awsRegion }
+
             fun billingCycleAnchorConfiguration(
                 billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?
-            ) = apply { this.billingCycleAnchorConfiguration = billingCycleAnchorConfiguration }
+            ) =
+                billingCycleAnchorConfiguration(
+                    JsonField.ofNullable(billingCycleAnchorConfiguration)
+                )
 
             fun billingCycleAnchorConfiguration(
                 billingCycleAnchorConfiguration: Optional<BillingCycleAnchorConfiguration>
             ) = billingCycleAnchorConfiguration(billingCycleAnchorConfiguration.orElse(null))
 
+            fun billingCycleAnchorConfiguration(
+                billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>
+            ) = apply { this.billingCycleAnchorConfiguration = billingCycleAnchorConfiguration }
+
             /**
              * Redemption code to be used for this subscription. If the coupon cannot be found by
              * its redemption code, or cannot be redeemed, an error response will be returned and
              * the subscription creation or plan change will not be scheduled.
              */
-            fun couponRedemptionCode(couponRedemptionCode: String?) = apply {
-                this.couponRedemptionCode = couponRedemptionCode
-            }
+            fun couponRedemptionCode(couponRedemptionCode: String?) =
+                couponRedemptionCode(JsonField.ofNullable(couponRedemptionCode))
 
             /**
              * Redemption code to be used for this subscription. If the coupon cannot be found by
@@ -602,10 +1300,18 @@ constructor(
             fun couponRedemptionCode(couponRedemptionCode: Optional<String>) =
                 couponRedemptionCode(couponRedemptionCode.orElse(null))
 
-            fun creditsOverageRate(creditsOverageRate: Double?) = apply {
-                this.creditsOverageRate = creditsOverageRate
+            /**
+             * Redemption code to be used for this subscription. If the coupon cannot be found by
+             * its redemption code, or cannot be redeemed, an error response will be returned and
+             * the subscription creation or plan change will not be scheduled.
+             */
+            fun couponRedemptionCode(couponRedemptionCode: JsonField<String>) = apply {
+                this.couponRedemptionCode = couponRedemptionCode
             }
 
+            fun creditsOverageRate(creditsOverageRate: Double?) =
+                creditsOverageRate(JsonField.ofNullable(creditsOverageRate))
+
             fun creditsOverageRate(creditsOverageRate: Double) =
                 creditsOverageRate(creditsOverageRate as Double?)
 
@@ -613,17 +1319,22 @@ constructor(
             fun creditsOverageRate(creditsOverageRate: Optional<Double>) =
                 creditsOverageRate(creditsOverageRate.orElse(null) as Double?)
 
-            fun customerId(customerId: String?) = apply { this.customerId = customerId }
+            fun creditsOverageRate(creditsOverageRate: JsonField<Double>) = apply {
+                this.creditsOverageRate = creditsOverageRate
+            }
+
+            fun customerId(customerId: String?) = customerId(JsonField.ofNullable(customerId))
 
             fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+            fun customerId(customerId: JsonField<String>) = apply { this.customerId = customerId }
+
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
              * provided, it is determined by the plan configuration.
              */
-            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) = apply {
-                this.defaultInvoiceMemo = defaultInvoiceMemo
-            }
+            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+                defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
 
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
@@ -632,38 +1343,57 @@ constructor(
             fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
                 defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
-            fun endDate(endDate: OffsetDateTime?) = apply { this.endDate = endDate }
+            /**
+             * Determines the default memo on this subscription's invoices. Note that if this is not
+             * provided, it is determined by the plan configuration.
+             */
+            fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+                this.defaultInvoiceMemo = defaultInvoiceMemo
+            }
+
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
 
             fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
-            fun externalCustomerId(externalCustomerId: String?) = apply {
-                this.externalCustomerId = externalCustomerId
-            }
+            fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
+
+            fun externalCustomerId(externalCustomerId: String?) =
+                externalCustomerId(JsonField.ofNullable(externalCustomerId))
 
             fun externalCustomerId(externalCustomerId: Optional<String>) =
                 externalCustomerId(externalCustomerId.orElse(null))
 
-            fun externalMarketplace(externalMarketplace: ExternalMarketplace?) = apply {
-                this.externalMarketplace = externalMarketplace
+            fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+                this.externalCustomerId = externalCustomerId
             }
 
+            fun externalMarketplace(externalMarketplace: ExternalMarketplace?) =
+                externalMarketplace(JsonField.ofNullable(externalMarketplace))
+
             fun externalMarketplace(externalMarketplace: Optional<ExternalMarketplace>) =
                 externalMarketplace(externalMarketplace.orElse(null))
 
-            fun externalMarketplaceReportingId(externalMarketplaceReportingId: String?) = apply {
-                this.externalMarketplaceReportingId = externalMarketplaceReportingId
+            fun externalMarketplace(externalMarketplace: JsonField<ExternalMarketplace>) = apply {
+                this.externalMarketplace = externalMarketplace
             }
 
+            fun externalMarketplaceReportingId(externalMarketplaceReportingId: String?) =
+                externalMarketplaceReportingId(JsonField.ofNullable(externalMarketplaceReportingId))
+
             fun externalMarketplaceReportingId(externalMarketplaceReportingId: Optional<String>) =
                 externalMarketplaceReportingId(externalMarketplaceReportingId.orElse(null))
 
+            fun externalMarketplaceReportingId(externalMarketplaceReportingId: JsonField<String>) =
+                apply {
+                    this.externalMarketplaceReportingId = externalMarketplaceReportingId
+                }
+
             /**
              * The external_plan_id of the plan that the given subscription should be switched to.
              * Note that either this property or `plan_id` must be specified.
              */
-            fun externalPlanId(externalPlanId: String?) = apply {
-                this.externalPlanId = externalPlanId
-            }
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
 
             /**
              * The external_plan_id of the plan that the given subscription should be switched to.
@@ -672,13 +1402,21 @@ constructor(
             fun externalPlanId(externalPlanId: Optional<String>) =
                 externalPlanId(externalPlanId.orElse(null))
 
+            /**
+             * The external_plan_id of the plan that the given subscription should be switched to.
+             * Note that either this property or `plan_id` must be specified.
+             */
+            fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+                this.externalPlanId = externalPlanId
+            }
+
             /**
              * An additional filter to apply to usage queries. This filter must be expressed as a
              * boolean
              * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
              * null, usage queries will not include any additional filter.
              */
-            fun filter(filter: String?) = apply { this.filter = filter }
+            fun filter(filter: String?) = filter(JsonField.ofNullable(filter))
 
             /**
              * An additional filter to apply to usage queries. This filter must be expressed as a
@@ -688,10 +1426,17 @@ constructor(
              */
             fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+            /**
+             * An additional filter to apply to usage queries. This filter must be expressed as a
+             * boolean
+             * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+             * null, usage queries will not include any additional filter.
+             */
+            fun filter(filter: JsonField<String>) = apply { this.filter = filter }
+
             /** The phase of the plan to start with */
-            fun initialPhaseOrder(initialPhaseOrder: Long?) = apply {
-                this.initialPhaseOrder = initialPhaseOrder
-            }
+            fun initialPhaseOrder(initialPhaseOrder: Long?) =
+                initialPhaseOrder(JsonField.ofNullable(initialPhaseOrder))
 
             /** The phase of the plan to start with */
             fun initialPhaseOrder(initialPhaseOrder: Long) =
@@ -702,14 +1447,18 @@ constructor(
             fun initialPhaseOrder(initialPhaseOrder: Optional<Long>) =
                 initialPhaseOrder(initialPhaseOrder.orElse(null) as Long?)
 
+            /** The phase of the plan to start with */
+            fun initialPhaseOrder(initialPhaseOrder: JsonField<Long>) = apply {
+                this.initialPhaseOrder = initialPhaseOrder
+            }
+
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
              * issued for the subscription. If not specified, invoices will only be issued at the
              * end of the billing period.
              */
-            fun invoicingThreshold(invoicingThreshold: String?) = apply {
-                this.invoicingThreshold = invoicingThreshold
-            }
+            fun invoicingThreshold(invoicingThreshold: String?) =
+                invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
 
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
@@ -719,12 +1468,21 @@ constructor(
             fun invoicingThreshold(invoicingThreshold: Optional<String>) =
                 invoicingThreshold(invoicingThreshold.orElse(null))
 
+            /**
+             * When this subscription's accrued usage reaches this threshold, an invoice will be
+             * issued for the subscription. If not specified, invoices will only be issued at the
+             * end of the billing period.
+             */
+            fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+                this.invoicingThreshold = invoicingThreshold
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -733,12 +1491,19 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0. If not
              * provided, this defaults to the value specified in the plan.
              */
-            fun netTerms(netTerms: Long?) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long?) = netTerms(JsonField.ofNullable(netTerms))
 
             /**
              * The net terms determines the difference between the invoice date and the issue date
@@ -755,9 +1520,15 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
-            fun perCreditOverageAmount(perCreditOverageAmount: Double?) = apply {
-                this.perCreditOverageAmount = perCreditOverageAmount
-            }
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+             * provided, this defaults to the value specified in the plan.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
+
+            fun perCreditOverageAmount(perCreditOverageAmount: Double?) =
+                perCreditOverageAmount(JsonField.ofNullable(perCreditOverageAmount))
 
             fun perCreditOverageAmount(perCreditOverageAmount: Double) =
                 perCreditOverageAmount(perCreditOverageAmount as Double?)
@@ -766,11 +1537,15 @@ constructor(
             fun perCreditOverageAmount(perCreditOverageAmount: Optional<Double>) =
                 perCreditOverageAmount(perCreditOverageAmount.orElse(null) as Double?)
 
+            fun perCreditOverageAmount(perCreditOverageAmount: JsonField<Double>) = apply {
+                this.perCreditOverageAmount = perCreditOverageAmount
+            }
+
             /**
              * The plan that the given subscription should be switched to. Note that either this
              * property or `external_plan_id` must be specified.
              */
-            fun planId(planId: String?) = apply { this.planId = planId }
+            fun planId(planId: String?) = planId(JsonField.ofNullable(planId))
 
             /**
              * The plan that the given subscription should be switched to. Note that either this
@@ -778,13 +1553,18 @@ constructor(
              */
             fun planId(planId: Optional<String>) = planId(planId.orElse(null))
 
+            /**
+             * The plan that the given subscription should be switched to. Note that either this
+             * property or `external_plan_id` must be specified.
+             */
+            fun planId(planId: JsonField<String>) = apply { this.planId = planId }
+
             /**
              * Specifies which version of the plan to subscribe to. If null, the default version
              * will be used.
              */
-            fun planVersionNumber(planVersionNumber: Long?) = apply {
-                this.planVersionNumber = planVersionNumber
-            }
+            fun planVersionNumber(planVersionNumber: Long?) =
+                planVersionNumber(JsonField.ofNullable(planVersionNumber))
 
             /**
              * Specifies which version of the plan to subscribe to. If null, the default version
@@ -801,27 +1581,47 @@ constructor(
             fun planVersionNumber(planVersionNumber: Optional<Long>) =
                 planVersionNumber(planVersionNumber.orElse(null) as Long?)
 
-            /** Optionally provide a list of overrides for prices on the plan */
-            fun priceOverrides(priceOverrides: List<JsonValue>?) = apply {
-                this.priceOverrides = priceOverrides?.toMutableList()
+            /**
+             * Specifies which version of the plan to subscribe to. If null, the default version
+             * will be used.
+             */
+            fun planVersionNumber(planVersionNumber: JsonField<Long>) = apply {
+                this.planVersionNumber = planVersionNumber
             }
 
+            /** Optionally provide a list of overrides for prices on the plan */
+            fun priceOverrides(priceOverrides: List<JsonValue>?) =
+                priceOverrides(JsonField.ofNullable(priceOverrides))
+
             /** Optionally provide a list of overrides for prices on the plan */
             fun priceOverrides(priceOverrides: Optional<List<JsonValue>>) =
                 priceOverrides(priceOverrides.orElse(null))
 
+            /** Optionally provide a list of overrides for prices on the plan */
+            fun priceOverrides(priceOverrides: JsonField<List<JsonValue>>) = apply {
+                this.priceOverrides = priceOverrides.map { it.toMutableList() }
+            }
+
             /** Optionally provide a list of overrides for prices on the plan */
             fun addPriceOverride(priceOverride: JsonValue) = apply {
-                priceOverrides = (priceOverrides ?: mutableListOf()).apply { add(priceOverride) }
+                priceOverrides =
+                    (priceOverrides ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(priceOverride)
+                    }
             }
 
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
-            fun removeAdjustments(removeAdjustments: List<RemoveAdjustment>?) = apply {
-                this.removeAdjustments = removeAdjustments?.toMutableList()
-            }
+            fun removeAdjustments(removeAdjustments: List<RemoveAdjustment>?) =
+                removeAdjustments(JsonField.ofNullable(removeAdjustments))
 
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
@@ -830,22 +1630,37 @@ constructor(
             fun removeAdjustments(removeAdjustments: Optional<List<RemoveAdjustment>>) =
                 removeAdjustments(removeAdjustments.orElse(null))
 
+            /**
+             * Plan adjustments to be removed from the subscription. (Only available for accounts
+             * that have migrated off of legacy subscription overrides)
+             */
+            fun removeAdjustments(removeAdjustments: JsonField<List<RemoveAdjustment>>) = apply {
+                this.removeAdjustments = removeAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
             fun addRemoveAdjustment(removeAdjustment: RemoveAdjustment) = apply {
                 removeAdjustments =
-                    (removeAdjustments ?: mutableListOf()).apply { add(removeAdjustment) }
+                    (removeAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(removeAdjustment)
+                    }
             }
 
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
-            fun removePrices(removePrices: List<RemovePrice>?) = apply {
-                this.removePrices = removePrices?.toMutableList()
-            }
+            fun removePrices(removePrices: List<RemovePrice>?) =
+                removePrices(JsonField.ofNullable(removePrices))
 
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
@@ -854,21 +1669,37 @@ constructor(
             fun removePrices(removePrices: Optional<List<RemovePrice>>) =
                 removePrices(removePrices.orElse(null))
 
+            /**
+             * Plan prices to be removed from the subscription. (Only available for accounts that
+             * have migrated off of legacy subscription overrides)
+             */
+            fun removePrices(removePrices: JsonField<List<RemovePrice>>) = apply {
+                this.removePrices = removePrices.map { it.toMutableList() }
+            }
+
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
             fun addRemovePrice(removePrice: RemovePrice) = apply {
-                removePrices = (removePrices ?: mutableListOf()).apply { add(removePrice) }
+                removePrices =
+                    (removePrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(removePrice)
+                    }
             }
 
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
              * (Only available for accounts that have migrated off of legacy subscription overrides)
              */
-            fun replaceAdjustments(replaceAdjustments: List<ReplaceAdjustment>?) = apply {
-                this.replaceAdjustments = replaceAdjustments?.toMutableList()
-            }
+            fun replaceAdjustments(replaceAdjustments: List<ReplaceAdjustment>?) =
+                replaceAdjustments(JsonField.ofNullable(replaceAdjustments))
 
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
@@ -877,22 +1708,37 @@ constructor(
             fun replaceAdjustments(replaceAdjustments: Optional<List<ReplaceAdjustment>>) =
                 replaceAdjustments(replaceAdjustments.orElse(null))
 
+            /**
+             * Plan adjustments to be replaced with additional adjustments on the subscription.
+             * (Only available for accounts that have migrated off of legacy subscription overrides)
+             */
+            fun replaceAdjustments(replaceAdjustments: JsonField<List<ReplaceAdjustment>>) = apply {
+                this.replaceAdjustments = replaceAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
              * (Only available for accounts that have migrated off of legacy subscription overrides)
              */
             fun addReplaceAdjustment(replaceAdjustment: ReplaceAdjustment) = apply {
                 replaceAdjustments =
-                    (replaceAdjustments ?: mutableListOf()).apply { add(replaceAdjustment) }
+                    (replaceAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(replaceAdjustment)
+                    }
             }
 
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
              * available for accounts that have migrated off of legacy subscription overrides)
              */
-            fun replacePrices(replacePrices: List<ReplacePrice>?) = apply {
-                this.replacePrices = replacePrices?.toMutableList()
-            }
+            fun replacePrices(replacePrices: List<ReplacePrice>?) =
+                replacePrices(JsonField.ofNullable(replacePrices))
 
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
@@ -901,25 +1747,45 @@ constructor(
             fun replacePrices(replacePrices: Optional<List<ReplacePrice>>) =
                 replacePrices(replacePrices.orElse(null))
 
+            /**
+             * Plan prices to be replaced with additional prices on the subscription. (Only
+             * available for accounts that have migrated off of legacy subscription overrides)
+             */
+            fun replacePrices(replacePrices: JsonField<List<ReplacePrice>>) = apply {
+                this.replacePrices = replacePrices.map { it.toMutableList() }
+            }
+
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
              * available for accounts that have migrated off of legacy subscription overrides)
              */
             fun addReplacePrice(replacePrice: ReplacePrice) = apply {
-                replacePrices = (replacePrices ?: mutableListOf()).apply { add(replacePrice) }
+                replacePrices =
+                    (replacePrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(replacePrice)
+                    }
             }
 
-            fun startDate(startDate: OffsetDateTime?) = apply { this.startDate = startDate }
+            fun startDate(startDate: OffsetDateTime?) = startDate(JsonField.ofNullable(startDate))
 
             fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+            fun startDate(startDate: JsonField<OffsetDateTime>) = apply {
+                this.startDate = startDate
+            }
+
             /**
              * The duration of the trial period in days. If not provided, this defaults to the value
              * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
              */
-            fun trialDurationDays(trialDurationDays: Long?) = apply {
-                this.trialDurationDays = trialDurationDays
-            }
+            fun trialDurationDays(trialDurationDays: Long?) =
+                trialDurationDays(JsonField.ofNullable(trialDurationDays))
 
             /**
              * The duration of the trial period in days. If not provided, this defaults to the value
@@ -936,6 +1802,14 @@ constructor(
             fun trialDurationDays(trialDurationDays: Optional<Long>) =
                 trialDurationDays(trialDurationDays.orElse(null) as Long?)
 
+            /**
+             * The duration of the trial period in days. If not provided, this defaults to the value
+             * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+             */
+            fun trialDurationDays(trialDurationDays: JsonField<Long>) = apply {
+                this.trialDurationDays = trialDurationDays
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -957,8 +1831,8 @@ constructor(
 
             fun build(): SubscriptionCreateBody =
                 SubscriptionCreateBody(
-                    addAdjustments?.toImmutable(),
-                    addPrices?.toImmutable(),
+                    (addAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (addPrices ?: JsonMissing.of()).map { it.toImmutable() },
                     alignBillingWithSubscriptionStartDate,
                     autoCollection,
                     awsRegion,
@@ -980,11 +1854,11 @@ constructor(
                     perCreditOverageAmount,
                     planId,
                     planVersionNumber,
-                    priceOverrides?.toImmutable(),
-                    removeAdjustments?.toImmutable(),
-                    removePrices?.toImmutable(),
-                    replaceAdjustments?.toImmutable(),
-                    replacePrices?.toImmutable(),
+                    (priceOverrides ?: JsonMissing.of()).map { it.toImmutable() },
+                    (removeAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (removePrices ?: JsonMissing.of()).map { it.toImmutable() },
+                    (replaceAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (replacePrices ?: JsonMissing.of()).map { it.toImmutable() },
                     startDate,
                     trialDurationDays,
                     additionalProperties.toImmutable(),
@@ -1045,6 +1919,14 @@ constructor(
         fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
             addAdjustments(addAdjustments.orElse(null))
 
+        /**
+         * Additional adjustments to be added to the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+            body.addAdjustments(addAdjustments)
+        }
+
         /**
          * Additional adjustments to be added to the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
@@ -1065,27 +1947,28 @@ constructor(
          */
         fun addPrices(addPrices: Optional<List<AddPrice>>) = addPrices(addPrices.orElse(null))
 
+        /**
+         * Additional prices to be added to the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun addPrices(addPrices: JsonField<List<AddPrice>>) = apply { body.addPrices(addPrices) }
+
         /**
          * Additional prices to be added to the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
          */
         fun addAddPrice(addPrice: AddPrice) = apply { body.addAddPrice(addPrice) }
 
-        fun alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate: Boolean?) =
+        fun alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate: Boolean) =
             apply {
                 body.alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate)
             }
 
-        fun alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate: Boolean) =
-            alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate as Boolean?)
-
-        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
         fun alignBillingWithSubscriptionStartDate(
-            alignBillingWithSubscriptionStartDate: Optional<Boolean>
-        ) =
-            alignBillingWithSubscriptionStartDate(
-                alignBillingWithSubscriptionStartDate.orElse(null) as Boolean?
-            )
+            alignBillingWithSubscriptionStartDate: JsonField<Boolean>
+        ) = apply {
+            body.alignBillingWithSubscriptionStartDate(alignBillingWithSubscriptionStartDate)
+        }
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -1110,10 +1993,21 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. If not specified, this defaults to the
+         * behavior configured for this customer.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         fun awsRegion(awsRegion: String?) = apply { body.awsRegion(awsRegion) }
 
         fun awsRegion(awsRegion: Optional<String>) = awsRegion(awsRegion.orElse(null))
 
+        fun awsRegion(awsRegion: JsonField<String>) = apply { body.awsRegion(awsRegion) }
+
         fun billingCycleAnchorConfiguration(
             billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?
         ) = apply { body.billingCycleAnchorConfiguration(billingCycleAnchorConfiguration) }
@@ -1122,6 +2016,10 @@ constructor(
             billingCycleAnchorConfiguration: Optional<BillingCycleAnchorConfiguration>
         ) = billingCycleAnchorConfiguration(billingCycleAnchorConfiguration.orElse(null))
 
+        fun billingCycleAnchorConfiguration(
+            billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>
+        ) = apply { body.billingCycleAnchorConfiguration(billingCycleAnchorConfiguration) }
+
         /**
          * Redemption code to be used for this subscription. If the coupon cannot be found by its
          * redemption code, or cannot be redeemed, an error response will be returned and the
@@ -1139,6 +2037,15 @@ constructor(
         fun couponRedemptionCode(couponRedemptionCode: Optional<String>) =
             couponRedemptionCode(couponRedemptionCode.orElse(null))
 
+        /**
+         * Redemption code to be used for this subscription. If the coupon cannot be found by its
+         * redemption code, or cannot be redeemed, an error response will be returned and the
+         * subscription creation or plan change will not be scheduled.
+         */
+        fun couponRedemptionCode(couponRedemptionCode: JsonField<String>) = apply {
+            body.couponRedemptionCode(couponRedemptionCode)
+        }
+
         fun creditsOverageRate(creditsOverageRate: Double?) = apply {
             body.creditsOverageRate(creditsOverageRate)
         }
@@ -1150,10 +2057,16 @@ constructor(
         fun creditsOverageRate(creditsOverageRate: Optional<Double>) =
             creditsOverageRate(creditsOverageRate.orElse(null) as Double?)
 
+        fun creditsOverageRate(creditsOverageRate: JsonField<Double>) = apply {
+            body.creditsOverageRate(creditsOverageRate)
+        }
+
         fun customerId(customerId: String?) = apply { body.customerId(customerId) }
 
         fun customerId(customerId: Optional<String>) = customerId(customerId.orElse(null))
 
+        fun customerId(customerId: JsonField<String>) = apply { body.customerId(customerId) }
+
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
@@ -1169,10 +2082,20 @@ constructor(
         fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
             defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+            body.defaultInvoiceMemo(defaultInvoiceMemo)
+        }
+
         fun endDate(endDate: OffsetDateTime?) = apply { body.endDate(endDate) }
 
         fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
+        fun endDate(endDate: JsonField<OffsetDateTime>) = apply { body.endDate(endDate) }
+
         fun externalCustomerId(externalCustomerId: String?) = apply {
             body.externalCustomerId(externalCustomerId)
         }
@@ -1180,6 +2103,10 @@ constructor(
         fun externalCustomerId(externalCustomerId: Optional<String>) =
             externalCustomerId(externalCustomerId.orElse(null))
 
+        fun externalCustomerId(externalCustomerId: JsonField<String>) = apply {
+            body.externalCustomerId(externalCustomerId)
+        }
+
         fun externalMarketplace(externalMarketplace: ExternalMarketplace?) = apply {
             body.externalMarketplace(externalMarketplace)
         }
@@ -1187,6 +2114,10 @@ constructor(
         fun externalMarketplace(externalMarketplace: Optional<ExternalMarketplace>) =
             externalMarketplace(externalMarketplace.orElse(null))
 
+        fun externalMarketplace(externalMarketplace: JsonField<ExternalMarketplace>) = apply {
+            body.externalMarketplace(externalMarketplace)
+        }
+
         fun externalMarketplaceReportingId(externalMarketplaceReportingId: String?) = apply {
             body.externalMarketplaceReportingId(externalMarketplaceReportingId)
         }
@@ -1194,6 +2125,11 @@ constructor(
         fun externalMarketplaceReportingId(externalMarketplaceReportingId: Optional<String>) =
             externalMarketplaceReportingId(externalMarketplaceReportingId.orElse(null))
 
+        fun externalMarketplaceReportingId(externalMarketplaceReportingId: JsonField<String>) =
+            apply {
+                body.externalMarketplaceReportingId(externalMarketplaceReportingId)
+            }
+
         /**
          * The external_plan_id of the plan that the given subscription should be switched to. Note
          * that either this property or `plan_id` must be specified.
@@ -1207,6 +2143,14 @@ constructor(
         fun externalPlanId(externalPlanId: Optional<String>) =
             externalPlanId(externalPlanId.orElse(null))
 
+        /**
+         * The external_plan_id of the plan that the given subscription should be switched to. Note
+         * that either this property or `plan_id` must be specified.
+         */
+        fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+            body.externalPlanId(externalPlanId)
+        }
+
         /**
          * An additional filter to apply to usage queries. This filter must be expressed as a
          * boolean
@@ -1223,6 +2167,14 @@ constructor(
          */
         fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+        /**
+         * An additional filter to apply to usage queries. This filter must be expressed as a
+         * boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+         * null, usage queries will not include any additional filter.
+         */
+        fun filter(filter: JsonField<String>) = apply { body.filter(filter) }
+
         /** The phase of the plan to start with */
         fun initialPhaseOrder(initialPhaseOrder: Long?) = apply {
             body.initialPhaseOrder(initialPhaseOrder)
@@ -1237,6 +2189,11 @@ constructor(
         fun initialPhaseOrder(initialPhaseOrder: Optional<Long>) =
             initialPhaseOrder(initialPhaseOrder.orElse(null) as Long?)
 
+        /** The phase of the plan to start with */
+        fun initialPhaseOrder(initialPhaseOrder: JsonField<Long>) = apply {
+            body.initialPhaseOrder(initialPhaseOrder)
+        }
+
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
          * for the subscription. If not specified, invoices will only be issued at the end of the
@@ -1254,6 +2211,15 @@ constructor(
         fun invoicingThreshold(invoicingThreshold: Optional<String>) =
             invoicingThreshold(invoicingThreshold.orElse(null))
 
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+            body.invoicingThreshold(invoicingThreshold)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -1268,6 +2234,13 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
@@ -1290,6 +2263,13 @@ constructor(
         @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
         fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+         * provided, this defaults to the value specified in the plan.
+         */
+        fun netTerms(netTerms: JsonField<Long>) = apply { body.netTerms(netTerms) }
+
         fun perCreditOverageAmount(perCreditOverageAmount: Double?) = apply {
             body.perCreditOverageAmount(perCreditOverageAmount)
         }
@@ -1301,6 +2281,10 @@ constructor(
         fun perCreditOverageAmount(perCreditOverageAmount: Optional<Double>) =
             perCreditOverageAmount(perCreditOverageAmount.orElse(null) as Double?)
 
+        fun perCreditOverageAmount(perCreditOverageAmount: JsonField<Double>) = apply {
+            body.perCreditOverageAmount(perCreditOverageAmount)
+        }
+
         /**
          * The plan that the given subscription should be switched to. Note that either this
          * property or `external_plan_id` must be specified.
@@ -1313,6 +2297,12 @@ constructor(
          */
         fun planId(planId: Optional<String>) = planId(planId.orElse(null))
 
+        /**
+         * The plan that the given subscription should be switched to. Note that either this
+         * property or `external_plan_id` must be specified.
+         */
+        fun planId(planId: JsonField<String>) = apply { body.planId(planId) }
+
         /**
          * Specifies which version of the plan to subscribe to. If null, the default version will be
          * used.
@@ -1336,6 +2326,14 @@ constructor(
         fun planVersionNumber(planVersionNumber: Optional<Long>) =
             planVersionNumber(planVersionNumber.orElse(null) as Long?)
 
+        /**
+         * Specifies which version of the plan to subscribe to. If null, the default version will be
+         * used.
+         */
+        fun planVersionNumber(planVersionNumber: JsonField<Long>) = apply {
+            body.planVersionNumber(planVersionNumber)
+        }
+
         /** Optionally provide a list of overrides for prices on the plan */
         fun priceOverrides(priceOverrides: List<JsonValue>?) = apply {
             body.priceOverrides(priceOverrides)
@@ -1345,6 +2343,11 @@ constructor(
         fun priceOverrides(priceOverrides: Optional<List<JsonValue>>) =
             priceOverrides(priceOverrides.orElse(null))
 
+        /** Optionally provide a list of overrides for prices on the plan */
+        fun priceOverrides(priceOverrides: JsonField<List<JsonValue>>) = apply {
+            body.priceOverrides(priceOverrides)
+        }
+
         /** Optionally provide a list of overrides for prices on the plan */
         fun addPriceOverride(priceOverride: JsonValue) = apply {
             body.addPriceOverride(priceOverride)
@@ -1365,6 +2368,14 @@ constructor(
         fun removeAdjustments(removeAdjustments: Optional<List<RemoveAdjustment>>) =
             removeAdjustments(removeAdjustments.orElse(null))
 
+        /**
+         * Plan adjustments to be removed from the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun removeAdjustments(removeAdjustments: JsonField<List<RemoveAdjustment>>) = apply {
+            body.removeAdjustments(removeAdjustments)
+        }
+
         /**
          * Plan adjustments to be removed from the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
@@ -1388,6 +2399,14 @@ constructor(
         fun removePrices(removePrices: Optional<List<RemovePrice>>) =
             removePrices(removePrices.orElse(null))
 
+        /**
+         * Plan prices to be removed from the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun removePrices(removePrices: JsonField<List<RemovePrice>>) = apply {
+            body.removePrices(removePrices)
+        }
+
         /**
          * Plan prices to be removed from the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
@@ -1409,6 +2428,14 @@ constructor(
         fun replaceAdjustments(replaceAdjustments: Optional<List<ReplaceAdjustment>>) =
             replaceAdjustments(replaceAdjustments.orElse(null))
 
+        /**
+         * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+         * available for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replaceAdjustments(replaceAdjustments: JsonField<List<ReplaceAdjustment>>) = apply {
+            body.replaceAdjustments(replaceAdjustments)
+        }
+
         /**
          * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
          * available for accounts that have migrated off of legacy subscription overrides)
@@ -1432,6 +2459,14 @@ constructor(
         fun replacePrices(replacePrices: Optional<List<ReplacePrice>>) =
             replacePrices(replacePrices.orElse(null))
 
+        /**
+         * Plan prices to be replaced with additional prices on the subscription. (Only available
+         * for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replacePrices(replacePrices: JsonField<List<ReplacePrice>>) = apply {
+            body.replacePrices(replacePrices)
+        }
+
         /**
          * Plan prices to be replaced with additional prices on the subscription. (Only available
          * for accounts that have migrated off of legacy subscription overrides)
@@ -1444,6 +2479,8 @@ constructor(
 
         fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+        fun startDate(startDate: JsonField<OffsetDateTime>) = apply { body.startDate(startDate) }
+
         /**
          * The duration of the trial period in days. If not provided, this defaults to the value
          * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
@@ -1467,6 +2504,33 @@ constructor(
         fun trialDurationDays(trialDurationDays: Optional<Long>) =
             trialDurationDays(trialDurationDays.orElse(null) as Long?)
 
+        /**
+         * The duration of the trial period in days. If not provided, this defaults to the value
+         * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+         */
+        fun trialDurationDays(trialDurationDays: JsonField<Long>) = apply {
+            body.trialDurationDays(trialDurationDays)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -1565,25 +2629,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionCreateParams =
             SubscriptionCreateParams(
                 body.build(),
@@ -1596,16 +2641,49 @@ constructor(
     class AddAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment") private val adjustment: Adjustment,
-        @JsonProperty("end_date") private val endDate: OffsetDateTime?,
-        @JsonProperty("plan_phase_order") private val planPhaseOrder: Long?,
-        @JsonProperty("start_date") private val startDate: OffsetDateTime?,
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        private val adjustment: JsonField<Adjustment> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        private val planPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The definition of a new adjustment to create and add to the subscription. */
-        @JsonProperty("adjustment") fun adjustment(): Adjustment = adjustment
+        fun adjustment(): Adjustment = adjustment.getRequired("adjustment")
+
+        /**
+         * The end date of the adjustment interval. This is the date that the adjustment will stop
+         * affecting prices on the subscription. If null, the adjustment will start when the phase
+         * or subscription starts.
+         */
+        fun endDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The phase to add this adjustment to. */
+        fun planPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(planPhaseOrder.getNullable("plan_phase_order"))
+
+        /**
+         * The start date of the adjustment interval. This is the date that the adjustment will
+         * start affecting prices on the subscription. If null, the adjustment will start when the
+         * phase or subscription starts.
+         */
+        fun startDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
+        /** The definition of a new adjustment to create and add to the subscription. */
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /**
          * The end date of the adjustment interval. This is the date that the adjustment will stop
@@ -1613,11 +2691,13 @@ constructor(
          * or subscription starts.
          */
         @JsonProperty("end_date")
-        fun endDate(): Optional<OffsetDateTime> = Optional.ofNullable(endDate)
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The phase to add this adjustment to. */
         @JsonProperty("plan_phase_order")
-        fun planPhaseOrder(): Optional<Long> = Optional.ofNullable(planPhaseOrder)
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
         /**
          * The start date of the adjustment interval. This is the date that the adjustment will
@@ -1625,12 +2705,25 @@ constructor(
          * phase or subscription starts.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<OffsetDateTime> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddAdjustment = apply {
+            if (!validated) {
+                adjustment()
+                endDate()
+                planPhaseOrder()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1640,10 +2733,10 @@ constructor(
 
         class Builder {
 
-            private var adjustment: Adjustment? = null
-            private var endDate: OffsetDateTime? = null
-            private var planPhaseOrder: Long? = null
-            private var startDate: OffsetDateTime? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1656,34 +2749,34 @@ constructor(
             }
 
             /** The definition of a new adjustment to create and add to the subscription. */
-            fun adjustment(adjustment: Adjustment) = apply { this.adjustment = adjustment }
+            fun adjustment(adjustment: Adjustment) = adjustment(JsonField.of(adjustment))
 
-            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewPercentageDiscount(newPercentageDiscount)
+            /** The definition of a new adjustment to create and add to the subscription. */
+            fun adjustment(adjustment: JsonField<Adjustment>) = apply {
+                this.adjustment = adjustment
             }
 
-            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewUsageDiscount(newUsageDiscount)
-            }
+            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) =
+                adjustment(Adjustment.ofNewPercentageDiscount(newPercentageDiscount))
 
-            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) = apply {
-                this.adjustment = Adjustment.ofNewAmountDiscount(newAmountDiscount)
-            }
+            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) =
+                adjustment(Adjustment.ofNewUsageDiscount(newUsageDiscount))
 
-            fun adjustment(newMinimum: Adjustment.NewMinimum) = apply {
-                this.adjustment = Adjustment.ofNewMinimum(newMinimum)
-            }
+            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) =
+                adjustment(Adjustment.ofNewAmountDiscount(newAmountDiscount))
 
-            fun adjustment(newMaximum: Adjustment.NewMaximum) = apply {
-                this.adjustment = Adjustment.ofNewMaximum(newMaximum)
-            }
+            fun adjustment(newMinimum: Adjustment.NewMinimum) =
+                adjustment(Adjustment.ofNewMinimum(newMinimum))
+
+            fun adjustment(newMaximum: Adjustment.NewMaximum) =
+                adjustment(Adjustment.ofNewMaximum(newMaximum))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
              * stop affecting prices on the subscription. If null, the adjustment will start when
              * the phase or subscription starts.
              */
-            fun endDate(endDate: OffsetDateTime?) = apply { this.endDate = endDate }
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
@@ -1692,10 +2785,16 @@ constructor(
              */
             fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
+            /**
+             * The end date of the adjustment interval. This is the date that the adjustment will
+             * stop affecting prices on the subscription. If null, the adjustment will start when
+             * the phase or subscription starts.
+             */
+            fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
+
             /** The phase to add this adjustment to. */
-            fun planPhaseOrder(planPhaseOrder: Long?) = apply {
-                this.planPhaseOrder = planPhaseOrder
-            }
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
 
             /** The phase to add this adjustment to. */
             fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
@@ -1705,12 +2804,17 @@ constructor(
             fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
                 planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
+            /** The phase to add this adjustment to. */
+            fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
+                this.planPhaseOrder = planPhaseOrder
+            }
+
             /**
              * The start date of the adjustment interval. This is the date that the adjustment will
              * start affecting prices on the subscription. If null, the adjustment will start when
              * the phase or subscription starts.
              */
-            fun startDate(startDate: OffsetDateTime?) = apply { this.startDate = startDate }
+            fun startDate(startDate: OffsetDateTime?) = startDate(JsonField.ofNullable(startDate))
 
             /**
              * The start date of the adjustment interval. This is the date that the adjustment will
@@ -1719,6 +2823,15 @@ constructor(
              */
             fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+            /**
+             * The start date of the adjustment interval. This is the date that the adjustment will
+             * start affecting prices on the subscription. If null, the adjustment will start when
+             * the phase or subscription starts.
+             */
+            fun startDate(startDate: JsonField<OffsetDateTime>) = apply {
+                this.startDate = startDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1761,6 +2874,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newPercentageDiscount(): Optional<NewPercentageDiscount> =
                 Optional.ofNullable(newPercentageDiscount)
 
@@ -1811,6 +2926,26 @@ constructor(
                 }
             }
 
+            fun validate(): Adjustment = apply {
+                if (!validated) {
+                    if (
+                        newPercentageDiscount == null &&
+                            newUsageDiscount == null &&
+                            newAmountDiscount == null &&
+                            newMinimum == null &&
+                            newMaximum == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Adjustment: $_json")
+                    }
+                    newPercentageDiscount?.validate()
+                    newUsageDiscount?.validate()
+                    newAmountDiscount?.validate()
+                    newMinimum?.validate()
+                    newMaximum?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -1880,29 +3015,40 @@ constructor(
 
                     when (adjustmentType) {
                         "percentage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>())?.let {
-                                return Adjustment(newPercentageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newPercentageDiscount = it, _json = json)
+                                }
                         }
                         "usage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>())?.let {
-                                return Adjustment(newUsageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newUsageDiscount = it, _json = json)
+                                }
                         }
                         "amount_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>())?.let {
-                                return Adjustment(newAmountDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newAmountDiscount = it, _json = json)
+                                }
                         }
                         "minimum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMinimum>())?.let {
-                                return Adjustment(newMinimum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMinimum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMinimum = it, _json = json)
+                                }
                         }
                         "maximum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMaximum>())?.let {
-                                return Adjustment(newMaximum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMaximum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMaximum = it, _json = json)
+                                }
                         }
                     }
 
@@ -1936,35 +3082,75 @@ constructor(
             class NewPercentageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewPercentageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        percentageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1974,47 +3160,58 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var percentageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newPercentageDiscount: NewPercentageDiscount) = apply {
                         adjustmentType = newPercentageDiscount.adjustmentType
-                        appliesToPriceIds = newPercentageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newPercentageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         percentageDiscount = newPercentageDiscount.percentageDiscount
                         isInvoiceLevel = newPercentageDiscount.isInvoiceLevel
                         additionalProperties =
                             newPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
-                        this.percentageDiscount = percentageDiscount
-                    }
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                        this.percentageDiscount = percentageDiscount
                     }
 
                     /**
@@ -2022,15 +3219,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2062,7 +3259,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(percentageDiscount) {
                                 "`percentageDiscount` is required but was not set"
                             },
@@ -2145,34 +3342,74 @@ constructor(
             class NewUsageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewUsageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        usageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2182,46 +3419,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var usageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var usageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newUsageDiscount: NewUsageDiscount) = apply {
                         adjustmentType = newUsageDiscount.adjustmentType
-                        appliesToPriceIds = newUsageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newUsageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         usageDiscount = newUsageDiscount.usageDiscount
                         isInvoiceLevel = newUsageDiscount.isInvoiceLevel
                         additionalProperties = newUsageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun usageDiscount(usageDiscount: Double) = apply {
-                        this.usageDiscount = usageDiscount
-                    }
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                        this.usageDiscount = usageDiscount
                     }
 
                     /**
@@ -2229,15 +3477,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2269,7 +3517,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(usageDiscount) {
                                 "`usageDiscount` is required but was not set"
                             },
@@ -2352,34 +3600,74 @@ constructor(
             class NewAmountDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("amount_discount") private val amountDiscount: String,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
-                @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewAmountDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        amountDiscount()
+                        appliesToPriceIds()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2389,46 +3677,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var amountDiscount: String? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newAmountDiscount: NewAmountDiscount) = apply {
                         adjustmentType = newAmountDiscount.adjustmentType
                         amountDiscount = newAmountDiscount.amountDiscount
-                        appliesToPriceIds = newAmountDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newAmountDiscount.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = newAmountDiscount.isInvoiceLevel
                         additionalProperties = newAmountDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
-                    fun amountDiscount(amountDiscount: String) = apply {
+                    fun amountDiscount(amountDiscount: String) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
-                    }
-
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2436,15 +3735,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2479,7 +3778,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             isInvoiceLevel,
                             additionalProperties.toImmutable(),
                         )
@@ -2559,38 +3858,84 @@ constructor(
             class NewMinimum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /** The item ID that revenue from this minimum will be attributed to. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMinimum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        itemId()
+                        minimumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2600,51 +3945,64 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var itemId: String? = null
-                    private var minimumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMinimum: NewMinimum) = apply {
                         adjustmentType = newMinimum.adjustmentType
-                        appliesToPriceIds = newMinimum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMinimum.appliesToPriceIds.map { it.toMutableList() }
                         itemId = newMinimum.itemId
                         minimumAmount = newMinimum.minimumAmount
                         isInvoiceLevel = newMinimum.isInvoiceLevel
                         additionalProperties = newMinimum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /** The item ID that revenue from this minimum will be attributed to. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun minimumAmount(minimumAmount: String) = apply {
-                        this.minimumAmount = minimumAmount
-                    }
+                    /** The item ID that revenue from this minimum will be attributed to. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                        this.minimumAmount = minimumAmount
                     }
 
                     /**
@@ -2652,15 +4010,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2692,7 +4050,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(itemId) { "`itemId` is required but was not set" },
                             checkNotNull(minimumAmount) {
                                 "`minimumAmount` is required but was not set"
@@ -2776,34 +4134,74 @@ constructor(
             class NewMaximum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("maximum_amount") private val maximumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun maximumAmount(): String = maximumAmount.getRequired("maximum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("maximum_amount") fun maximumAmount(): String = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMaximum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        maximumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2813,46 +4211,56 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var maximumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMaximum: NewMaximum) = apply {
                         adjustmentType = newMaximum.adjustmentType
-                        appliesToPriceIds = newMaximum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMaximum.appliesToPriceIds.map { it.toMutableList() }
                         maximumAmount = newMaximum.maximumAmount
                         isInvoiceLevel = newMaximum.isInvoiceLevel
                         additionalProperties = newMaximum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun maximumAmount(maximumAmount: String) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String) =
+                        maximumAmount(JsonField.of(maximumAmount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
                     /**
@@ -2860,15 +4268,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2900,7 +4308,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(maximumAmount) {
                                 "`maximumAmount` is required but was not set"
                             },
@@ -3002,71 +4410,161 @@ constructor(
     class AddPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("discounts") private val discounts: List<Discount>?,
-        @JsonProperty("end_date") private val endDate: OffsetDateTime?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-        @JsonProperty("minimum_amount") private val minimumAmount: String?,
-        @JsonProperty("plan_phase_order") private val planPhaseOrder: Long?,
-        @JsonProperty("price") private val price: Price?,
-        @JsonProperty("price_id") private val priceId: String?,
-        @JsonProperty("start_date") private val startDate: OffsetDateTime?,
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        private val discounts: JsonField<List<Discount>> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        private val planPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("price")
+        @ExcludeMissing
+        private val price: JsonField<Price> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this price.
+         */
+        fun discounts(): Optional<List<Discount>> =
+            Optional.ofNullable(discounts.getNullable("discounts"))
+
+        /**
+         * The end date of the price interval. This is the date that the price will stop billing on
+         * the subscription. If null, billing will end when the phase or subscription ends.
+         */
+        fun endDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The external price id of the price to add to the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
+         * price.
+         */
+        fun maximumAmount(): Optional<String> =
+            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
+         * price.
+         */
+        fun minimumAmount(): Optional<String> =
+            Optional.ofNullable(minimumAmount.getNullable("minimum_amount"))
+
+        /** The phase to add this price to. */
+        fun planPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(planPhaseOrder.getNullable("plan_phase_order"))
+
+        /** The definition of a new price to create and add to the subscription. */
+        fun price(): Optional<Price> = Optional.ofNullable(price.getNullable("price"))
+
+        /** The id of the price to add to the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
+        /**
+         * The start date of the price interval. This is the date that the price will start billing
+         * on the subscription. If null, billing will start when the phase or subscription starts.
+         */
+        fun startDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this price.
          */
         @JsonProperty("discounts")
-        fun discounts(): Optional<List<Discount>> = Optional.ofNullable(discounts)
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         /**
          * The end date of the price interval. This is the date that the price will stop billing on
          * the subscription. If null, billing will end when the phase or subscription ends.
          */
         @JsonProperty("end_date")
-        fun endDate(): Optional<OffsetDateTime> = Optional.ofNullable(endDate)
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The external price id of the price to add to the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
          * price.
          */
         @JsonProperty("maximum_amount")
-        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
          * price.
          */
         @JsonProperty("minimum_amount")
-        fun minimumAmount(): Optional<String> = Optional.ofNullable(minimumAmount)
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The phase to add this price to. */
         @JsonProperty("plan_phase_order")
-        fun planPhaseOrder(): Optional<Long> = Optional.ofNullable(planPhaseOrder)
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
         /** The definition of a new price to create and add to the subscription. */
-        @JsonProperty("price") fun price(): Optional<Price> = Optional.ofNullable(price)
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /** The id of the price to add to the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         /**
          * The start date of the price interval. This is the date that the price will start billing
          * on the subscription. If null, billing will start when the phase or subscription starts.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<OffsetDateTime> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddPrice = apply {
+            if (!validated) {
+                discounts().map { it.forEach { it.validate() } }
+                endDate()
+                externalPriceId()
+                maximumAmount()
+                minimumAmount()
+                planPhaseOrder()
+                price()
+                priceId()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -3076,20 +4574,20 @@ constructor(
 
         class Builder {
 
-            private var discounts: MutableList<Discount>? = null
-            private var endDate: OffsetDateTime? = null
-            private var externalPriceId: String? = null
-            private var maximumAmount: String? = null
-            private var minimumAmount: String? = null
-            private var planPhaseOrder: Long? = null
-            private var price: Price? = null
-            private var priceId: String? = null
-            private var startDate: OffsetDateTime? = null
+            private var discounts: JsonField<MutableList<Discount>>? = null
+            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var price: JsonField<Price> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
+            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(addPrice: AddPrice) = apply {
-                discounts = addPrice.discounts?.toMutableList()
+                discounts = addPrice.discounts.map { it.toMutableList() }
                 endDate = addPrice.endDate
                 externalPriceId = addPrice.externalPriceId
                 maximumAmount = addPrice.maximumAmount
@@ -3105,9 +4603,7 @@ constructor(
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
              * price.
              */
-            fun discounts(discounts: List<Discount>?) = apply {
-                this.discounts = discounts?.toMutableList()
-            }
+            fun discounts(discounts: List<Discount>?) = discounts(JsonField.ofNullable(discounts))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
@@ -3115,19 +4611,36 @@ constructor(
              */
             fun discounts(discounts: Optional<List<Discount>>) = discounts(discounts.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
+             * price.
+             */
+            fun discounts(discounts: JsonField<List<Discount>>) = apply {
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
              * price.
              */
             fun addDiscount(discount: Discount) = apply {
-                discounts = (discounts ?: mutableListOf()).apply { add(discount) }
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
              * on the subscription. If null, billing will end when the phase or subscription ends.
              */
-            fun endDate(endDate: OffsetDateTime?) = apply { this.endDate = endDate }
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
@@ -3135,20 +4648,31 @@ constructor(
              */
             fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
+            /**
+             * The end date of the price interval. This is the date that the price will stop billing
+             * on the subscription. If null, billing will end when the phase or subscription ends.
+             */
+            fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
+
             /** The external price id of the price to add to the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to add to the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** The external price id of the price to add to the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
              * price.
              */
-            fun maximumAmount(maximumAmount: String?) = apply { this.maximumAmount = maximumAmount }
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
@@ -3157,11 +4681,20 @@ constructor(
             fun maximumAmount(maximumAmount: Optional<String>) =
                 maximumAmount(maximumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
+             * price.
+             */
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
              * price.
              */
-            fun minimumAmount(minimumAmount: String?) = apply { this.minimumAmount = minimumAmount }
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
@@ -3170,11 +4703,18 @@ constructor(
             fun minimumAmount(minimumAmount: Optional<String>) =
                 minimumAmount(minimumAmount.orElse(null))
 
-            /** The phase to add this price to. */
-            fun planPhaseOrder(planPhaseOrder: Long?) = apply {
-                this.planPhaseOrder = planPhaseOrder
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
+             * price.
+             */
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
             }
 
+            /** The phase to add this price to. */
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
             /** The phase to add this price to. */
             fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
 
@@ -3183,144 +4723,144 @@ constructor(
             fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
                 planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
+            /** The phase to add this price to. */
+            fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
+                this.planPhaseOrder = planPhaseOrder
+            }
+
             /** The definition of a new price to create and add to the subscription. */
-            fun price(price: Price?) = apply { this.price = price }
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /** The definition of a new price to create and add to the subscription. */
             fun price(price: Optional<Price>) = price(price.orElse(null))
 
-            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) = apply {
-                this.price = Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice)
-            }
+            /** The definition of a new price to create and add to the subscription. */
+            fun price(price: JsonField<Price>) = apply { this.price = price }
 
-            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) = apply {
-                this.price = Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice)
-            }
+            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) =
+                price(Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice))
 
-            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) = apply {
-                this.price = Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice)
-            }
+            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) =
+                price(Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice))
 
-            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice)
-            }
+            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) =
+                price(Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice))
 
-            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice)
-            }
+            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) =
+                price(Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice))
 
-            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice)
-            }
+            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) =
+                price(Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice))
 
-            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice)
-            }
+            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) =
+                price(Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice))
 
-            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice)
-            }
+            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) =
+                price(Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice))
+
+            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) =
+                price(Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice))
 
             fun price(
                 newSubscriptionThresholdTotalAmountPrice:
                     Price.NewSubscriptionThresholdTotalAmountPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionThresholdTotalAmountPrice(
                         newSubscriptionThresholdTotalAmountPrice
                     )
-            }
+                )
 
             fun price(newSubscriptionTieredPackagePrice: Price.NewSubscriptionTieredPackagePrice) =
-                apply {
-                    this.price =
-                        Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice)
-                }
+                price(Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice))
 
             fun price(
                 newSubscriptionTieredWithMinimumPrice: Price.NewSubscriptionTieredWithMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTieredWithMinimumPrice(
                         newSubscriptionTieredWithMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithPercentPrice: Price.NewSubscriptionUnitWithPercentPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithPercentPrice(newSubscriptionUnitWithPercentPrice)
-            }
+                )
 
             fun price(
                 newSubscriptionPackageWithAllocationPrice:
                     Price.NewSubscriptionPackageWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionPackageWithAllocationPrice(
                         newSubscriptionPackageWithAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionTierWithProrationPrice: Price.NewSubscriptionTierWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTierWithProrationPrice(
                         newSubscriptionTierWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithProrationPrice: Price.NewSubscriptionUnitWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithProrationPrice(
                         newSubscriptionUnitWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedAllocationPrice: Price.NewSubscriptionGroupedAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedAllocationPrice(
                         newSubscriptionGroupedAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedWithProratedMinimumPrice:
                     Price.NewSubscriptionGroupedWithProratedMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedWithProratedMinimumPrice(
                         newSubscriptionGroupedWithProratedMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionBulkWithProrationPrice: Price.NewSubscriptionBulkWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionBulkWithProrationPrice(
                         newSubscriptionBulkWithProrationPrice
                     )
-            }
+                )
 
             /** The id of the price to add to the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to add to the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to add to the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             /**
              * The start date of the price interval. This is the date that the price will start
              * billing on the subscription. If null, billing will start when the phase or
              * subscription starts.
              */
-            fun startDate(startDate: OffsetDateTime?) = apply { this.startDate = startDate }
+            fun startDate(startDate: OffsetDateTime?) = startDate(JsonField.ofNullable(startDate))
 
             /**
              * The start date of the price interval. This is the date that the price will start
@@ -3329,6 +4869,15 @@ constructor(
              */
             fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+            /**
+             * The start date of the price interval. This is the date that the price will start
+             * billing on the subscription. If null, billing will start when the phase or
+             * subscription starts.
+             */
+            fun startDate(startDate: JsonField<OffsetDateTime>) = apply {
+                this.startDate = startDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -3350,7 +4899,7 @@ constructor(
 
             fun build(): AddPrice =
                 AddPrice(
-                    discounts?.toImmutable(),
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     endDate,
                     externalPriceId,
                     maximumAmount,
@@ -3367,37 +4916,81 @@ constructor(
         class Discount
         @JsonCreator
         private constructor(
-            @JsonProperty("discount_type") private val discountType: DiscountType,
-            @JsonProperty("amount_discount") private val amountDiscount: String?,
-            @JsonProperty("percentage_discount") private val percentageDiscount: Double?,
-            @JsonProperty("usage_discount") private val usageDiscount: Double?,
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            private val amountDiscount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("percentage_discount")
+            @ExcludeMissing
+            private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            private val usageDiscount: JsonField<Double> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+            /** Only available if discount_type is `amount`. */
+            fun amountDiscount(): Optional<String> =
+                Optional.ofNullable(amountDiscount.getNullable("amount_discount"))
+
+            /**
+             * Only available if discount_type is `percentage`. This is a number between 0 and 1.
+             */
+            fun percentageDiscount(): Optional<Double> =
+                Optional.ofNullable(percentageDiscount.getNullable("percentage_discount"))
+
+            /**
+             * Only available if discount_type is `usage`. Number of usage units that this discount
+             * is for
+             */
+            fun usageDiscount(): Optional<Double> =
+                Optional.ofNullable(usageDiscount.getNullable("usage_discount"))
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** Only available if discount_type is `amount`. */
             @JsonProperty("amount_discount")
-            fun amountDiscount(): Optional<String> = Optional.ofNullable(amountDiscount)
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /**
              * Only available if discount_type is `percentage`. This is a number between 0 and 1.
              */
             @JsonProperty("percentage_discount")
-            fun percentageDiscount(): Optional<Double> = Optional.ofNullable(percentageDiscount)
+            @ExcludeMissing
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
             @JsonProperty("usage_discount")
-            fun usageDiscount(): Optional<Double> = Optional.ofNullable(usageDiscount)
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Discount = apply {
+                if (!validated) {
+                    discountType()
+                    amountDiscount()
+                    percentageDiscount()
+                    usageDiscount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3407,10 +5000,10 @@ constructor(
 
             class Builder {
 
-                private var discountType: DiscountType? = null
-                private var amountDiscount: String? = null
-                private var percentageDiscount: Double? = null
-                private var usageDiscount: Double? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var amountDiscount: JsonField<String> = JsonMissing.of()
+                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+                private var usageDiscount: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3422,26 +5015,32 @@ constructor(
                     additionalProperties = discount.additionalProperties.toMutableMap()
                 }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
                 /** Only available if discount_type is `amount`. */
-                fun amountDiscount(amountDiscount: String?) = apply {
-                    this.amountDiscount = amountDiscount
-                }
+                fun amountDiscount(amountDiscount: String?) =
+                    amountDiscount(JsonField.ofNullable(amountDiscount))
 
                 /** Only available if discount_type is `amount`. */
                 fun amountDiscount(amountDiscount: Optional<String>) =
                     amountDiscount(amountDiscount.orElse(null))
 
+                /** Only available if discount_type is `amount`. */
+                fun amountDiscount(amountDiscount: JsonField<String>) = apply {
+                    this.amountDiscount = amountDiscount
+                }
+
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
                  * and 1.
                  */
-                fun percentageDiscount(percentageDiscount: Double?) = apply {
-                    this.percentageDiscount = percentageDiscount
-                }
+                fun percentageDiscount(percentageDiscount: Double?) =
+                    percentageDiscount(JsonField.ofNullable(percentageDiscount))
 
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
@@ -3458,13 +5057,20 @@ constructor(
                 fun percentageDiscount(percentageDiscount: Optional<Double>) =
                     percentageDiscount(percentageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `percentage`. This is a number between 0
+                 * and 1.
+                 */
+                fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                    this.percentageDiscount = percentageDiscount
+                }
+
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
                  * discount is for
                  */
-                fun usageDiscount(usageDiscount: Double?) = apply {
-                    this.usageDiscount = usageDiscount
-                }
+                fun usageDiscount(usageDiscount: Double?) =
+                    usageDiscount(JsonField.ofNullable(usageDiscount))
 
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
@@ -3480,6 +5086,14 @@ constructor(
                 fun usageDiscount(usageDiscount: Optional<Double>) =
                     usageDiscount(usageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `usage`. Number of usage units that this
+                 * discount is for
+                 */
+                fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                    this.usageDiscount = usageDiscount
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -3637,6 +5251,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newSubscriptionUnitPrice(): Optional<NewSubscriptionUnitPrice> =
                 Optional.ofNullable(newSubscriptionUnitPrice)
 
@@ -3885,6 +5501,52 @@ constructor(
                 }
             }
 
+            fun validate(): Price = apply {
+                if (!validated) {
+                    if (
+                        newSubscriptionUnitPrice == null &&
+                            newSubscriptionPackagePrice == null &&
+                            newSubscriptionMatrixPrice == null &&
+                            newSubscriptionTieredPrice == null &&
+                            newSubscriptionTieredBpsPrice == null &&
+                            newSubscriptionBpsPrice == null &&
+                            newSubscriptionBulkBpsPrice == null &&
+                            newSubscriptionBulkPrice == null &&
+                            newSubscriptionThresholdTotalAmountPrice == null &&
+                            newSubscriptionTieredPackagePrice == null &&
+                            newSubscriptionTieredWithMinimumPrice == null &&
+                            newSubscriptionUnitWithPercentPrice == null &&
+                            newSubscriptionPackageWithAllocationPrice == null &&
+                            newSubscriptionTierWithProrationPrice == null &&
+                            newSubscriptionUnitWithProrationPrice == null &&
+                            newSubscriptionGroupedAllocationPrice == null &&
+                            newSubscriptionGroupedWithProratedMinimumPrice == null &&
+                            newSubscriptionBulkWithProrationPrice == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Price: $_json")
+                    }
+                    newSubscriptionUnitPrice?.validate()
+                    newSubscriptionPackagePrice?.validate()
+                    newSubscriptionMatrixPrice?.validate()
+                    newSubscriptionTieredPrice?.validate()
+                    newSubscriptionTieredBpsPrice?.validate()
+                    newSubscriptionBpsPrice?.validate()
+                    newSubscriptionBulkBpsPrice?.validate()
+                    newSubscriptionBulkPrice?.validate()
+                    newSubscriptionThresholdTotalAmountPrice?.validate()
+                    newSubscriptionTieredPackagePrice?.validate()
+                    newSubscriptionTieredWithMinimumPrice?.validate()
+                    newSubscriptionUnitWithPercentPrice?.validate()
+                    newSubscriptionPackageWithAllocationPrice?.validate()
+                    newSubscriptionTierWithProrationPrice?.validate()
+                    newSubscriptionUnitWithProrationPrice?.validate()
+                    newSubscriptionGroupedAllocationPrice?.validate()
+                    newSubscriptionGroupedWithProratedMinimumPrice?.validate()
+                    newSubscriptionBulkWithProrationPrice?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -4153,55 +5815,76 @@ constructor(
 
                     when (modelType) {
                         "unit" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>())?.let {
-                                return Price(newSubscriptionUnitPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionUnitPrice = it, _json = json)
+                                }
                         }
                         "package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionPackagePrice = it, _json = json)
                                 }
                         }
                         "matrix" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionMatrixPrice = it, _json = json)
                                 }
                         }
                         "tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredPrice = it, _json = json)
                                 }
                         }
                         "tiered_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredBpsPrice = it, _json = json)
                                 }
                         }
                         "bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>())?.let {
-                                return Price(newSubscriptionBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionBulkBpsPrice = it, _json = json)
                                 }
                         }
                         "bulk" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>())?.let {
-                                return Price(newSubscriptionBulkPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBulkPrice = it, _json = json)
+                                }
                         }
                         "threshold_total_amount" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionThresholdTotalAmountPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionThresholdTotalAmountPrice = it,
@@ -4213,7 +5896,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredPackagePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredPackagePrice = it,
@@ -4225,7 +5910,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredWithMinimumPrice = it,
@@ -4237,7 +5924,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithPercentPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithPercentPrice = it,
@@ -4249,7 +5938,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionPackageWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionPackageWithAllocationPrice = it,
@@ -4261,7 +5952,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTierWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTierWithProrationPrice = it,
@@ -4273,7 +5966,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithProrationPrice = it,
@@ -4285,7 +5980,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedAllocationPrice = it,
@@ -4297,7 +5994,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedWithProratedMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedWithProratedMinimumPrice = it,
@@ -4309,7 +6008,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionBulkWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionBulkWithProrationPrice = it,
@@ -4379,96 +6080,229 @@ constructor(
             class NewSubscriptionUnitPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+                fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -4476,19 +6310,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4498,22 +6358,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitConfig: UnitConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitConfig: JsonField<UnitConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -4541,25 +6404,41 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
-                    fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                    fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
+
+                    fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                        this.unitConfig = unitConfig
+                    }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -4568,13 +6447,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -4591,13 +6477,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -4607,12 +6501,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -4627,11 +6528,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -4639,22 +6547,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -4671,22 +6588,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -4696,12 +6628,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -4710,11 +6650,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -4723,6 +6671,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -4905,18 +6861,34 @@ constructor(
                 class UnitConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Rate per unit of usage */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Rate per unit of usage */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitConfig = apply {
+                        if (!validated) {
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4926,7 +6898,7 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4937,7 +6909,12 @@ constructor(
                         }
 
                         /** Rate per unit of usage */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Rate per unit of usage */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -4996,22 +6973,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5021,8 +7022,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5036,10 +7037,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -5160,22 +7168,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5185,8 +7217,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5201,10 +7233,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -5334,6 +7373,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5415,96 +7462,229 @@ constructor(
             class NewSubscriptionPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_config") private val packageConfig: PackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -5512,19 +7692,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5534,22 +7740,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageConfig: PackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageConfig: JsonField<PackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5578,17 +7787,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun packageConfig(packageConfig: PackageConfig) =
+                        packageConfig(JsonField.of(packageConfig))
 
-                    fun packageConfig(packageConfig: PackageConfig) = apply {
+                    fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                         this.packageConfig = packageConfig
                     }
 
@@ -5596,9 +7821,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -5607,13 +7831,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -5630,13 +7861,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -5646,12 +7885,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -5666,11 +7912,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -5678,22 +7931,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -5710,22 +7972,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -5735,12 +8012,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -5749,11 +8034,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -5762,6 +8055,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -5946,25 +8247,52 @@ constructor(
                 class PackageConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("package_amount") private val packageAmount: String,
-                    @JsonProperty("package_size") private val packageSize: Long,
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    private val packageAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    private val packageSize: JsonField<Long> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** A currency amount to rate usage by */
-                    @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                    fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                    /** A currency amount to rate usage by */
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    fun _packageAmount(): JsonField<String> = packageAmount
 
                     /**
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    fun _packageSize(): JsonField<Long> = packageSize
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageConfig = apply {
+                        if (!validated) {
+                            packageAmount()
+                            packageSize()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5974,8 +8302,8 @@ constructor(
 
                     class Builder {
 
-                        private var packageAmount: String? = null
-                        private var packageSize: Long? = null
+                        private var packageAmount: JsonField<String>? = null
+                        private var packageSize: JsonField<Long>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5987,7 +8315,11 @@ constructor(
                         }
 
                         /** A currency amount to rate usage by */
-                        fun packageAmount(packageAmount: String) = apply {
+                        fun packageAmount(packageAmount: String) =
+                            packageAmount(JsonField.of(packageAmount))
+
+                        /** A currency amount to rate usage by */
+                        fun packageAmount(packageAmount: JsonField<String>) = apply {
                             this.packageAmount = packageAmount
                         }
 
@@ -5995,7 +8327,13 @@ constructor(
                          * An integer amount to represent package size. For example, 1000 here would
                          * divide usage by 1000 before multiplying by package_amount in rating
                          */
-                        fun packageSize(packageSize: Long) = apply {
+                        fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                        /**
+                         * An integer amount to represent package size. For example, 1000 here would
+                         * divide usage by 1000 before multiplying by package_amount in rating
+                         */
+                        fun packageSize(packageSize: JsonField<Long>) = apply {
                             this.packageSize = packageSize
                         }
 
@@ -6059,22 +8397,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6084,8 +8446,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6099,10 +8461,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -6223,22 +8592,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6248,8 +8641,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6264,10 +8657,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -6397,6 +8797,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6478,96 +8886,229 @@ constructor(
             class NewSubscriptionMatrixPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -6575,19 +9116,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionMatrixPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        matrixConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6597,22 +9164,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var matrixConfig: MatrixConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6641,27 +9211,42 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixConfig(matrixConfig: MatrixConfig) =
+                        matrixConfig(JsonField.of(matrixConfig))
 
-                    fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                    fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                         this.matrixConfig = matrixConfig
                     }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -6670,13 +9255,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -6693,13 +9285,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -6709,12 +9309,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -6729,11 +9336,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -6741,22 +9355,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -6773,22 +9396,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -6798,12 +9436,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -6812,11 +9458,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -6825,6 +9479,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -6957,31 +9619,66 @@ constructor(
                 class MatrixConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixConfig = apply {
+                        if (!validated) {
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6991,17 +9688,17 @@ constructor(
 
                     class Builder {
 
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
                             defaultUnitAmount = matrixConfig.defaultUnitAmount
-                            dimensions = matrixConfig.dimensions.toMutableList()
-                            matrixValues = matrixConfig.matrixValues.toMutableList()
+                            dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                            matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -7009,29 +9706,61 @@ constructor(
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -7064,11 +9793,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -7078,28 +9807,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -7109,14 +9865,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -7127,8 +9884,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -7138,13 +9903,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -7175,7 +9950,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -7279,22 +10054,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7304,8 +10103,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7319,10 +10118,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7443,22 +10249,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7468,8 +10298,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7484,10 +10314,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7617,6 +10454,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7698,96 +10543,229 @@ constructor(
             class NewSubscriptionTieredPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+                fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -7795,19 +10773,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7817,22 +10821,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredConfig: TieredConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredConfig: JsonField<TieredConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7861,17 +10868,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredConfig(tieredConfig: TieredConfig) =
+                        tieredConfig(JsonField.of(tieredConfig))
 
-                    fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                    fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                         this.tieredConfig = tieredConfig
                     }
 
@@ -7879,9 +10902,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -7890,13 +10912,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -7913,13 +10942,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -7929,12 +10966,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -7949,11 +10993,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -7961,22 +11012,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -7993,22 +11053,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -8018,12 +11093,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -8032,11 +11115,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -8045,6 +11136,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -8229,18 +11328,34 @@ constructor(
                 class TieredConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8250,26 +11365,42 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredConfig: TieredConfig) = apply {
-                            tiers = tieredConfig.tiers.toMutableList()
+                            tiers = tieredConfig.tiers.map { it.toMutableList() }
                             additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                         }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for rating based on total usage quantities into the specified tier
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -8297,7 +11428,7 @@ constructor(
                         fun build(): TieredConfig =
                             TieredConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -8306,30 +11437,64 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("first_unit") private val firstUnit: Double,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("last_unit") private val lastUnit: Double?,
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("last_unit")
+                        @ExcludeMissing
+                        private val lastUnit: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                        fun firstUnit(): Double = firstUnit.getRequired("first_unit")
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(): Optional<Double> =
+                            Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        fun _firstUnit(): JsonField<Double> = firstUnit
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
                         @JsonProperty("last_unit")
-                        fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                        @ExcludeMissing
+                        fun _lastUnit(): JsonField<Double> = lastUnit
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                firstUnit()
+                                unitAmount()
+                                lastUnit()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -8339,9 +11504,9 @@ constructor(
 
                         class Builder {
 
-                            private var firstUnit: Double? = null
-                            private var unitAmount: String? = null
-                            private var lastUnit: Double? = null
+                            private var firstUnit: JsonField<Double>? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var lastUnit: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -8354,10 +11519,19 @@ constructor(
                             }
 
                             /** Inclusive tier starting value */
-                            fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                            fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                            /** Inclusive tier starting value */
+                            fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                                this.firstUnit = firstUnit
+                            }
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -8365,7 +11539,8 @@ constructor(
                              * Exclusive tier ending value. If null, this is treated as the last
                              * tier
                              */
-                            fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                            fun lastUnit(lastUnit: Double?) =
+                                lastUnit(JsonField.ofNullable(lastUnit))
 
                             /**
                              * Exclusive tier ending value. If null, this is treated as the last
@@ -8383,6 +11558,14 @@ constructor(
                             fun lastUnit(lastUnit: Optional<Double>) =
                                 lastUnit(lastUnit.orElse(null) as Double?)
 
+                            /**
+                             * Exclusive tier ending value. If null, this is treated as the last
+                             * tier
+                             */
+                            fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                                this.lastUnit = lastUnit
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -8462,22 +11645,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8487,8 +11694,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8502,10 +11709,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8626,22 +11840,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8651,8 +11889,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8667,10 +11905,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8800,6 +12045,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8881,97 +12134,230 @@ constructor(
             class NewSubscriptionTieredBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_bps_config")
+                @ExcludeMissing
+                private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredBpsConfig(): TieredBpsConfig =
+                    tieredBpsConfig.getRequired("tiered_bps_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_bps_config")
-                fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+                @ExcludeMissing
+                fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -8979,19 +12365,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredBpsPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredBpsConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9001,22 +12413,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredBpsConfig: TieredBpsConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9046,17 +12461,33 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                        tieredBpsConfig(JsonField.of(tieredBpsConfig))
 
-                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                    fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                         this.tieredBpsConfig = tieredBpsConfig
                     }
 
@@ -9064,9 +12495,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -9075,13 +12505,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -9098,13 +12535,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -9114,12 +12559,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -9134,11 +12586,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -9146,22 +12605,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -9178,22 +12646,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -9203,12 +12686,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -9217,11 +12708,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -9230,6 +12729,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -9414,7 +12921,9 @@ constructor(
                 class TieredBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -9423,12 +12932,29 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9438,13 +12964,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                            tiers = tieredBpsConfig.tiers.toMutableList()
+                            tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties =
                                 tieredBpsConfig.additionalProperties.toMutableMap()
                         }
@@ -9453,14 +12979,31 @@ constructor(
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                         * specified tiers
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -9488,7 +13031,7 @@ constructor(
                         fun build(): TieredBpsConfig =
                             TieredBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -9497,33 +13040,71 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("minimum_amount") private val minimumAmount: String,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Per-event basis point rate */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Inclusive tier starting value */
+                        fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Per-event basis point rate */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        fun _minimumAmount(): JsonField<String> = minimumAmount
 
                         /** Exclusive tier ending value */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** Per unit maximum to charge */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                minimumAmount()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -9533,10 +13114,10 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var minimumAmount: String? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var minimumAmount: JsonField<String>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -9550,31 +13131,46 @@ constructor(
                             }
 
                             /** Per-event basis point rate */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Per-event basis point rate */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
+
+                            /** Inclusive tier starting value */
+                            fun minimumAmount(minimumAmount: String) =
+                                minimumAmount(JsonField.of(minimumAmount))
 
                             /** Inclusive tier starting value */
-                            fun minimumAmount(minimumAmount: String) = apply {
+                            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                                 this.minimumAmount = minimumAmount
                             }
 
                             /** Exclusive tier ending value */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Exclusive tier ending value */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** Per unit maximum to charge */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Exclusive tier ending value */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** Per unit maximum to charge */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -9653,22 +13249,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9678,8 +13298,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9693,10 +13313,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -9817,22 +13444,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9842,8 +13493,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9858,10 +13509,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -9991,6 +13649,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10072,96 +13738,229 @@ constructor(
             class NewSubscriptionBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+                fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -10169,19 +13968,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBpsPrice = apply {
+                    if (!validated) {
+                        bpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10191,22 +14016,25 @@ constructor(
 
                 class Builder {
 
-                    private var bpsConfig: BpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bpsConfig: JsonField<BpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10233,26 +14061,42 @@ constructor(
                             newSubscriptionBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                    fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                    fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                        this.bpsConfig = bpsConfig
+                    }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -10261,13 +14105,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -10284,13 +14135,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -10300,12 +14159,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -10320,11 +14186,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -10332,22 +14205,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -10364,22 +14246,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -10389,12 +14286,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -10403,11 +14308,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -10416,6 +14329,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -10464,23 +14385,45 @@ constructor(
                 class BpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis point take rate per event */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis point take rate per event */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Optional currency amount maximum to cap spend per event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BpsConfig = apply {
+                        if (!validated) {
+                            bps()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10490,8 +14433,8 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10503,17 +14446,24 @@ constructor(
                         }
 
                         /** Basis point take rate per event */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis point take rate per event */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Optional currency amount maximum to cap spend per event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
-                        }
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                         /** Optional currency amount maximum to cap spend per event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Optional currency amount maximum to cap spend per event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -10704,22 +14654,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10729,8 +14703,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10744,10 +14718,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -10868,22 +14849,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10893,8 +14898,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10909,10 +14914,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -11042,6 +15054,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11123,96 +15143,229 @@ constructor(
             class NewSubscriptionBulkBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+                fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -11220,19 +15373,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkBpsPrice = apply {
+                    if (!validated) {
+                        bulkBpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11242,22 +15421,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkBpsConfig: BulkBpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -11285,28 +15467,43 @@ constructor(
                                 newSubscriptionBulkBpsPrice.additionalProperties.toMutableMap()
                         }
 
-                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                        bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                    fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                         this.bulkBpsConfig = bulkBpsConfig
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -11315,13 +15512,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -11338,13 +15542,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -11354,12 +15566,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -11374,11 +15593,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -11386,22 +15612,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -11418,22 +15653,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -11443,12 +15693,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -11457,11 +15715,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -11470,6 +15736,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -11520,7 +15794,9 @@ constructor(
                 class BulkBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -11529,12 +15805,29 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11544,13 +15837,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                            tiers = bulkBpsConfig.tiers.toMutableList()
+                            tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                         }
 
@@ -11558,14 +15851,31 @@ constructor(
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a bulk BPS pricing model where all usage is aggregated to a
+                         * single tier based on total volume
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -11593,7 +15903,7 @@ constructor(
                         fun build(): BulkBpsConfig =
                             BulkBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -11602,29 +15912,59 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Basis points to rate on */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Upper bound for tier */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Basis points to rate on */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Upper bound for tier */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** The maximum amount to charge for any one event */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -11634,9 +15974,9 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -11649,26 +15989,37 @@ constructor(
                             }
 
                             /** Basis points to rate on */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Basis points to rate on */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Upper bound for tier */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Upper bound for tier */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** The maximum amount to charge for any one event */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Upper bound for tier */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** The maximum amount to charge for any one event */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -11878,22 +16229,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11903,8 +16278,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -11918,10 +16293,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12042,22 +16424,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12067,8 +16473,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -12083,10 +16489,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12216,6 +16629,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12297,96 +16718,229 @@ constructor(
             class NewSubscriptionBulkPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+                fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -12394,19 +16948,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkPrice = apply {
+                    if (!validated) {
+                        bulkConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12416,22 +16996,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkConfig: BulkConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkConfig: JsonField<BulkConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -12458,26 +17041,42 @@ constructor(
                             newSubscriptionBulkPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                    fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                    fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                        this.bulkConfig = bulkConfig
+                    }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -12486,13 +17085,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -12509,13 +17115,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -12525,12 +17139,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -12545,11 +17166,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -12557,22 +17185,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -12589,22 +17226,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -12614,12 +17266,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -12628,11 +17288,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -12641,6 +17309,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -12689,18 +17365,34 @@ constructor(
                 class BulkConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Bulk tiers for rating based on total usage volume */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12710,22 +17402,36 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkConfig: BulkConfig) = apply {
-                            tiers = bulkConfig.tiers.toMutableList()
+                            tiers = bulkConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                         }
 
                         /** Bulk tiers for rating based on total usage volume */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /** Bulk tiers for rating based on total usage volume */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /** Bulk tiers for rating based on total usage volume */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -12753,7 +17459,7 @@ constructor(
                         fun build(): BulkConfig =
                             BulkConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -12762,24 +17468,48 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_units")
+                        @ExcludeMissing
+                        private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /** Upper bound for this tier */
+                        fun maximumUnits(): Optional<Double> =
+                            Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /** Upper bound for this tier */
                         @JsonProperty("maximum_units")
-                        fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                        @ExcludeMissing
+                        fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                unitAmount()
+                                maximumUnits()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -12789,8 +17519,8 @@ constructor(
 
                         class Builder {
 
-                            private var unitAmount: String? = null
-                            private var maximumUnits: Double? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var maximumUnits: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -12802,14 +17532,17 @@ constructor(
                             }
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
                             /** Upper bound for this tier */
-                            fun maximumUnits(maximumUnits: Double?) = apply {
-                                this.maximumUnits = maximumUnits
-                            }
+                            fun maximumUnits(maximumUnits: Double?) =
+                                maximumUnits(JsonField.ofNullable(maximumUnits))
 
                             /** Upper bound for this tier */
                             fun maximumUnits(maximumUnits: Double) =
@@ -12822,6 +17555,11 @@ constructor(
                             fun maximumUnits(maximumUnits: Optional<Double>) =
                                 maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                            /** Upper bound for this tier */
+                            fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                                this.maximumUnits = maximumUnits
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -13032,22 +17770,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13057,8 +17819,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13072,10 +17834,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13196,22 +17965,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13221,8 +18014,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13237,10 +18030,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13370,6 +18170,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13451,42 +18259,166 @@ constructor(
             class NewSubscriptionThresholdTotalAmountPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("threshold_total_amount_config")
-                private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("threshold_total_amount_config")
                 fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                    thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("threshold_total_amount_config")
+                @ExcludeMissing
+                fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                     thresholdTotalAmountConfig
 
                 /**
@@ -13494,56 +18426,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -13551,19 +18492,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionThresholdTotalAmountPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        thresholdTotalAmountConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13573,22 +18540,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -13623,27 +18594,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun thresholdTotalAmountConfig(
                         thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                    ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                    fun thresholdTotalAmountConfig(
+                        thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                     ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -13652,13 +18639,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -13675,13 +18669,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -13691,12 +18693,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -13711,11 +18720,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -13723,22 +18739,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -13755,22 +18780,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -13780,12 +18820,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -13794,11 +18842,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -13807,6 +18863,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -13999,6 +19063,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): ThresholdTotalAmountConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14070,22 +19142,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14095,8 +19191,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14110,10 +19206,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14234,22 +19337,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14259,8 +19386,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14275,10 +19402,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14408,6 +19542,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14489,98 +19631,230 @@ constructor(
             class NewSubscriptionTieredPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_package_config")
-                private val tieredPackageConfig: TieredPackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageConfig(): TieredPackageConfig =
+                    tieredPackageConfig.getRequired("tiered_package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_config")
-                fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+                @ExcludeMissing
+                fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -14588,19 +19862,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14610,22 +19910,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageConfig: TieredPackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -14655,27 +19958,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                        this.tieredPackageConfig = tieredPackageConfig
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
                     }
 
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                        tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                    fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                        apply {
+                            this.tieredPackageConfig = tieredPackageConfig
+                        }
+
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -14684,13 +20003,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -14707,13 +20033,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -14723,12 +20057,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -14743,11 +20084,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -14755,22 +20103,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -14787,22 +20144,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -14812,12 +20184,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -14826,11 +20206,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -14839,6 +20227,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -15031,6 +20427,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15101,22 +20505,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15126,8 +20554,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15141,10 +20569,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15265,22 +20700,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15290,8 +20749,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15306,10 +20765,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15439,6 +20905,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15520,98 +20994,232 @@ constructor(
             class NewSubscriptionTieredWithMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_minimum_config")
-                private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                    tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_minimum_config")
-                fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+                @ExcludeMissing
+                fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                    tieredWithMinimumConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -15619,19 +21227,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15641,22 +21275,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -15690,28 +21327,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                        apply {
-                            this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                        }
+                        tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                    fun tieredWithMinimumConfig(
+                        tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                    ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -15720,13 +21371,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -15743,13 +21401,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -15759,12 +21425,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -15779,11 +21452,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -15791,22 +21471,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -15823,22 +21512,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -15848,12 +21552,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -15862,11 +21574,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -15875,6 +21595,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -16067,6 +21795,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16138,22 +21874,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16163,8 +21923,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16178,10 +21938,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16302,22 +22069,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16327,8 +22118,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16343,10 +22134,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16476,6 +22274,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16557,98 +22363,232 @@ constructor(
             class NewSubscriptionUnitWithPercentPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_percent_config")
-                private val unitWithPercentConfig: UnitWithPercentConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithPercentConfig(): UnitWithPercentConfig =
+                    unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_percent_config")
-                fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+                @ExcludeMissing
+                fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> =
+                    unitWithPercentConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -16656,19 +22596,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithPercentPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithPercentConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16678,22 +22644,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -16724,28 +22693,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
-                        apply {
-                            this.unitWithPercentConfig = unitWithPercentConfig
-                        }
+                        unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                    fun unitWithPercentConfig(
+                        unitWithPercentConfig: JsonField<UnitWithPercentConfig>
+                    ) = apply { this.unitWithPercentConfig = unitWithPercentConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -16754,13 +22737,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -16777,13 +22767,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -16793,12 +22791,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -16813,11 +22818,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -16825,22 +22837,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -16857,22 +22878,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -16882,12 +22918,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -16896,11 +22940,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -16909,6 +22961,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -17101,6 +23161,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithPercentConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17171,22 +23239,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17196,8 +23288,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17211,10 +23303,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17335,22 +23434,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17360,8 +23483,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17376,10 +23499,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17509,6 +23639,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17590,42 +23728,166 @@ constructor(
             class NewSubscriptionPackageWithAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("package_with_allocation_config")
-                private val packageWithAllocationConfig: PackageWithAllocationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("package_with_allocation_config")
                 fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                    packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("package_with_allocation_config")
+                @ExcludeMissing
+                fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                     packageWithAllocationConfig
 
                 /**
@@ -17633,56 +23895,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -17690,19 +23961,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackageWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageWithAllocationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17712,22 +24009,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageWithAllocationConfig:
+                        JsonField<PackageWithAllocationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -17763,27 +24065,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun packageWithAllocationConfig(
                         packageWithAllocationConfig: PackageWithAllocationConfig
+                    ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                    fun packageWithAllocationConfig(
+                        packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                     ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -17792,13 +24110,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -17815,13 +24140,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -17831,12 +24164,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -17851,11 +24191,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -17863,22 +24210,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -17895,22 +24251,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -17920,12 +24291,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -17934,11 +24313,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -17947,6 +24334,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -18139,6 +24534,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageWithAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18211,22 +24614,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18236,8 +24663,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18251,10 +24678,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18375,22 +24809,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18400,8 +24858,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18416,10 +24874,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18549,6 +25014,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18630,42 +25103,166 @@ constructor(
             class NewSubscriptionTierWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_proration_config")
-                private val tieredWithProrationConfig: TieredWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_with_proration_config")
                 fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                    tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_with_proration_config")
+                @ExcludeMissing
+                fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
                     tieredWithProrationConfig
 
                 /**
@@ -18673,56 +25270,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -18730,19 +25336,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTierWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18752,22 +25384,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -18801,27 +25437,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithProrationConfig(
                         tieredWithProrationConfig: TieredWithProrationConfig
+                    ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                    fun tieredWithProrationConfig(
+                        tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                     ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -18830,13 +25482,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -18853,13 +25512,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -18869,12 +25536,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -18889,11 +25563,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -18901,22 +25582,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -18933,22 +25623,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -18958,12 +25663,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -18972,11 +25685,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -18985,6 +25706,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -19177,6 +25906,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19248,22 +25985,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19273,8 +26034,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19288,10 +26049,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19412,22 +26180,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19437,8 +26229,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19453,10 +26245,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19586,6 +26385,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19667,98 +26474,232 @@ constructor(
             class NewSubscriptionUnitWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_proration_config")
-                private val unitWithProrationConfig: UnitWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithProrationConfig(): UnitWithProrationConfig =
+                    unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_proration_config")
-                fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+                @ExcludeMissing
+                fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                    unitWithProrationConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -19766,19 +26707,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19788,22 +26755,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -19837,28 +26807,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                        apply {
-                            this.unitWithProrationConfig = unitWithProrationConfig
-                        }
+                        unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                    fun unitWithProrationConfig(
+                        unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                    ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -19867,13 +26851,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -19890,13 +26881,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -19906,12 +26905,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -19926,11 +26932,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -19938,22 +26951,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -19970,22 +26992,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -19995,12 +27032,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -20009,11 +27054,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -20022,6 +27075,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -20214,6 +27275,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20285,22 +27354,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20310,8 +27403,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20325,10 +27418,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20449,22 +27549,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20474,8 +27598,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20490,10 +27614,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20623,6 +27754,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20704,98 +27843,232 @@ constructor(
             class NewSubscriptionGroupedAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_allocation_config")
-                private val groupedAllocationConfig: GroupedAllocationConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                fun groupedAllocationConfig(): GroupedAllocationConfig =
+                    groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 @JsonProperty("grouped_allocation_config")
-                fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+                @ExcludeMissing
+                fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                    groupedAllocationConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -20803,19 +28076,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedAllocationConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20825,22 +28124,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -20874,28 +28176,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                        apply {
-                            this.groupedAllocationConfig = groupedAllocationConfig
-                        }
+                        groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                    fun groupedAllocationConfig(
+                        groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                    ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -20904,13 +28220,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -20927,13 +28250,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -20943,12 +28274,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -20963,11 +28301,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -20975,22 +28320,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -21007,22 +28361,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -21032,12 +28401,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -21046,11 +28423,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -21059,6 +28444,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -21199,6 +28592,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21322,22 +28723,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21347,8 +28772,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21362,10 +28787,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21486,22 +28918,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21511,8 +28967,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21527,10 +28983,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21660,6 +29123,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21741,99 +29212,235 @@ constructor(
             class NewSubscriptionGroupedWithProratedMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_with_prorated_minimum_config")
-                private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
-                @JsonProperty("grouped_with_prorated_minimum_config")
                 fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
-                    groupedWithProratedMinimumConfig
+                    groupedWithProratedMinimumConfig.getRequired(
+                        "grouped_with_prorated_minimum_config"
+                    )
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                @JsonProperty("grouped_with_prorated_minimum_config")
+                @ExcludeMissing
+                fun _groupedWithProratedMinimumConfig():
+                    JsonField<GroupedWithProratedMinimumConfig> = groupedWithProratedMinimumConfig
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -21841,19 +29448,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedWithProratedMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedWithProratedMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21863,24 +29496,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
+                    private var cadence: JsonField<Cadence>? = null
                     private var groupedWithProratedMinimumConfig:
-                        GroupedWithProratedMinimumConfig? =
+                        JsonField<GroupedWithProratedMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -21921,29 +29557,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedWithProratedMinimumConfig(
                         groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                    ) =
+                        groupedWithProratedMinimumConfig(
+                            JsonField.of(groupedWithProratedMinimumConfig)
+                        )
+
+                    fun groupedWithProratedMinimumConfig(
+                        groupedWithProratedMinimumConfig:
+                            JsonField<GroupedWithProratedMinimumConfig>
                     ) = apply {
                         this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -21952,13 +29608,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -21975,13 +29638,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -21991,12 +29662,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -22011,11 +29689,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -22023,22 +29708,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -22055,22 +29749,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -22080,12 +29789,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -22094,11 +29811,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -22107,6 +29832,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -22247,6 +29980,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithProratedMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22372,22 +30113,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22397,8 +30162,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22412,10 +30177,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22536,22 +30308,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22561,8 +30357,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22577,10 +30373,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22710,6 +30513,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22792,97 +30603,231 @@ constructor(
             @JsonCreator
             private constructor(
                 @JsonProperty("bulk_with_proration_config")
-                private val bulkWithProrationConfig: BulkWithProrationConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                    bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
                 @JsonProperty("bulk_with_proration_config")
-                fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+                @ExcludeMissing
+                fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                    bulkWithProrationConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -22890,19 +30835,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkWithProrationPrice = apply {
+                    if (!validated) {
+                        bulkWithProrationConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22912,22 +30883,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -22961,28 +30935,42 @@ constructor(
                     }
 
                     fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                        apply {
-                            this.bulkWithProrationConfig = bulkWithProrationConfig
-                        }
+                        bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                    fun bulkWithProrationConfig(
+                        bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                    ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -22991,13 +30979,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -23014,13 +31009,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -23030,12 +31033,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -23050,11 +31060,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -23062,22 +31079,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -23094,22 +31120,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -23119,12 +31160,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -23133,11 +31182,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -23146,6 +31203,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -23204,6 +31269,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23409,22 +31482,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23434,8 +31531,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23449,10 +31546,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23573,22 +31677,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23598,8 +31726,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23614,10 +31742,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23747,6 +31882,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23847,9 +31990,11 @@ constructor(
     class BillingCycleAnchorConfiguration
     @JsonCreator
     private constructor(
-        @JsonProperty("day") private val day: Long,
-        @JsonProperty("month") private val month: Long?,
-        @JsonProperty("year") private val year: Long?,
+        @JsonProperty("day") @ExcludeMissing private val day: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("month")
+        @ExcludeMissing
+        private val month: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("year") @ExcludeMissing private val year: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -23860,24 +32005,55 @@ constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") fun day(): Long = day
+        fun day(): Long = day.getRequired("day")
+
+        /**
+         * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+         * February would have cycles starting February, May, August, and November).
+         */
+        fun month(): Optional<Long> = Optional.ofNullable(month.getNullable("month"))
+
+        /**
+         * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
+         * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+         */
+        fun year(): Optional<Long> = Optional.ofNullable(year.getNullable("year"))
+
+        /**
+         * The day of the month on which the billing cycle is anchored. If the maximum number of
+         * days in a month is greater than this value, the last day of the month is the billing
+         * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
+         * 30th.
+         */
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") fun month(): Optional<Long> = Optional.ofNullable(month)
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") fun year(): Optional<Long> = Optional.ofNullable(year)
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): BillingCycleAnchorConfiguration = apply {
+            if (!validated) {
+                day()
+                month()
+                year()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -23887,9 +32063,9 @@ constructor(
 
         class Builder {
 
-            private var day: Long? = null
-            private var month: Long? = null
-            private var year: Long? = null
+            private var day: JsonField<Long>? = null
+            private var month: JsonField<Long> = JsonMissing.of()
+            private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -23908,13 +32084,21 @@ constructor(
              * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
              * 30th.
              */
-            fun day(day: Long) = apply { this.day = day }
+            fun day(day: Long) = day(JsonField.of(day))
+
+            /**
+             * The day of the month on which the billing cycle is anchored. If the maximum number of
+             * days in a month is greater than this value, the last day of the month is the billing
+             * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
+             * 30th.
+             */
+            fun day(day: JsonField<Long>) = apply { this.day = day }
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long?) = apply { this.month = month }
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -23929,11 +32113,17 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: JsonField<Long>) = apply { this.month = month }
+
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long?) = apply { this.year = year }
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -23948,6 +32138,12 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: JsonField<Long>) = apply { this.year = year }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -24074,6 +32270,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24133,18 +32337,34 @@ constructor(
     class RemoveAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment_id") private val adjustmentId: String,
+        @JsonProperty("adjustment_id")
+        @ExcludeMissing
+        private val adjustmentId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The id of the adjustment to remove on the subscription. */
-        @JsonProperty("adjustment_id") fun adjustmentId(): String = adjustmentId
+        fun adjustmentId(): String = adjustmentId.getRequired("adjustment_id")
+
+        /** The id of the adjustment to remove on the subscription. */
+        @JsonProperty("adjustment_id")
+        @ExcludeMissing
+        fun _adjustmentId(): JsonField<String> = adjustmentId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): RemoveAdjustment = apply {
+            if (!validated) {
+                adjustmentId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24154,7 +32374,7 @@ constructor(
 
         class Builder {
 
-            private var adjustmentId: String? = null
+            private var adjustmentId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24164,7 +32384,12 @@ constructor(
             }
 
             /** The id of the adjustment to remove on the subscription. */
-            fun adjustmentId(adjustmentId: String) = apply { this.adjustmentId = adjustmentId }
+            fun adjustmentId(adjustmentId: String) = adjustmentId(JsonField.of(adjustmentId))
+
+            /** The id of the adjustment to remove on the subscription. */
+            fun adjustmentId(adjustmentId: JsonField<String>) = apply {
+                this.adjustmentId = adjustmentId
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -24214,23 +32439,45 @@ constructor(
     class RemovePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("price_id") private val priceId: String?,
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /** The external price id of the price to remove on the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** The id of the price to remove on the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
         /** The external price id of the price to remove on the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** The id of the price to remove on the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): RemovePrice = apply {
+            if (!validated) {
+                externalPriceId()
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24240,8 +32487,8 @@ constructor(
 
         class Builder {
 
-            private var externalPriceId: String? = null
-            private var priceId: String? = null
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24252,20 +32499,27 @@ constructor(
             }
 
             /** The external price id of the price to remove on the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to remove on the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** The external price id of the price to remove on the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /** The id of the price to remove on the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to remove on the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to remove on the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -24315,23 +32569,47 @@ constructor(
     class ReplaceAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment") private val adjustment: Adjustment,
-        @JsonProperty("replaces_adjustment_id") private val replacesAdjustmentId: String,
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        private val adjustment: JsonField<Adjustment> = JsonMissing.of(),
+        @JsonProperty("replaces_adjustment_id")
+        @ExcludeMissing
+        private val replacesAdjustmentId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The definition of a new adjustment to create and add to the subscription. */
-        @JsonProperty("adjustment") fun adjustment(): Adjustment = adjustment
+        fun adjustment(): Adjustment = adjustment.getRequired("adjustment")
+
+        /** The id of the adjustment on the plan to replace in the subscription. */
+        fun replacesAdjustmentId(): String =
+            replacesAdjustmentId.getRequired("replaces_adjustment_id")
+
+        /** The definition of a new adjustment to create and add to the subscription. */
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The id of the adjustment on the plan to replace in the subscription. */
         @JsonProperty("replaces_adjustment_id")
-        fun replacesAdjustmentId(): String = replacesAdjustmentId
+        @ExcludeMissing
+        fun _replacesAdjustmentId(): JsonField<String> = replacesAdjustmentId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReplaceAdjustment = apply {
+            if (!validated) {
+                adjustment()
+                replacesAdjustmentId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24341,8 +32619,8 @@ constructor(
 
         class Builder {
 
-            private var adjustment: Adjustment? = null
-            private var replacesAdjustmentId: String? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var replacesAdjustmentId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24353,30 +32631,34 @@ constructor(
             }
 
             /** The definition of a new adjustment to create and add to the subscription. */
-            fun adjustment(adjustment: Adjustment) = apply { this.adjustment = adjustment }
+            fun adjustment(adjustment: Adjustment) = adjustment(JsonField.of(adjustment))
 
-            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewPercentageDiscount(newPercentageDiscount)
+            /** The definition of a new adjustment to create and add to the subscription. */
+            fun adjustment(adjustment: JsonField<Adjustment>) = apply {
+                this.adjustment = adjustment
             }
 
-            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewUsageDiscount(newUsageDiscount)
-            }
+            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) =
+                adjustment(Adjustment.ofNewPercentageDiscount(newPercentageDiscount))
 
-            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) = apply {
-                this.adjustment = Adjustment.ofNewAmountDiscount(newAmountDiscount)
-            }
+            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) =
+                adjustment(Adjustment.ofNewUsageDiscount(newUsageDiscount))
 
-            fun adjustment(newMinimum: Adjustment.NewMinimum) = apply {
-                this.adjustment = Adjustment.ofNewMinimum(newMinimum)
-            }
+            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) =
+                adjustment(Adjustment.ofNewAmountDiscount(newAmountDiscount))
 
-            fun adjustment(newMaximum: Adjustment.NewMaximum) = apply {
-                this.adjustment = Adjustment.ofNewMaximum(newMaximum)
-            }
+            fun adjustment(newMinimum: Adjustment.NewMinimum) =
+                adjustment(Adjustment.ofNewMinimum(newMinimum))
+
+            fun adjustment(newMaximum: Adjustment.NewMaximum) =
+                adjustment(Adjustment.ofNewMaximum(newMaximum))
+
+            /** The id of the adjustment on the plan to replace in the subscription. */
+            fun replacesAdjustmentId(replacesAdjustmentId: String) =
+                replacesAdjustmentId(JsonField.of(replacesAdjustmentId))
 
             /** The id of the adjustment on the plan to replace in the subscription. */
-            fun replacesAdjustmentId(replacesAdjustmentId: String) = apply {
+            fun replacesAdjustmentId(replacesAdjustmentId: JsonField<String>) = apply {
                 this.replacesAdjustmentId = replacesAdjustmentId
             }
 
@@ -24422,6 +32704,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newPercentageDiscount(): Optional<NewPercentageDiscount> =
                 Optional.ofNullable(newPercentageDiscount)
 
@@ -24472,6 +32756,26 @@ constructor(
                 }
             }
 
+            fun validate(): Adjustment = apply {
+                if (!validated) {
+                    if (
+                        newPercentageDiscount == null &&
+                            newUsageDiscount == null &&
+                            newAmountDiscount == null &&
+                            newMinimum == null &&
+                            newMaximum == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Adjustment: $_json")
+                    }
+                    newPercentageDiscount?.validate()
+                    newUsageDiscount?.validate()
+                    newAmountDiscount?.validate()
+                    newMinimum?.validate()
+                    newMaximum?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -24541,29 +32845,40 @@ constructor(
 
                     when (adjustmentType) {
                         "percentage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>())?.let {
-                                return Adjustment(newPercentageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newPercentageDiscount = it, _json = json)
+                                }
                         }
                         "usage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>())?.let {
-                                return Adjustment(newUsageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newUsageDiscount = it, _json = json)
+                                }
                         }
                         "amount_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>())?.let {
-                                return Adjustment(newAmountDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newAmountDiscount = it, _json = json)
+                                }
                         }
                         "minimum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMinimum>())?.let {
-                                return Adjustment(newMinimum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMinimum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMinimum = it, _json = json)
+                                }
                         }
                         "maximum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMaximum>())?.let {
-                                return Adjustment(newMaximum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMaximum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMaximum = it, _json = json)
+                                }
                         }
                     }
 
@@ -24597,35 +32912,75 @@ constructor(
             class NewPercentageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewPercentageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        percentageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -24635,47 +32990,58 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var percentageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newPercentageDiscount: NewPercentageDiscount) = apply {
                         adjustmentType = newPercentageDiscount.adjustmentType
-                        appliesToPriceIds = newPercentageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newPercentageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         percentageDiscount = newPercentageDiscount.percentageDiscount
                         isInvoiceLevel = newPercentageDiscount.isInvoiceLevel
                         additionalProperties =
                             newPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
-                        this.percentageDiscount = percentageDiscount
-                    }
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                        this.percentageDiscount = percentageDiscount
                     }
 
                     /**
@@ -24683,15 +33049,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -24723,7 +33089,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(percentageDiscount) {
                                 "`percentageDiscount` is required but was not set"
                             },
@@ -24806,34 +33172,74 @@ constructor(
             class NewUsageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewUsageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        usageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -24843,46 +33249,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var usageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var usageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newUsageDiscount: NewUsageDiscount) = apply {
                         adjustmentType = newUsageDiscount.adjustmentType
-                        appliesToPriceIds = newUsageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newUsageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         usageDiscount = newUsageDiscount.usageDiscount
                         isInvoiceLevel = newUsageDiscount.isInvoiceLevel
                         additionalProperties = newUsageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun usageDiscount(usageDiscount: Double) = apply {
-                        this.usageDiscount = usageDiscount
-                    }
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                        this.usageDiscount = usageDiscount
                     }
 
                     /**
@@ -24890,15 +33307,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -24930,7 +33347,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(usageDiscount) {
                                 "`usageDiscount` is required but was not set"
                             },
@@ -25013,34 +33430,74 @@ constructor(
             class NewAmountDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("amount_discount") private val amountDiscount: String,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
-                @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewAmountDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        amountDiscount()
+                        appliesToPriceIds()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25050,46 +33507,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var amountDiscount: String? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newAmountDiscount: NewAmountDiscount) = apply {
                         adjustmentType = newAmountDiscount.adjustmentType
                         amountDiscount = newAmountDiscount.amountDiscount
-                        appliesToPriceIds = newAmountDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newAmountDiscount.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = newAmountDiscount.isInvoiceLevel
                         additionalProperties = newAmountDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
-                    fun amountDiscount(amountDiscount: String) = apply {
+                    fun amountDiscount(amountDiscount: String) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
-                    }
-
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -25097,15 +33565,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25140,7 +33608,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             isInvoiceLevel,
                             additionalProperties.toImmutable(),
                         )
@@ -25220,38 +33688,84 @@ constructor(
             class NewMinimum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /** The item ID that revenue from this minimum will be attributed to. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMinimum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        itemId()
+                        minimumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25261,51 +33775,64 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var itemId: String? = null
-                    private var minimumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMinimum: NewMinimum) = apply {
                         adjustmentType = newMinimum.adjustmentType
-                        appliesToPriceIds = newMinimum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMinimum.appliesToPriceIds.map { it.toMutableList() }
                         itemId = newMinimum.itemId
                         minimumAmount = newMinimum.minimumAmount
                         isInvoiceLevel = newMinimum.isInvoiceLevel
                         additionalProperties = newMinimum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /** The item ID that revenue from this minimum will be attributed to. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun minimumAmount(minimumAmount: String) = apply {
-                        this.minimumAmount = minimumAmount
-                    }
+                    /** The item ID that revenue from this minimum will be attributed to. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                        this.minimumAmount = minimumAmount
                     }
 
                     /**
@@ -25313,15 +33840,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25353,7 +33880,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(itemId) { "`itemId` is required but was not set" },
                             checkNotNull(minimumAmount) {
                                 "`minimumAmount` is required but was not set"
@@ -25437,34 +33964,74 @@ constructor(
             class NewMaximum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("maximum_amount") private val maximumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun maximumAmount(): String = maximumAmount.getRequired("maximum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("maximum_amount") fun maximumAmount(): String = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMaximum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        maximumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25474,46 +34041,56 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var maximumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMaximum: NewMaximum) = apply {
                         adjustmentType = newMaximum.adjustmentType
-                        appliesToPriceIds = newMaximum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMaximum.appliesToPriceIds.map { it.toMutableList() }
                         maximumAmount = newMaximum.maximumAmount
                         isInvoiceLevel = newMaximum.isInvoiceLevel
                         additionalProperties = newMaximum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun maximumAmount(maximumAmount: String) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String) =
+                        maximumAmount(JsonField.of(maximumAmount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
                     /**
@@ -25521,15 +34098,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25561,7 +34138,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(maximumAmount) {
                                 "`maximumAmount` is required but was not set"
                             },
@@ -25663,60 +34240,137 @@ constructor(
     class ReplacePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("replaces_price_id") private val replacesPriceId: String,
-        @JsonProperty("discounts") private val discounts: List<Discount>?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-        @JsonProperty("minimum_amount") private val minimumAmount: String?,
-        @JsonProperty("price") private val price: Price?,
-        @JsonProperty("price_id") private val priceId: String?,
+        @JsonProperty("replaces_price_id")
+        @ExcludeMissing
+        private val replacesPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        private val discounts: JsonField<List<Discount>> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("price")
+        @ExcludeMissing
+        private val price: JsonField<Price> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The id of the price on the plan to replace in the subscription. */
-        @JsonProperty("replaces_price_id") fun replacesPriceId(): String = replacesPriceId
+        fun replacesPriceId(): String = replacesPriceId.getRequired("replaces_price_id")
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
+         * replacement price.
+         */
+        fun discounts(): Optional<List<Discount>> =
+            Optional.ofNullable(discounts.getNullable("discounts"))
+
+        /** The external price id of the price to add to the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** The new quantity of the price, if the price is a fixed price. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
+         * replacement price.
+         */
+        fun maximumAmount(): Optional<String> =
+            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
+         * replacement price.
+         */
+        fun minimumAmount(): Optional<String> =
+            Optional.ofNullable(minimumAmount.getNullable("minimum_amount"))
+
+        /** The definition of a new price to create and add to the subscription. */
+        fun price(): Optional<Price> = Optional.ofNullable(price.getNullable("price"))
+
+        /** The id of the price to add to the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
+        /** The id of the price on the plan to replace in the subscription. */
+        @JsonProperty("replaces_price_id")
+        @ExcludeMissing
+        fun _replacesPriceId(): JsonField<String> = replacesPriceId
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
          * replacement price.
          */
         @JsonProperty("discounts")
-        fun discounts(): Optional<List<Discount>> = Optional.ofNullable(discounts)
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         /** The external price id of the price to add to the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** The new quantity of the price, if the price is a fixed price. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
          * replacement price.
          */
         @JsonProperty("maximum_amount")
-        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
          * replacement price.
          */
         @JsonProperty("minimum_amount")
-        fun minimumAmount(): Optional<String> = Optional.ofNullable(minimumAmount)
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The definition of a new price to create and add to the subscription. */
-        @JsonProperty("price") fun price(): Optional<Price> = Optional.ofNullable(price)
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /** The id of the price to add to the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReplacePrice = apply {
+            if (!validated) {
+                replacesPriceId()
+                discounts().map { it.forEach { it.validate() } }
+                externalPriceId()
+                fixedPriceQuantity()
+                maximumAmount()
+                minimumAmount()
+                price()
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -25726,20 +34380,20 @@ constructor(
 
         class Builder {
 
-            private var replacesPriceId: String? = null
-            private var discounts: MutableList<Discount>? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var maximumAmount: String? = null
-            private var minimumAmount: String? = null
-            private var price: Price? = null
-            private var priceId: String? = null
+            private var replacesPriceId: JsonField<String>? = null
+            private var discounts: JsonField<MutableList<Discount>>? = null
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var price: JsonField<Price> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(replacePrice: ReplacePrice) = apply {
                 replacesPriceId = replacePrice.replacesPriceId
-                discounts = replacePrice.discounts?.toMutableList()
+                discounts = replacePrice.discounts.map { it.toMutableList() }
                 externalPriceId = replacePrice.externalPriceId
                 fixedPriceQuantity = replacePrice.fixedPriceQuantity
                 maximumAmount = replacePrice.maximumAmount
@@ -25750,7 +34404,11 @@ constructor(
             }
 
             /** The id of the price on the plan to replace in the subscription. */
-            fun replacesPriceId(replacesPriceId: String) = apply {
+            fun replacesPriceId(replacesPriceId: String) =
+                replacesPriceId(JsonField.of(replacesPriceId))
+
+            /** The id of the price on the plan to replace in the subscription. */
+            fun replacesPriceId(replacesPriceId: JsonField<String>) = apply {
                 this.replacesPriceId = replacesPriceId
             }
 
@@ -25758,9 +34416,7 @@ constructor(
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
              * replacement price.
              */
-            fun discounts(discounts: List<Discount>?) = apply {
-                this.discounts = discounts?.toMutableList()
-            }
+            fun discounts(discounts: List<Discount>?) = discounts(JsonField.ofNullable(discounts))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
@@ -25768,28 +34424,48 @@ constructor(
              */
             fun discounts(discounts: Optional<List<Discount>>) = discounts(discounts.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
+             * replacement price.
+             */
+            fun discounts(discounts: JsonField<List<Discount>>) = apply {
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
              * replacement price.
              */
             fun addDiscount(discount: Discount) = apply {
-                discounts = (discounts ?: mutableListOf()).apply { add(discount) }
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             /** The external price id of the price to add to the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to add to the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
-            /** The new quantity of the price, if the price is a fixed price. */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
+            /** The external price id of the price to add to the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
             }
 
+            /** The new quantity of the price, if the price is a fixed price. */
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             /** The new quantity of the price, if the price is a fixed price. */
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
                 fixedPriceQuantity(fixedPriceQuantity as Double?)
@@ -25799,11 +34475,17 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
+            /** The new quantity of the price, if the price is a fixed price. */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
              * replacement price.
              */
-            fun maximumAmount(maximumAmount: String?) = apply { this.maximumAmount = maximumAmount }
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
@@ -25812,11 +34494,20 @@ constructor(
             fun maximumAmount(maximumAmount: Optional<String>) =
                 maximumAmount(maximumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
+             * replacement price.
+             */
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
              * replacement price.
              */
-            fun minimumAmount(minimumAmount: String?) = apply { this.minimumAmount = minimumAmount }
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
@@ -25825,138 +34516,141 @@ constructor(
             fun minimumAmount(minimumAmount: Optional<String>) =
                 minimumAmount(minimumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
+             * replacement price.
+             */
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
+            }
+
             /** The definition of a new price to create and add to the subscription. */
-            fun price(price: Price?) = apply { this.price = price }
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /** The definition of a new price to create and add to the subscription. */
             fun price(price: Optional<Price>) = price(price.orElse(null))
 
-            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) = apply {
-                this.price = Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice)
-            }
+            /** The definition of a new price to create and add to the subscription. */
+            fun price(price: JsonField<Price>) = apply { this.price = price }
 
-            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) = apply {
-                this.price = Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice)
-            }
+            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) =
+                price(Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice))
 
-            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) = apply {
-                this.price = Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice)
-            }
+            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) =
+                price(Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice))
 
-            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice)
-            }
+            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) =
+                price(Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice))
 
-            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice)
-            }
+            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) =
+                price(Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice))
 
-            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice)
-            }
+            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) =
+                price(Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice))
 
-            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice)
-            }
+            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) =
+                price(Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice))
 
-            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice)
-            }
+            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) =
+                price(Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice))
+
+            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) =
+                price(Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice))
 
             fun price(
                 newSubscriptionThresholdTotalAmountPrice:
                     Price.NewSubscriptionThresholdTotalAmountPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionThresholdTotalAmountPrice(
                         newSubscriptionThresholdTotalAmountPrice
                     )
-            }
+                )
 
             fun price(newSubscriptionTieredPackagePrice: Price.NewSubscriptionTieredPackagePrice) =
-                apply {
-                    this.price =
-                        Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice)
-                }
+                price(Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice))
 
             fun price(
                 newSubscriptionTieredWithMinimumPrice: Price.NewSubscriptionTieredWithMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTieredWithMinimumPrice(
                         newSubscriptionTieredWithMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithPercentPrice: Price.NewSubscriptionUnitWithPercentPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithPercentPrice(newSubscriptionUnitWithPercentPrice)
-            }
+                )
 
             fun price(
                 newSubscriptionPackageWithAllocationPrice:
                     Price.NewSubscriptionPackageWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionPackageWithAllocationPrice(
                         newSubscriptionPackageWithAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionTierWithProrationPrice: Price.NewSubscriptionTierWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTierWithProrationPrice(
                         newSubscriptionTierWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithProrationPrice: Price.NewSubscriptionUnitWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithProrationPrice(
                         newSubscriptionUnitWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedAllocationPrice: Price.NewSubscriptionGroupedAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedAllocationPrice(
                         newSubscriptionGroupedAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedWithProratedMinimumPrice:
                     Price.NewSubscriptionGroupedWithProratedMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedWithProratedMinimumPrice(
                         newSubscriptionGroupedWithProratedMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionBulkWithProrationPrice: Price.NewSubscriptionBulkWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionBulkWithProrationPrice(
                         newSubscriptionBulkWithProrationPrice
                     )
-            }
+                )
 
             /** The id of the price to add to the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to add to the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to add to the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -25981,7 +34675,7 @@ constructor(
                     checkNotNull(replacesPriceId) {
                         "`replacesPriceId` is required but was not set"
                     },
-                    discounts?.toImmutable(),
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     externalPriceId,
                     fixedPriceQuantity,
                     maximumAmount,
@@ -25996,37 +34690,81 @@ constructor(
         class Discount
         @JsonCreator
         private constructor(
-            @JsonProperty("discount_type") private val discountType: DiscountType,
-            @JsonProperty("amount_discount") private val amountDiscount: String?,
-            @JsonProperty("percentage_discount") private val percentageDiscount: Double?,
-            @JsonProperty("usage_discount") private val usageDiscount: Double?,
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            private val amountDiscount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("percentage_discount")
+            @ExcludeMissing
+            private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            private val usageDiscount: JsonField<Double> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+            /** Only available if discount_type is `amount`. */
+            fun amountDiscount(): Optional<String> =
+                Optional.ofNullable(amountDiscount.getNullable("amount_discount"))
+
+            /**
+             * Only available if discount_type is `percentage`. This is a number between 0 and 1.
+             */
+            fun percentageDiscount(): Optional<Double> =
+                Optional.ofNullable(percentageDiscount.getNullable("percentage_discount"))
+
+            /**
+             * Only available if discount_type is `usage`. Number of usage units that this discount
+             * is for
+             */
+            fun usageDiscount(): Optional<Double> =
+                Optional.ofNullable(usageDiscount.getNullable("usage_discount"))
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** Only available if discount_type is `amount`. */
             @JsonProperty("amount_discount")
-            fun amountDiscount(): Optional<String> = Optional.ofNullable(amountDiscount)
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /**
              * Only available if discount_type is `percentage`. This is a number between 0 and 1.
              */
             @JsonProperty("percentage_discount")
-            fun percentageDiscount(): Optional<Double> = Optional.ofNullable(percentageDiscount)
+            @ExcludeMissing
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
             @JsonProperty("usage_discount")
-            fun usageDiscount(): Optional<Double> = Optional.ofNullable(usageDiscount)
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Discount = apply {
+                if (!validated) {
+                    discountType()
+                    amountDiscount()
+                    percentageDiscount()
+                    usageDiscount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -26036,10 +34774,10 @@ constructor(
 
             class Builder {
 
-                private var discountType: DiscountType? = null
-                private var amountDiscount: String? = null
-                private var percentageDiscount: Double? = null
-                private var usageDiscount: Double? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var amountDiscount: JsonField<String> = JsonMissing.of()
+                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+                private var usageDiscount: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26051,26 +34789,32 @@ constructor(
                     additionalProperties = discount.additionalProperties.toMutableMap()
                 }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
                 /** Only available if discount_type is `amount`. */
-                fun amountDiscount(amountDiscount: String?) = apply {
-                    this.amountDiscount = amountDiscount
-                }
+                fun amountDiscount(amountDiscount: String?) =
+                    amountDiscount(JsonField.ofNullable(amountDiscount))
 
                 /** Only available if discount_type is `amount`. */
                 fun amountDiscount(amountDiscount: Optional<String>) =
                     amountDiscount(amountDiscount.orElse(null))
 
+                /** Only available if discount_type is `amount`. */
+                fun amountDiscount(amountDiscount: JsonField<String>) = apply {
+                    this.amountDiscount = amountDiscount
+                }
+
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
                  * and 1.
                  */
-                fun percentageDiscount(percentageDiscount: Double?) = apply {
-                    this.percentageDiscount = percentageDiscount
-                }
+                fun percentageDiscount(percentageDiscount: Double?) =
+                    percentageDiscount(JsonField.ofNullable(percentageDiscount))
 
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
@@ -26087,13 +34831,20 @@ constructor(
                 fun percentageDiscount(percentageDiscount: Optional<Double>) =
                     percentageDiscount(percentageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `percentage`. This is a number between 0
+                 * and 1.
+                 */
+                fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                    this.percentageDiscount = percentageDiscount
+                }
+
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
                  * discount is for
                  */
-                fun usageDiscount(usageDiscount: Double?) = apply {
-                    this.usageDiscount = usageDiscount
-                }
+                fun usageDiscount(usageDiscount: Double?) =
+                    usageDiscount(JsonField.ofNullable(usageDiscount))
 
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
@@ -26109,6 +34860,14 @@ constructor(
                 fun usageDiscount(usageDiscount: Optional<Double>) =
                     usageDiscount(usageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `usage`. Number of usage units that this
+                 * discount is for
+                 */
+                fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                    this.usageDiscount = usageDiscount
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -26266,6 +35025,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newSubscriptionUnitPrice(): Optional<NewSubscriptionUnitPrice> =
                 Optional.ofNullable(newSubscriptionUnitPrice)
 
@@ -26514,6 +35275,52 @@ constructor(
                 }
             }
 
+            fun validate(): Price = apply {
+                if (!validated) {
+                    if (
+                        newSubscriptionUnitPrice == null &&
+                            newSubscriptionPackagePrice == null &&
+                            newSubscriptionMatrixPrice == null &&
+                            newSubscriptionTieredPrice == null &&
+                            newSubscriptionTieredBpsPrice == null &&
+                            newSubscriptionBpsPrice == null &&
+                            newSubscriptionBulkBpsPrice == null &&
+                            newSubscriptionBulkPrice == null &&
+                            newSubscriptionThresholdTotalAmountPrice == null &&
+                            newSubscriptionTieredPackagePrice == null &&
+                            newSubscriptionTieredWithMinimumPrice == null &&
+                            newSubscriptionUnitWithPercentPrice == null &&
+                            newSubscriptionPackageWithAllocationPrice == null &&
+                            newSubscriptionTierWithProrationPrice == null &&
+                            newSubscriptionUnitWithProrationPrice == null &&
+                            newSubscriptionGroupedAllocationPrice == null &&
+                            newSubscriptionGroupedWithProratedMinimumPrice == null &&
+                            newSubscriptionBulkWithProrationPrice == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Price: $_json")
+                    }
+                    newSubscriptionUnitPrice?.validate()
+                    newSubscriptionPackagePrice?.validate()
+                    newSubscriptionMatrixPrice?.validate()
+                    newSubscriptionTieredPrice?.validate()
+                    newSubscriptionTieredBpsPrice?.validate()
+                    newSubscriptionBpsPrice?.validate()
+                    newSubscriptionBulkBpsPrice?.validate()
+                    newSubscriptionBulkPrice?.validate()
+                    newSubscriptionThresholdTotalAmountPrice?.validate()
+                    newSubscriptionTieredPackagePrice?.validate()
+                    newSubscriptionTieredWithMinimumPrice?.validate()
+                    newSubscriptionUnitWithPercentPrice?.validate()
+                    newSubscriptionPackageWithAllocationPrice?.validate()
+                    newSubscriptionTierWithProrationPrice?.validate()
+                    newSubscriptionUnitWithProrationPrice?.validate()
+                    newSubscriptionGroupedAllocationPrice?.validate()
+                    newSubscriptionGroupedWithProratedMinimumPrice?.validate()
+                    newSubscriptionBulkWithProrationPrice?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -26782,55 +35589,76 @@ constructor(
 
                     when (modelType) {
                         "unit" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>())?.let {
-                                return Price(newSubscriptionUnitPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionUnitPrice = it, _json = json)
+                                }
                         }
                         "package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionPackagePrice = it, _json = json)
                                 }
                         }
                         "matrix" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionMatrixPrice = it, _json = json)
                                 }
                         }
                         "tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredPrice = it, _json = json)
                                 }
                         }
                         "tiered_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredBpsPrice = it, _json = json)
                                 }
                         }
                         "bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>())?.let {
-                                return Price(newSubscriptionBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionBulkBpsPrice = it, _json = json)
                                 }
                         }
                         "bulk" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>())?.let {
-                                return Price(newSubscriptionBulkPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBulkPrice = it, _json = json)
+                                }
                         }
                         "threshold_total_amount" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionThresholdTotalAmountPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionThresholdTotalAmountPrice = it,
@@ -26842,7 +35670,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredPackagePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredPackagePrice = it,
@@ -26854,7 +35684,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredWithMinimumPrice = it,
@@ -26866,7 +35698,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithPercentPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithPercentPrice = it,
@@ -26878,7 +35712,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionPackageWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionPackageWithAllocationPrice = it,
@@ -26890,7 +35726,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTierWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTierWithProrationPrice = it,
@@ -26902,7 +35740,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithProrationPrice = it,
@@ -26914,7 +35754,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedAllocationPrice = it,
@@ -26926,7 +35768,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedWithProratedMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedWithProratedMinimumPrice = it,
@@ -26938,7 +35782,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionBulkWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionBulkWithProrationPrice = it,
@@ -27008,96 +35854,229 @@ constructor(
             class NewSubscriptionUnitPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+                fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -27105,19 +36084,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -27127,22 +36132,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitConfig: UnitConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitConfig: JsonField<UnitConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -27170,25 +36178,41 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
-                    fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                    fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
+
+                    fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                        this.unitConfig = unitConfig
+                    }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -27197,13 +36221,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -27220,13 +36251,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -27236,12 +36275,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -27256,11 +36302,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -27268,22 +36321,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -27300,22 +36362,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -27325,12 +36402,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -27339,11 +36424,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -27352,6 +36445,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -27534,18 +36635,34 @@ constructor(
                 class UnitConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Rate per unit of usage */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Rate per unit of usage */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitConfig = apply {
+                        if (!validated) {
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27555,7 +36672,7 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27566,7 +36683,12 @@ constructor(
                         }
 
                         /** Rate per unit of usage */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Rate per unit of usage */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -27625,22 +36747,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27650,8 +36796,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27665,10 +36811,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27789,22 +36942,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27814,8 +36991,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27830,10 +37007,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27963,6 +37147,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28044,96 +37236,229 @@ constructor(
             class NewSubscriptionPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_config") private val packageConfig: PackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -28141,19 +37466,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28163,22 +37514,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageConfig: PackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageConfig: JsonField<PackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -28207,17 +37561,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun packageConfig(packageConfig: PackageConfig) =
+                        packageConfig(JsonField.of(packageConfig))
 
-                    fun packageConfig(packageConfig: PackageConfig) = apply {
+                    fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                         this.packageConfig = packageConfig
                     }
 
@@ -28225,9 +37595,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -28236,13 +37605,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -28259,13 +37635,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -28275,12 +37659,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -28295,11 +37686,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -28307,22 +37705,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -28339,22 +37746,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -28364,12 +37786,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -28378,11 +37808,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -28391,6 +37829,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -28575,25 +38021,52 @@ constructor(
                 class PackageConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("package_amount") private val packageAmount: String,
-                    @JsonProperty("package_size") private val packageSize: Long,
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    private val packageAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    private val packageSize: JsonField<Long> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** A currency amount to rate usage by */
-                    @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                    fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                    /** A currency amount to rate usage by */
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    fun _packageAmount(): JsonField<String> = packageAmount
 
                     /**
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    fun _packageSize(): JsonField<Long> = packageSize
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageConfig = apply {
+                        if (!validated) {
+                            packageAmount()
+                            packageSize()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28603,8 +38076,8 @@ constructor(
 
                     class Builder {
 
-                        private var packageAmount: String? = null
-                        private var packageSize: Long? = null
+                        private var packageAmount: JsonField<String>? = null
+                        private var packageSize: JsonField<Long>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28616,7 +38089,11 @@ constructor(
                         }
 
                         /** A currency amount to rate usage by */
-                        fun packageAmount(packageAmount: String) = apply {
+                        fun packageAmount(packageAmount: String) =
+                            packageAmount(JsonField.of(packageAmount))
+
+                        /** A currency amount to rate usage by */
+                        fun packageAmount(packageAmount: JsonField<String>) = apply {
                             this.packageAmount = packageAmount
                         }
 
@@ -28624,7 +38101,13 @@ constructor(
                          * An integer amount to represent package size. For example, 1000 here would
                          * divide usage by 1000 before multiplying by package_amount in rating
                          */
-                        fun packageSize(packageSize: Long) = apply {
+                        fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                        /**
+                         * An integer amount to represent package size. For example, 1000 here would
+                         * divide usage by 1000 before multiplying by package_amount in rating
+                         */
+                        fun packageSize(packageSize: JsonField<Long>) = apply {
                             this.packageSize = packageSize
                         }
 
@@ -28688,22 +38171,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28713,8 +38220,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28728,10 +38235,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -28852,22 +38366,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28877,8 +38415,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28893,10 +38431,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -29026,6 +38571,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29107,96 +38660,229 @@ constructor(
             class NewSubscriptionMatrixPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -29204,19 +38890,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionMatrixPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        matrixConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -29226,22 +38938,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var matrixConfig: MatrixConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -29270,27 +38985,42 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixConfig(matrixConfig: MatrixConfig) =
+                        matrixConfig(JsonField.of(matrixConfig))
 
-                    fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                    fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                         this.matrixConfig = matrixConfig
                     }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -29299,13 +39029,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -29322,13 +39059,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -29338,12 +39083,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -29358,11 +39110,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -29370,22 +39129,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -29402,22 +39170,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -29427,12 +39210,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -29441,11 +39232,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -29454,6 +39253,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -29586,31 +39393,66 @@ constructor(
                 class MatrixConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixConfig = apply {
+                        if (!validated) {
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29620,17 +39462,17 @@ constructor(
 
                     class Builder {
 
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
                             defaultUnitAmount = matrixConfig.defaultUnitAmount
-                            dimensions = matrixConfig.dimensions.toMutableList()
-                            matrixValues = matrixConfig.matrixValues.toMutableList()
+                            dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                            matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -29638,29 +39480,61 @@ constructor(
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -29693,11 +39567,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -29707,28 +39581,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -29738,14 +39639,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -29756,8 +39658,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -29767,13 +39677,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -29804,7 +39724,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -29908,22 +39828,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29933,8 +39877,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -29948,10 +39892,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -30072,22 +40023,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30097,8 +40072,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -30113,10 +40088,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -30246,6 +40228,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30327,96 +40317,229 @@ constructor(
             class NewSubscriptionTieredPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+                fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -30424,19 +40547,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -30446,22 +40595,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredConfig: TieredConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredConfig: JsonField<TieredConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -30490,17 +40642,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredConfig(tieredConfig: TieredConfig) =
+                        tieredConfig(JsonField.of(tieredConfig))
 
-                    fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                    fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                         this.tieredConfig = tieredConfig
                     }
 
@@ -30508,9 +40676,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -30519,13 +40686,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -30542,13 +40716,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -30558,12 +40740,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -30578,11 +40767,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -30590,22 +40786,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -30622,22 +40827,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -30647,12 +40867,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -30661,11 +40889,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -30674,6 +40910,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -30858,18 +41102,34 @@ constructor(
                 class TieredConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30879,26 +41139,42 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredConfig: TieredConfig) = apply {
-                            tiers = tieredConfig.tiers.toMutableList()
+                            tiers = tieredConfig.tiers.map { it.toMutableList() }
                             additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                         }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for rating based on total usage quantities into the specified tier
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -30926,7 +41202,7 @@ constructor(
                         fun build(): TieredConfig =
                             TieredConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -30935,30 +41211,64 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("first_unit") private val firstUnit: Double,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("last_unit") private val lastUnit: Double?,
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("last_unit")
+                        @ExcludeMissing
+                        private val lastUnit: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                        fun firstUnit(): Double = firstUnit.getRequired("first_unit")
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(): Optional<Double> =
+                            Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        fun _firstUnit(): JsonField<Double> = firstUnit
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
                         @JsonProperty("last_unit")
-                        fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                        @ExcludeMissing
+                        fun _lastUnit(): JsonField<Double> = lastUnit
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                firstUnit()
+                                unitAmount()
+                                lastUnit()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -30968,9 +41278,9 @@ constructor(
 
                         class Builder {
 
-                            private var firstUnit: Double? = null
-                            private var unitAmount: String? = null
-                            private var lastUnit: Double? = null
+                            private var firstUnit: JsonField<Double>? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var lastUnit: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -30983,10 +41293,19 @@ constructor(
                             }
 
                             /** Inclusive tier starting value */
-                            fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                            fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                            /** Inclusive tier starting value */
+                            fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                                this.firstUnit = firstUnit
+                            }
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -30994,7 +41313,8 @@ constructor(
                              * Exclusive tier ending value. If null, this is treated as the last
                              * tier
                              */
-                            fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                            fun lastUnit(lastUnit: Double?) =
+                                lastUnit(JsonField.ofNullable(lastUnit))
 
                             /**
                              * Exclusive tier ending value. If null, this is treated as the last
@@ -31012,6 +41332,14 @@ constructor(
                             fun lastUnit(lastUnit: Optional<Double>) =
                                 lastUnit(lastUnit.orElse(null) as Double?)
 
+                            /**
+                             * Exclusive tier ending value. If null, this is treated as the last
+                             * tier
+                             */
+                            fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                                this.lastUnit = lastUnit
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -31091,22 +41419,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31116,8 +41468,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -31131,10 +41483,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -31255,22 +41614,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31280,8 +41663,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -31296,10 +41679,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -31429,6 +41819,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31510,97 +41908,230 @@ constructor(
             class NewSubscriptionTieredBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_bps_config")
+                @ExcludeMissing
+                private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredBpsConfig(): TieredBpsConfig =
+                    tieredBpsConfig.getRequired("tiered_bps_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_bps_config")
-                fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+                @ExcludeMissing
+                fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -31608,19 +42139,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredBpsPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredBpsConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -31630,22 +42187,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredBpsConfig: TieredBpsConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -31675,17 +42235,33 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
 
-                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                        tieredBpsConfig(JsonField.of(tieredBpsConfig))
+
+                    fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                         this.tieredBpsConfig = tieredBpsConfig
                     }
 
@@ -31693,9 +42269,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -31704,13 +42279,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -31727,13 +42309,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -31743,12 +42333,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -31763,11 +42360,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -31775,22 +42379,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -31807,22 +42420,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -31832,12 +42460,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -31846,11 +42482,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -31859,6 +42503,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -32043,7 +42695,9 @@ constructor(
                 class TieredBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -32052,12 +42706,29 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32067,13 +42738,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                            tiers = tieredBpsConfig.tiers.toMutableList()
+                            tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties =
                                 tieredBpsConfig.additionalProperties.toMutableMap()
                         }
@@ -32082,14 +42753,31 @@ constructor(
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                         * specified tiers
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -32117,7 +42805,7 @@ constructor(
                         fun build(): TieredBpsConfig =
                             TieredBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -32126,33 +42814,71 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("minimum_amount") private val minimumAmount: String,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Per-event basis point rate */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                        fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Per-event basis point rate */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        fun _minimumAmount(): JsonField<String> = minimumAmount
 
                         /** Exclusive tier ending value */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** Per unit maximum to charge */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                minimumAmount()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -32162,10 +42888,10 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var minimumAmount: String? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var minimumAmount: JsonField<String>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -32179,31 +42905,46 @@ constructor(
                             }
 
                             /** Per-event basis point rate */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Per-event basis point rate */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Inclusive tier starting value */
-                            fun minimumAmount(minimumAmount: String) = apply {
+                            fun minimumAmount(minimumAmount: String) =
+                                minimumAmount(JsonField.of(minimumAmount))
+
+                            /** Inclusive tier starting value */
+                            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                                 this.minimumAmount = minimumAmount
                             }
 
                             /** Exclusive tier ending value */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Exclusive tier ending value */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** Per unit maximum to charge */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Exclusive tier ending value */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** Per unit maximum to charge */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -32282,22 +43023,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32307,8 +43072,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -32322,10 +43087,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -32446,22 +43218,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32471,8 +43267,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -32487,10 +43283,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -32620,6 +43423,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32701,96 +43512,229 @@ constructor(
             class NewSubscriptionBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+                fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -32798,19 +43742,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBpsPrice = apply {
+                    if (!validated) {
+                        bpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -32820,22 +43790,25 @@ constructor(
 
                 class Builder {
 
-                    private var bpsConfig: BpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bpsConfig: JsonField<BpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -32862,26 +43835,42 @@ constructor(
                             newSubscriptionBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                    fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                    fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                        this.bpsConfig = bpsConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -32890,13 +43879,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -32913,13 +43909,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -32929,12 +43933,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -32949,11 +43960,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -32961,22 +43979,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -32993,22 +44020,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -33018,12 +44060,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -33032,11 +44082,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -33045,6 +44103,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -33093,23 +44159,45 @@ constructor(
                 class BpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis point take rate per event */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis point take rate per event */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Optional currency amount maximum to cap spend per event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BpsConfig = apply {
+                        if (!validated) {
+                            bps()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33119,8 +44207,8 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33132,17 +44220,24 @@ constructor(
                         }
 
                         /** Basis point take rate per event */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis point take rate per event */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Optional currency amount maximum to cap spend per event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
-                        }
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                         /** Optional currency amount maximum to cap spend per event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Optional currency amount maximum to cap spend per event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -33333,22 +44428,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33358,8 +44477,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33373,10 +44492,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -33497,22 +44623,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33522,8 +44672,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33538,10 +44688,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -33671,6 +44828,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33752,96 +44917,229 @@ constructor(
             class NewSubscriptionBulkBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+                fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -33849,19 +45147,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkBpsPrice = apply {
+                    if (!validated) {
+                        bulkBpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -33871,22 +45195,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkBpsConfig: BulkBpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -33914,28 +45241,43 @@ constructor(
                                 newSubscriptionBulkBpsPrice.additionalProperties.toMutableMap()
                         }
 
-                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                        bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                    fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                         this.bulkBpsConfig = bulkBpsConfig
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -33944,13 +45286,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -33967,13 +45316,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -33983,12 +45340,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -34003,11 +45367,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -34015,22 +45386,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -34047,22 +45427,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -34072,12 +45467,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -34086,11 +45489,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -34099,6 +45510,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -34149,7 +45568,9 @@ constructor(
                 class BulkBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -34158,12 +45579,29 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34173,13 +45611,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                            tiers = bulkBpsConfig.tiers.toMutableList()
+                            tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                         }
 
@@ -34187,14 +45625,31 @@ constructor(
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a bulk BPS pricing model where all usage is aggregated to a
+                         * single tier based on total volume
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -34222,7 +45677,7 @@ constructor(
                         fun build(): BulkBpsConfig =
                             BulkBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -34231,29 +45686,59 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Basis points to rate on */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Upper bound for tier */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Basis points to rate on */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Upper bound for tier */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** The maximum amount to charge for any one event */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -34263,9 +45748,9 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -34278,26 +45763,37 @@ constructor(
                             }
 
                             /** Basis points to rate on */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Basis points to rate on */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Upper bound for tier */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Upper bound for tier */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** The maximum amount to charge for any one event */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Upper bound for tier */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** The maximum amount to charge for any one event */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -34507,22 +46003,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34532,8 +46052,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -34547,10 +46067,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -34671,22 +46198,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34696,8 +46247,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -34712,10 +46263,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -34845,6 +46403,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34926,96 +46492,229 @@ constructor(
             class NewSubscriptionBulkPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+                fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -35023,19 +46722,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkPrice = apply {
+                    if (!validated) {
+                        bulkConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -35045,22 +46770,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkConfig: BulkConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkConfig: JsonField<BulkConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -35087,26 +46815,42 @@ constructor(
                             newSubscriptionBulkPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                    fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                    fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                        this.bulkConfig = bulkConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -35115,13 +46859,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -35138,13 +46889,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -35154,12 +46913,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -35174,11 +46940,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -35186,22 +46959,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -35218,22 +47000,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -35243,12 +47040,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -35257,11 +47062,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -35270,6 +47083,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -35318,18 +47139,34 @@ constructor(
                 class BulkConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Bulk tiers for rating based on total usage volume */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35339,22 +47176,36 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkConfig: BulkConfig) = apply {
-                            tiers = bulkConfig.tiers.toMutableList()
+                            tiers = bulkConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                         }
 
                         /** Bulk tiers for rating based on total usage volume */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /** Bulk tiers for rating based on total usage volume */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /** Bulk tiers for rating based on total usage volume */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -35382,7 +47233,7 @@ constructor(
                         fun build(): BulkConfig =
                             BulkConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -35391,24 +47242,48 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_units")
+                        @ExcludeMissing
+                        private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /** Upper bound for this tier */
+                        fun maximumUnits(): Optional<Double> =
+                            Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /** Upper bound for this tier */
                         @JsonProperty("maximum_units")
-                        fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                        @ExcludeMissing
+                        fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                unitAmount()
+                                maximumUnits()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -35418,8 +47293,8 @@ constructor(
 
                         class Builder {
 
-                            private var unitAmount: String? = null
-                            private var maximumUnits: Double? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var maximumUnits: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -35431,14 +47306,17 @@ constructor(
                             }
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
                             /** Upper bound for this tier */
-                            fun maximumUnits(maximumUnits: Double?) = apply {
-                                this.maximumUnits = maximumUnits
-                            }
+                            fun maximumUnits(maximumUnits: Double?) =
+                                maximumUnits(JsonField.ofNullable(maximumUnits))
 
                             /** Upper bound for this tier */
                             fun maximumUnits(maximumUnits: Double) =
@@ -35451,6 +47329,11 @@ constructor(
                             fun maximumUnits(maximumUnits: Optional<Double>) =
                                 maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                            /** Upper bound for this tier */
+                            fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                                this.maximumUnits = maximumUnits
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -35661,22 +47544,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35686,8 +47593,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -35701,10 +47608,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -35825,22 +47739,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35850,8 +47788,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -35866,10 +47804,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -35999,6 +47944,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36080,42 +48033,166 @@ constructor(
             class NewSubscriptionThresholdTotalAmountPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("threshold_total_amount_config")
-                private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("threshold_total_amount_config")
                 fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                    thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("threshold_total_amount_config")
+                @ExcludeMissing
+                fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                     thresholdTotalAmountConfig
 
                 /**
@@ -36123,56 +48200,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -36180,19 +48266,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionThresholdTotalAmountPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        thresholdTotalAmountConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -36202,22 +48314,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -36252,27 +48368,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun thresholdTotalAmountConfig(
                         thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                    ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                    fun thresholdTotalAmountConfig(
+                        thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                     ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -36281,13 +48413,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -36304,13 +48443,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -36320,12 +48467,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -36340,11 +48494,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -36352,22 +48513,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -36384,22 +48554,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -36409,12 +48594,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -36423,11 +48616,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -36436,6 +48637,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -36628,6 +48837,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): ThresholdTotalAmountConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36699,22 +48916,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36724,8 +48965,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -36739,10 +48980,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -36863,22 +49111,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36888,8 +49160,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -36904,10 +49176,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -37037,6 +49316,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37118,98 +49405,230 @@ constructor(
             class NewSubscriptionTieredPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_package_config")
-                private val tieredPackageConfig: TieredPackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageConfig(): TieredPackageConfig =
+                    tieredPackageConfig.getRequired("tiered_package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_config")
-                fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+                @ExcludeMissing
+                fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -37217,19 +49636,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -37239,22 +49684,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageConfig: TieredPackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -37284,27 +49732,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                        this.tieredPackageConfig = tieredPackageConfig
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
                     }
 
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                        tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                    fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                        apply {
+                            this.tieredPackageConfig = tieredPackageConfig
+                        }
+
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -37313,13 +49777,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -37336,13 +49807,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -37352,12 +49831,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -37372,11 +49858,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -37384,22 +49877,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -37416,22 +49918,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -37441,12 +49958,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -37455,11 +49980,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -37468,6 +50001,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -37660,6 +50201,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37730,22 +50279,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37755,8 +50328,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -37770,10 +50343,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -37894,22 +50474,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37919,8 +50523,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -37935,10 +50539,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -38068,6 +50679,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38149,98 +50768,232 @@ constructor(
             class NewSubscriptionTieredWithMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_minimum_config")
-                private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                    tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_minimum_config")
-                fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+                @ExcludeMissing
+                fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                    tieredWithMinimumConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -38248,19 +51001,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -38270,22 +51049,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -38319,28 +51101,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                        apply {
-                            this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                        }
+                        tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                    fun tieredWithMinimumConfig(
+                        tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                    ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -38349,13 +51145,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -38372,13 +51175,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -38388,12 +51199,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -38408,11 +51226,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -38420,22 +51245,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -38452,22 +51286,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -38477,12 +51326,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -38491,11 +51348,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -38504,6 +51369,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -38696,6 +51569,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38767,22 +51648,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38792,8 +51697,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -38807,10 +51712,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -38931,22 +51843,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38956,8 +51892,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -38972,10 +51908,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -39105,6 +52048,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39186,98 +52137,232 @@ constructor(
             class NewSubscriptionUnitWithPercentPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_percent_config")
-                private val unitWithPercentConfig: UnitWithPercentConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithPercentConfig(): UnitWithPercentConfig =
+                    unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_percent_config")
-                fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+                @ExcludeMissing
+                fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> =
+                    unitWithPercentConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -39285,19 +52370,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithPercentPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithPercentConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -39307,22 +52418,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -39353,28 +52467,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
-                        apply {
-                            this.unitWithPercentConfig = unitWithPercentConfig
-                        }
+                        unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                    fun unitWithPercentConfig(
+                        unitWithPercentConfig: JsonField<UnitWithPercentConfig>
+                    ) = apply { this.unitWithPercentConfig = unitWithPercentConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -39383,13 +52511,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -39406,13 +52541,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -39422,12 +52565,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -39442,11 +52592,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -39454,22 +52611,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -39486,22 +52652,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -39511,12 +52692,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -39525,11 +52714,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -39538,6 +52735,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -39730,6 +52935,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithPercentConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39800,22 +53013,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39825,8 +53062,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -39840,10 +53077,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -39964,22 +53208,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39989,8 +53257,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -40005,10 +53273,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -40138,6 +53413,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40219,42 +53502,166 @@ constructor(
             class NewSubscriptionPackageWithAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("package_with_allocation_config")
-                private val packageWithAllocationConfig: PackageWithAllocationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("package_with_allocation_config")
                 fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                    packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("package_with_allocation_config")
+                @ExcludeMissing
+                fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                     packageWithAllocationConfig
 
                 /**
@@ -40262,56 +53669,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -40319,19 +53735,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackageWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageWithAllocationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -40341,22 +53783,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageWithAllocationConfig:
+                        JsonField<PackageWithAllocationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -40392,27 +53839,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun packageWithAllocationConfig(
                         packageWithAllocationConfig: PackageWithAllocationConfig
+                    ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                    fun packageWithAllocationConfig(
+                        packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                     ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -40421,13 +53884,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -40444,13 +53914,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -40460,12 +53938,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -40480,11 +53965,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -40492,22 +53984,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -40524,22 +54025,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -40549,12 +54065,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -40563,11 +54087,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -40576,6 +54108,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -40768,6 +54308,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageWithAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40840,22 +54388,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40865,8 +54437,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -40880,10 +54452,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -41004,22 +54583,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41029,8 +54632,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -41045,10 +54648,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -41178,6 +54788,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41259,42 +54877,166 @@ constructor(
             class NewSubscriptionTierWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_proration_config")
-                private val tieredWithProrationConfig: TieredWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_with_proration_config")
                 fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                    tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_with_proration_config")
+                @ExcludeMissing
+                fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
                     tieredWithProrationConfig
 
                 /**
@@ -41302,56 +55044,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -41359,19 +55110,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTierWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -41381,22 +55158,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -41430,27 +55211,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithProrationConfig(
                         tieredWithProrationConfig: TieredWithProrationConfig
+                    ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                    fun tieredWithProrationConfig(
+                        tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                     ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -41459,13 +55256,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -41482,13 +55286,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -41498,12 +55310,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -41518,11 +55337,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -41530,22 +55356,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -41562,22 +55397,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -41587,12 +55437,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -41601,11 +55459,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -41614,6 +55480,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -41806,6 +55680,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41877,22 +55759,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41902,8 +55808,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -41917,10 +55823,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -42041,22 +55954,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42066,8 +56003,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -42082,10 +56019,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -42215,6 +56159,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42296,98 +56248,232 @@ constructor(
             class NewSubscriptionUnitWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_proration_config")
-                private val unitWithProrationConfig: UnitWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithProrationConfig(): UnitWithProrationConfig =
+                    unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_proration_config")
-                fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+                @ExcludeMissing
+                fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                    unitWithProrationConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -42395,19 +56481,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -42417,22 +56529,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -42466,28 +56581,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                        apply {
-                            this.unitWithProrationConfig = unitWithProrationConfig
-                        }
+                        unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                    fun unitWithProrationConfig(
+                        unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                    ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -42496,13 +56625,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -42519,13 +56655,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -42535,12 +56679,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -42555,11 +56706,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -42567,22 +56725,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -42599,22 +56766,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -42624,12 +56806,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -42638,11 +56828,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -42651,6 +56849,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -42843,6 +57049,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42914,22 +57128,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42939,8 +57177,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -42954,10 +57192,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -43078,22 +57323,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43103,8 +57372,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -43119,10 +57388,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -43252,6 +57528,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43333,98 +57617,232 @@ constructor(
             class NewSubscriptionGroupedAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_allocation_config")
-                private val groupedAllocationConfig: GroupedAllocationConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                fun groupedAllocationConfig(): GroupedAllocationConfig =
+                    groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 @JsonProperty("grouped_allocation_config")
-                fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+                @ExcludeMissing
+                fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                    groupedAllocationConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -43432,19 +57850,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedAllocationConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -43454,22 +57898,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -43503,28 +57950,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                        apply {
-                            this.groupedAllocationConfig = groupedAllocationConfig
-                        }
+                        groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                    fun groupedAllocationConfig(
+                        groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                    ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -43533,13 +57994,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -43556,13 +58024,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -43572,12 +58048,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -43592,11 +58075,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -43604,22 +58094,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -43636,22 +58135,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -43661,12 +58175,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -43675,11 +58197,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -43688,6 +58218,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -43828,6 +58366,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43951,22 +58497,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43976,8 +58546,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -43991,10 +58561,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -44115,22 +58692,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44140,8 +58741,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -44156,10 +58757,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -44289,6 +58897,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44370,99 +58986,235 @@ constructor(
             class NewSubscriptionGroupedWithProratedMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_with_prorated_minimum_config")
-                private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
-                @JsonProperty("grouped_with_prorated_minimum_config")
                 fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
-                    groupedWithProratedMinimumConfig
+                    groupedWithProratedMinimumConfig.getRequired(
+                        "grouped_with_prorated_minimum_config"
+                    )
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                @JsonProperty("grouped_with_prorated_minimum_config")
+                @ExcludeMissing
+                fun _groupedWithProratedMinimumConfig():
+                    JsonField<GroupedWithProratedMinimumConfig> = groupedWithProratedMinimumConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -44470,19 +59222,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedWithProratedMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedWithProratedMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -44492,24 +59270,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
+                    private var cadence: JsonField<Cadence>? = null
                     private var groupedWithProratedMinimumConfig:
-                        GroupedWithProratedMinimumConfig? =
+                        JsonField<GroupedWithProratedMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -44550,29 +59331,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedWithProratedMinimumConfig(
                         groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                    ) =
+                        groupedWithProratedMinimumConfig(
+                            JsonField.of(groupedWithProratedMinimumConfig)
+                        )
+
+                    fun groupedWithProratedMinimumConfig(
+                        groupedWithProratedMinimumConfig:
+                            JsonField<GroupedWithProratedMinimumConfig>
                     ) = apply {
                         this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -44581,13 +59382,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -44604,13 +59412,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -44620,12 +59436,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -44640,11 +59463,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -44652,22 +59482,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -44684,22 +59523,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -44709,12 +59563,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -44723,11 +59585,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -44736,6 +59606,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -44876,6 +59754,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithProratedMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45001,22 +59887,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45026,8 +59936,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -45041,10 +59951,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -45165,22 +60082,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45190,8 +60131,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -45206,10 +60147,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -45339,6 +60287,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45421,97 +60377,231 @@ constructor(
             @JsonCreator
             private constructor(
                 @JsonProperty("bulk_with_proration_config")
-                private val bulkWithProrationConfig: BulkWithProrationConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                    bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
                 @JsonProperty("bulk_with_proration_config")
-                fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+                @ExcludeMissing
+                fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                    bulkWithProrationConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -45519,19 +60609,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkWithProrationPrice = apply {
+                    if (!validated) {
+                        bulkWithProrationConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -45541,22 +60657,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -45590,28 +60709,42 @@ constructor(
                     }
 
                     fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                        apply {
-                            this.bulkWithProrationConfig = bulkWithProrationConfig
-                        }
+                        bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                    fun bulkWithProrationConfig(
+                        bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                    ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -45620,13 +60753,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -45643,13 +60783,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -45659,12 +60807,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -45679,11 +60834,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -45691,22 +60853,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -45723,22 +60894,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -45748,12 +60934,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -45762,11 +60956,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -45775,6 +60977,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -45833,6 +61043,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -46038,22 +61256,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -46063,8 +61305,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -46078,10 +61320,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -46202,22 +61451,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -46227,8 +61500,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -46243,10 +61516,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -46376,6 +61656,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateResponse.kt
index 9172a8a2..76faccfb 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionCreateResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,40 +439,41 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(subscriptionCreateResponse: SubscriptionCreateResponse) = apply {
             id = subscriptionCreateResponse.id
             activePlanPhaseOrder = subscriptionCreateResponse.activePlanPhaseOrder
-            adjustmentIntervals = subscriptionCreateResponse.adjustmentIntervals
+            adjustmentIntervals =
+                subscriptionCreateResponse.adjustmentIntervals.map { it.toMutableList() }
             autoCollection = subscriptionCreateResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionCreateResponse.billingCycleAnchorConfiguration
@@ -462,16 +483,20 @@ private constructor(
             currentBillingPeriodStartDate = subscriptionCreateResponse.currentBillingPeriodStartDate
             customer = subscriptionCreateResponse.customer
             defaultInvoiceMemo = subscriptionCreateResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionCreateResponse.discountIntervals
+            discountIntervals =
+                subscriptionCreateResponse.discountIntervals.map { it.toMutableList() }
             endDate = subscriptionCreateResponse.endDate
-            fixedFeeQuantitySchedule = subscriptionCreateResponse.fixedFeeQuantitySchedule
+            fixedFeeQuantitySchedule =
+                subscriptionCreateResponse.fixedFeeQuantitySchedule.map { it.toMutableList() }
             invoicingThreshold = subscriptionCreateResponse.invoicingThreshold
-            maximumIntervals = subscriptionCreateResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionCreateResponse.maximumIntervals.map { it.toMutableList() }
             metadata = subscriptionCreateResponse.metadata
-            minimumIntervals = subscriptionCreateResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionCreateResponse.minimumIntervals.map { it.toMutableList() }
             netTerms = subscriptionCreateResponse.netTerms
             plan = subscriptionCreateResponse.plan
-            priceIntervals = subscriptionCreateResponse.priceIntervals
+            priceIntervals = subscriptionCreateResponse.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscriptionCreateResponse.redeemedCoupon
             startDate = subscriptionCreateResponse.startDate
             status = subscriptionCreateResponse.status
@@ -483,9 +508,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -498,15 +532,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -552,8 +617,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -570,8 +643,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -626,8 +707,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -643,11 +731,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -657,10 +762,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -672,7 +796,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -695,7 +833,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -734,11 +886,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -779,31 +948,55 @@ private constructor(
 
         fun build(): SubscriptionCreateResponse =
             SubscriptionCreateResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -844,20 +1037,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -885,18 +1084,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -912,6 +1112,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -919,11 +1134,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -957,11 +1190,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1264,11 +1500,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1276,12 +1512,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1289,15 +1525,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1327,13 +1563,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1341,7 +1577,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1381,7 +1618,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1399,9 +1650,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1409,7 +1669,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1438,13 +1701,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1576,16 +1850,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1593,7 +1867,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1601,15 +1875,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1639,13 +1913,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1653,7 +1927,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1679,7 +1956,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1712,9 +2003,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1722,7 +2022,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1751,13 +2054,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1888,16 +2202,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1905,21 +2219,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1949,20 +2265,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1988,7 +2305,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2006,9 +2337,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2016,7 +2356,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2060,13 +2403,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2203,16 +2557,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2220,24 +2574,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2268,21 +2624,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2308,7 +2665,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2347,9 +2718,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2357,7 +2737,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2386,14 +2769,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2524,16 +2918,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2541,21 +2935,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2585,20 +2981,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2623,7 +3020,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2656,9 +3067,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2666,7 +3086,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2695,13 +3118,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2834,19 +3268,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2872,7 +3306,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2907,7 +3341,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2919,7 +3366,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2948,7 +3408,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3200,25 +3660,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3247,19 +3715,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3282,7 +3752,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3292,9 +3776,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3303,7 +3802,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3340,12 +3842,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3468,25 +3978,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3515,18 +4031,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3541,7 +4061,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3551,9 +4085,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3562,7 +4111,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3612,12 +4164,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3743,26 +4303,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3791,18 +4359,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3816,7 +4386,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3826,9 +4410,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3837,7 +4436,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3889,12 +4491,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3998,13 +4608,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4031,10 +4645,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4046,7 +4660,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4085,10 +4701,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4158,24 +4774,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4203,17 +4825,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4226,7 +4849,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4236,11 +4873,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4288,11 +4943,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4442,24 +5103,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4487,17 +5154,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4510,7 +5178,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4520,11 +5202,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4572,11 +5272,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4911,10 +5617,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4923,7 +5631,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4932,13 +5640,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4946,7 +5657,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5176,13 +5888,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5213,15 +5927,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5231,7 +5946,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5255,8 +5971,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5272,8 +5996,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5288,7 +6021,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5301,8 +6040,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5310,7 +6057,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5772,6 +6541,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5807,14 +6641,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5842,11 +6685,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5872,9 +6717,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5925,9 +6770,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5992,11 +6839,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6022,9 +6873,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6039,7 +6890,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6070,9 +6923,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6172,7 +7025,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6196,7 +7051,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6205,7 +7060,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6228,7 +7085,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsParams.kt
index 0b39fcbf..bd9c0c11 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsParams.kt
@@ -14,6 +14,17 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to fetch a day-by-day snapshot of a subscription's costs in Orb, calculated
+ * by applying pricing information to the underlying usage (see the
+ * [subscription usage endpoint](fetch-subscription-usage) to fetch usage per metric, in usage units
+ * rather than a currency).
+ *
+ * The semantics of this endpoint exactly mirror those of
+ * [fetching a customer's costs](fetch-customer-costs). Use this endpoint to limit your analysis of
+ * costs to a specific subscription for the customer (e.g. to de-aggregate costs when a customer's
+ * subscription has started and stopped on the same day).
+ */
 class SubscriptionFetchCostsParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsResponse.kt
index 0c968d8a..bb8364a1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchCostsResponse.kt
@@ -29,7 +29,7 @@ private constructor(
 
     fun data(): List<Data> = data.getRequired("data")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -53,19 +53,34 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Data>> = JsonMissing.of()
+        private var data: JsonField<MutableList<Data>>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(subscriptionFetchCostsResponse: SubscriptionFetchCostsResponse) = apply {
-            data = subscriptionFetchCostsResponse.data
+            data = subscriptionFetchCostsResponse.data.map { it.toMutableList() }
             additionalProperties =
                 subscriptionFetchCostsResponse.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Data>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Data>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Data) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
             this.additionalProperties.clear()
@@ -88,7 +103,8 @@ private constructor(
 
         fun build(): SubscriptionFetchCostsResponse =
             SubscriptionFetchCostsResponse(
-                data.map { it.toImmutable() },
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
                 additionalProperties.toImmutable()
             )
     }
@@ -128,17 +144,23 @@ private constructor(
         /** Total costs for the timeframe, including any minimums and discounts. */
         fun total(): String = total.getRequired("total")
 
-        @JsonProperty("per_price_costs") @ExcludeMissing fun _perPriceCosts() = perPriceCosts
+        @JsonProperty("per_price_costs")
+        @ExcludeMissing
+        fun _perPriceCosts(): JsonField<List<PerPriceCost>> = perPriceCosts
 
         /** Total costs for the timeframe, excluding any minimums and discounts. */
-        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+        @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
-        @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+        @JsonProperty("timeframe_end")
+        @ExcludeMissing
+        fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
-        @JsonProperty("timeframe_start") @ExcludeMissing fun _timeframeStart() = timeframeStart
+        @JsonProperty("timeframe_start")
+        @ExcludeMissing
+        fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
         /** Total costs for the timeframe, including any minimums and discounts. */
-        @JsonProperty("total") @ExcludeMissing fun _total() = total
+        @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -166,16 +188,16 @@ private constructor(
 
         class Builder {
 
-            private var perPriceCosts: JsonField<List<PerPriceCost>> = JsonMissing.of()
-            private var subtotal: JsonField<String> = JsonMissing.of()
-            private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var total: JsonField<String> = JsonMissing.of()
+            private var perPriceCosts: JsonField<MutableList<PerPriceCost>>? = null
+            private var subtotal: JsonField<String>? = null
+            private var timeframeEnd: JsonField<OffsetDateTime>? = null
+            private var timeframeStart: JsonField<OffsetDateTime>? = null
+            private var total: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(data: Data) = apply {
-                perPriceCosts = data.perPriceCosts
+                perPriceCosts = data.perPriceCosts.map { it.toMutableList() }
                 subtotal = data.subtotal
                 timeframeEnd = data.timeframeEnd
                 timeframeStart = data.timeframeStart
@@ -187,7 +209,20 @@ private constructor(
                 perPriceCosts(JsonField.of(perPriceCosts))
 
             fun perPriceCosts(perPriceCosts: JsonField<List<PerPriceCost>>) = apply {
-                this.perPriceCosts = perPriceCosts
+                this.perPriceCosts = perPriceCosts.map { it.toMutableList() }
+            }
+
+            fun addPerPriceCost(perPriceCost: PerPriceCost) = apply {
+                perPriceCosts =
+                    (perPriceCosts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(perPriceCost)
+                    }
             }
 
             /** Total costs for the timeframe, excluding any minimums and discounts. */
@@ -237,11 +272,12 @@ private constructor(
 
             fun build(): Data =
                 Data(
-                    perPriceCosts.map { it.toImmutable() },
-                    subtotal,
-                    timeframeEnd,
-                    timeframeStart,
-                    total,
+                    checkNotNull(perPriceCosts) { "`perPriceCosts` is required but was not set" }
+                        .map { it.toImmutable() },
+                    checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                    checkNotNull(timeframeEnd) { "`timeframeEnd` is required but was not set" },
+                    checkNotNull(timeframeStart) { "`timeframeStart` is required but was not set" },
+                    checkNotNull(total) { "`total` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -733,16 +769,16 @@ private constructor(
              * }
              * ```
              */
-            @JsonProperty("price") @ExcludeMissing fun _price() = price
+            @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
             /** Price's contributions for the timeframe, excluding any minimums and discounts. */
-            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal() = subtotal
+            @JsonProperty("subtotal") @ExcludeMissing fun _subtotal(): JsonField<String> = subtotal
 
             /** Price's contributions for the timeframe, including minimums and discounts. */
-            @JsonProperty("total") @ExcludeMissing fun _total() = total
+            @JsonProperty("total") @ExcludeMissing fun _total(): JsonField<String> = total
 
             /** The price's quantity for the timeframe */
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -769,9 +805,9 @@ private constructor(
 
             class Builder {
 
-                private var price: JsonField<Price> = JsonMissing.of()
-                private var subtotal: JsonField<String> = JsonMissing.of()
-                private var total: JsonField<String> = JsonMissing.of()
+                private var price: JsonField<Price>? = null
+                private var subtotal: JsonField<String>? = null
+                private var total: JsonField<String>? = null
                 private var quantity: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
@@ -1252,6 +1288,73 @@ private constructor(
                  */
                 fun price(price: JsonField<Price>) = apply { this.price = price }
 
+                fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+                fun price(packagePrice: Price.PackagePrice) =
+                    price(Price.ofPackagePrice(packagePrice))
+
+                fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+                fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+                fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                    price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+                fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+                fun price(bulkBpsPrice: Price.BulkBpsPrice) =
+                    price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+                fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+                fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                    price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+                fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                    price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+                fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                    price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+                fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                    price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+                fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                    price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+                fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                    price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+                fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                    price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+                fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                    price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+                fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                    price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+                fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                    price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+                fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                    price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+                fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                    price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+                fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                    price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+                fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                    price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+                fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                    price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+                fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                    price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
                 /**
                  * Price's contributions for the timeframe, excluding any minimums and discounts.
                  */
@@ -1269,7 +1372,15 @@ private constructor(
                 fun total(total: JsonField<String>) = apply { this.total = total }
 
                 /** The price's quantity for the timeframe */
-                fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
+                fun quantity(quantity: Double?) = quantity(JsonField.ofNullable(quantity))
+
+                /** The price's quantity for the timeframe */
+                fun quantity(quantity: Double) = quantity(quantity as Double?)
+
+                /** The price's quantity for the timeframe */
+                @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                fun quantity(quantity: Optional<Double>) =
+                    quantity(quantity.orElse(null) as Double?)
 
                 /** The price's quantity for the timeframe */
                 fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
@@ -1298,9 +1409,9 @@ private constructor(
 
                 fun build(): PerPriceCost =
                     PerPriceCost(
-                        price,
-                        subtotal,
-                        total,
+                        checkNotNull(price) { "`price` is required but was not set" },
+                        checkNotNull(subtotal) { "`subtotal` is required but was not set" },
+                        checkNotNull(total) { "`total` is required but was not set" },
                         quantity,
                         additionalProperties.toImmutable(),
                     )
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchParams.kt
index 05cd1a6a..4799e9c1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchParams.kt
@@ -7,6 +7,10 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint is used to fetch a [Subscription](../guides/concepts#subscription) given an
+ * identifier.
+ */
 class SubscriptionFetchParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleParams.kt
index 5e4efdc6..59b587a1 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleParams.kt
@@ -10,6 +10,11 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a [paginated](../reference/pagination) list of all plans associated with a
+ * subscription along with their start and end dates. This list contains the subscription's initial
+ * plan along with past and future plan changes.
+ */
 class SubscriptionFetchScheduleParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleResponse.kt
index 5cf15f0d..2b331445 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchScheduleResponse.kt
@@ -42,13 +42,17 @@ private constructor(
 
     fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -75,10 +79,10 @@ private constructor(
 
     class Builder {
 
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var plan: JsonField<Plan>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -96,7 +100,9 @@ private constructor(
 
         fun createdAt(createdAt: JsonField<OffsetDateTime>) = apply { this.createdAt = createdAt }
 
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -129,10 +135,10 @@ private constructor(
 
         fun build(): SubscriptionFetchScheduleResponse =
             SubscriptionFetchScheduleResponse(
-                createdAt,
-                endDate,
-                plan,
-                startDate,
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -164,16 +170,18 @@ private constructor(
 
         fun name(): Optional<String> = Optional.ofNullable(name.getNullable("name"))
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /**
          * An optional user-defined ID for this plan resource, used throughout the system as an
          * alias for this Plan. Use this field to identify a plan by an existing identifier in your
          * system.
          */
-        @JsonProperty("external_plan_id") @ExcludeMissing fun _externalPlanId() = externalPlanId
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
-        @JsonProperty("name") @ExcludeMissing fun _name() = name
+        @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -199,9 +207,9 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var externalPlanId: JsonField<String> = JsonMissing.of()
-            private var name: JsonField<String> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var externalPlanId: JsonField<String>? = null
+            private var name: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -212,7 +220,9 @@ private constructor(
                 additionalProperties = plan.additionalProperties.toMutableMap()
             }
 
-            fun id(id: String) = id(JsonField.of(id))
+            fun id(id: String?) = id(JsonField.ofNullable(id))
+
+            fun id(id: Optional<String>) = id(id.orElse(null))
 
             fun id(id: JsonField<String>) = apply { this.id = id }
 
@@ -221,8 +231,16 @@ private constructor(
              * alias for this Plan. Use this field to identify a plan by an existing identifier in
              * your system.
              */
-            fun externalPlanId(externalPlanId: String) =
-                externalPlanId(JsonField.of(externalPlanId))
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
+
+            /**
+             * An optional user-defined ID for this plan resource, used throughout the system as an
+             * alias for this Plan. Use this field to identify a plan by an existing identifier in
+             * your system.
+             */
+            fun externalPlanId(externalPlanId: Optional<String>) =
+                externalPlanId(externalPlanId.orElse(null))
 
             /**
              * An optional user-defined ID for this plan resource, used throughout the system as an
@@ -233,7 +251,9 @@ private constructor(
                 this.externalPlanId = externalPlanId
             }
 
-            fun name(name: String) = name(JsonField.of(name))
+            fun name(name: String?) = name(JsonField.ofNullable(name))
+
+            fun name(name: Optional<String>) = name(name.orElse(null))
 
             fun name(name: JsonField<String>) = apply { this.name = name }
 
@@ -258,9 +278,9 @@ private constructor(
 
             fun build(): Plan =
                 Plan(
-                    id,
-                    externalPlanId,
-                    name,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(externalPlanId) { "`externalPlanId` is required but was not set" },
+                    checkNotNull(name) { "`name` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchUsageParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchUsageParams.kt
index dca1593f..edc34f62 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchUsageParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionFetchUsageParams.kt
@@ -14,6 +14,182 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to fetch a subscription's usage in Orb. Especially when combined with
+ * optional query parameters, this endpoint is a powerful way to build visualizations on top of
+ * Orb's event data and metrics.
+ *
+ * With no query parameters specified, this endpoint returns usage for the subscription's _current
+ * billing period_ across each billable metric that participates in the subscription. Usage
+ * quantities returned are the result of evaluating the metric definition for the entirety of the
+ * customer's billing period.
+ *
+ * ### Default response shape
+ *
+ * Orb returns a `data` array with an object corresponding to each billable metric. Nested within
+ * this object is a `usage` array which has a `quantity` value and a corresponding `timeframe_start`
+ * and `timeframe_end`. The `quantity` value represents the calculated usage value for the billable
+ * metric over the specified timeframe (inclusive of the `timeframe_start` timestamp and exclusive
+ * of the `timeframe_end` timestamp).
+ *
+ * Orb will include _every_ window in the response starting from the beginning of the billing
+ * period, even when there were no events (and therefore no usage) in the window. This increases the
+ * size of the response but prevents the caller from filling in gaps and handling cumbersome
+ * time-based logic.
+ *
+ * The query parameters in this endpoint serve to override this behavior and provide some key
+ * functionality, as listed below. Note that this functionality can also be used _in conjunction_
+ * with each other, e.g. to display grouped usage on a custom timeframe.
+ *
+ * ## Custom timeframe
+ *
+ * In order to view usage for a custom timeframe rather than the current billing period, specify a
+ * `timeframe_start` and `timeframe_end`. This will calculate quantities for usage incurred between
+ * timeframe_start (inclusive) and timeframe_end (exclusive), i.e. `[timeframe_start,
+ * timeframe_end)`.
+ *
+ * Note:
+ * - These timestamps must be specified in ISO 8601 format and UTC timezone, e.g.
+ *   `2022-02-01T05:00:00Z`.
+ * - Both parameters must be specified if either is specified.
+ *
+ * ## Grouping by custom attributes
+ *
+ * In order to view a single metric grouped by a specific _attribute_ that each event is tagged with
+ * (e.g. `cluster`), you must additionally specify a `billable_metric_id` and a `group_by` key. The
+ * `group_by` key denotes the event property on which to group.
+ *
+ * When returning grouped usage, only usage for `billable_metric_id` is returned, and a separate
+ * object in the `data` array is returned for each value of the `group_by` key present in your
+ * events. The `quantity` value is the result of evaluating the billable metric for events filtered
+ * to a single value of the `group_by` key.
+ *
+ * Orb expects that events that match the billable metric will contain values in the `properties`
+ * dictionary that correspond to the `group_by` key specified. By default, Orb will not return a
+ * `null` group (i.e. events that match the metric but do not have the key set). Currently, it is
+ * only possible to view usage grouped by a single attribute at a time.
+ *
+ * When viewing grouped usage, Orb uses pagination to limit the response size to 1000 groups by
+ * default. If there are more groups for a given subscription, pagination metadata in the response
+ * can be used to fetch all of the data.
+ *
+ * The following example shows usage for an "API Requests" billable metric grouped by `region`. Note
+ * the extra `metric_group` dictionary in the response, which provides metadata about the group:
+ * ```json
+ * {
+ *     "data": [
+ *         {
+ *             "usage": [
+ *                 {
+ *                     "quantity": 0.19291,
+ *                     "timeframe_start": "2021-10-01T07:00:00Z",
+ *                     "timeframe_end": "2021-10-02T07:00:00Z",
+ *                 },
+ *                 ...
+ *             ],
+ *             "metric_group": {
+ *                 "property_key": "region",
+ *                 "property_value": "asia/pacific"
+ *             },
+ *             "billable_metric": {
+ *                 "id": "Fe9pbpMk86xpwdGB",
+ *                 "name": "API Requests"
+ *             },
+ *             "view_mode": "periodic"
+ *         },
+ *         ...
+ *     ]
+ * }
+ * ```
+ *
+ * ## Windowed usage
+ *
+ * The `granularity` parameter can be used to _window_ the usage `quantity` value into periods. When
+ * not specified, usage is returned for the entirety of the time range.
+ *
+ * When `granularity = day` is specified with a timeframe longer than a day, Orb will return a
+ * `quantity` value for each full day between `timeframe_start` and `timeframe_end`. Note that the
+ * days are demarcated by the _customer's local midnight_.
+ *
+ * For example, with `timeframe_start = 2022-02-01T05:00:00Z`, `timeframe_end =
+ * 2022-02-04T01:00:00Z` and `granularity=day`, the following windows will be returned for a
+ * customer in the `America/Los_Angeles` timezone since local midnight is `08:00` UTC:
+ * - `[2022-02-01T05:00:00Z, 2022-02-01T08:00:00Z)`
+ * - `[2022-02-01T08:00:00, 2022-02-02T08:00:00Z)`
+ * - `[2022-02-02T08:00:00, 2022-02-03T08:00:00Z)`
+ * - `[2022-02-03T08:00:00, 2022-02-04T01:00:00Z)`
+ *
+ * ```json
+ * {
+ *     "data": [
+ *         {
+ *             "billable_metric": {
+ *                 "id": "Q8w89wjTtBdejXKsm",
+ *                 "name": "API Requests"
+ *             },
+ *             "usage": [
+ *                 {
+ *                     "quantity": 0,
+ *                     "timeframe_end": "2022-02-01T08:00:00+00:00",
+ *                     "timeframe_start": "2022-02-01T05:00:00+00:00"
+ *                 },
+ *                 {
+ *
+ *                     "quantity": 0,
+ *                     "timeframe_end": "2022-02-02T08:00:00+00:00",
+ *                     "timeframe_start": "2022-02-01T08:00:00+00:00"
+ *                 },
+ *                 {
+ *                     "quantity": 0,
+ *                     "timeframe_end": "2022-02-03T08:00:00+00:00",
+ *                     "timeframe_start": "2022-02-02T08:00:00+00:00"
+ *                 },
+ *                 {
+ *                     "quantity": 0,
+ *                     "timeframe_end": "2022-02-04T01:00:00+00:00",
+ *                     "timeframe_start": "2022-02-03T08:00:00+00:00"
+ *                 }
+ *             ],
+ *             "view_mode": "periodic"
+ *         },
+ *         ...
+ *     ]
+ * }
+ * ```
+ *
+ * ## Decomposable vs. non-decomposable metrics
+ *
+ * Billable metrics fall into one of two categories: decomposable and non-decomposable. A
+ * decomposable billable metric, such as a sum or a count, can be displayed and aggregated across
+ * arbitrary timescales. On the other hand, a non-decomposable metric is not meaningful when only a
+ * slice of the billing window is considered.
+ *
+ * As an example, if we have a billable metric that's defined to count unique users, displaying a
+ * graph of unique users for each day is not representative of the billable metric value over the
+ * month (days could have an overlapping set of 'unique' users). Instead, what's useful for any
+ * given day is the number of unique users in the billing period so far, which are the _cumulative_
+ * unique users.
+ *
+ * Accordingly, this endpoint returns treats these two types of metrics differently when `group_by`
+ * is specified:
+ * - Decomposable metrics can be grouped by any event property.
+ * - Non-decomposable metrics can only be grouped by the corresponding price's invoice grouping key.
+ *   If no invoice grouping key is present, the metric does not support `group_by`.
+ *
+ * ## Matrix prices
+ *
+ * When a billable metric is attached to a price that uses matrix pricing, it's important to view
+ * usage grouped by those matrix dimensions. In this case, use the query parameters
+ * `first_dimension_key`, `first_dimension_value` and `second_dimension_key`,
+ * `second_dimension_value` while filtering to a specific `billable_metric_id`.
+ *
+ * For example, if your compute metric has a separate unit price (i.e. a matrix pricing model) per
+ * `region` and `provider`, your request might provide the following parameters:
+ * - `first_dimension_key`: `region`
+ * - `first_dimension_value`: `us-east-1`
+ * - `second_dimension_key`: `provider`
+ * - `second_dimension_value`: `aws`
+ */
 class SubscriptionFetchUsageParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionListParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionListParams.kt
index 5ae61ad5..cdf0f4a4 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionListParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionListParams.kt
@@ -15,6 +15,16 @@ import java.time.format.DateTimeFormatter
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint returns a list of all subscriptions for an account as a
+ * [paginated](../reference/pagination) list, ordered starting from the most recently created
+ * subscription. For a full discussion of the subscription resource, see
+ * [Subscription](../guides/concepts#subscription).
+ *
+ * Subscriptions can be filtered for a specific customer by using either the customer_id or
+ * external_customer_id query parameters. To filter subscriptions for multiple customers, use the
+ * customer_id[] or external_customer_id[] query parameters.
+ */
 class SubscriptionListParams
 constructor(
     private val createdAtGt: OffsetDateTime?,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsParams.kt
index 6bc09978..1b90a79b 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -31,6 +32,71 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint is used to add and edit subscription
+ * [price intervals](../reference/price-interval). By making modifications to a subscription’s price
+ * intervals, you can
+ * [flexibly and atomically control the billing behavior of a subscription](../guides/product-catalog/modifying-subscriptions).
+ *
+ * ## Adding price intervals
+ *
+ * Prices can be added as price intervals to a subscription by specifying them in the `add` array. A
+ * `price_id` or `external_price_id` from an add-on price or previously removed plan price can be
+ * specified to reuse an existing price definition (however, please note that prices from other
+ * plans cannot be added to the subscription). Additionally, a new price can be specified using the
+ * `price` field — this price will be created automatically.
+ *
+ * A `start_date` must be specified for the price interval. This is the date when the price will
+ * start billing on the subscription, so this will notably result in an immediate charge at this
+ * time for any billed in advance fixed fees. The `end_date` will default to null, resulting in a
+ * price interval that will bill on a continually recurring basis. Both of these dates can be set in
+ * the past or the future and Orb will generate or modify invoices to ensure the subscription’s
+ * invoicing behavior is correct.
+ *
+ * Additionally, a discount, minimum, or maximum can be specified on the price interval. This will
+ * only apply to this price interval, not any other price intervals on the subscription.
+ *
+ * ## Adjustment intervals
+ *
+ * An adjustment interval represents the time period that a particular adjustment (a discount,
+ * minimum, or maximum) applies to the prices on a subscription. Adjustment intervals can be added
+ * to a subscription by specifying them in the `add_adjustments` array, or modified via the
+ * `edit_adjustments` array. When creating an adjustment interval, you'll need to provide the
+ * definition of the new adjustment (the type of adjustment, and which prices it applies to), as
+ * well as the start and end dates for the adjustment interval. The start and end dates of an
+ * existing adjustment interval can be edited via the `edit_adjustments` field (just like price
+ * intervals). (To "change" the amount of a discount, minimum, or maximum, then, you'll need to end
+ * the existing interval, and create a new adjustment interval with the new amount and a start date
+ * that matches the end date of the previous interval.)
+ *
+ * ## Editing price intervals
+ *
+ * Price intervals can be adjusted by specifying edits to make in the `edit` array. A
+ * `price_interval_id` to edit must be specified — this can be retrieved from the `price_intervals`
+ * field on the subscription.
+ *
+ * A new `start_date` or `end_date` can be specified to change the range of the price interval,
+ * which will modify past or future invoices to ensure correctness. If either of these dates are
+ * unspecified, they will default to the existing date on the price interval. To remove a price
+ * interval entirely from a subscription, set the `end_date` to be equivalent to the `start_date`.
+ *
+ * ## Fixed fee quantity transitions
+ *
+ * The fixed fee quantity transitions for a fixed fee price interval can also be specified when
+ * adding or editing by passing an array for `fixed_fee_quantity_transitions`. A fixed fee quantity
+ * transition must have a `quantity` and an `effective_date`, which is the date after which the new
+ * quantity will be used for billing. If a fixed fee quantity transition is scheduled at a billing
+ * period boundary, the full quantity will be billed on an invoice with the other prices on the
+ * subscription. If the fixed fee quantity transition is scheduled mid-billing period, the
+ * difference between the existing quantity and quantity specified in the transition will be
+ * prorated for the rest of the billing period and billed immediately, which will generate a new
+ * invoice.
+ *
+ * Notably, the list of fixed fee quantity transitions passed will overwrite the existing fixed fee
+ * quantity transitions on the price interval, so the entire list of transitions must be specified
+ * to add additional transitions. The existing list of transitions can be retrieved using the
+ * `fixed_fee_quantity_transitions` property on a subscription’s serialized price intervals.
+ */
 class SubscriptionPriceIntervalsParams
 constructor(
     private val subscriptionId: String,
@@ -53,12 +119,24 @@ constructor(
     /** A list of adjustments to edit on the subscription. */
     fun editAdjustments(): Optional<List<EditAdjustment>> = body.editAdjustments()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** A list of price intervals to add to the subscription. */
+    fun _add(): JsonField<List<Add>> = body._add()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /** A list of adjustments to add to the subscription. */
+    fun _addAdjustments(): JsonField<List<AddAdjustment>> = body._addAdjustments()
+
+    /** A list of price intervals to edit on the subscription. */
+    fun _edit(): JsonField<List<Edit>> = body._edit()
+
+    /** A list of adjustments to edit on the subscription. */
+    fun _editAdjustments(): JsonField<List<EditAdjustment>> = body._editAdjustments()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionPriceIntervalsBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -76,32 +154,68 @@ constructor(
     class SubscriptionPriceIntervalsBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("add") private val add: List<Add>?,
-        @JsonProperty("add_adjustments") private val addAdjustments: List<AddAdjustment>?,
-        @JsonProperty("edit") private val edit: List<Edit>?,
-        @JsonProperty("edit_adjustments") private val editAdjustments: List<EditAdjustment>?,
+        @JsonProperty("add")
+        @ExcludeMissing
+        private val add: JsonField<List<Add>> = JsonMissing.of(),
+        @JsonProperty("add_adjustments")
+        @ExcludeMissing
+        private val addAdjustments: JsonField<List<AddAdjustment>> = JsonMissing.of(),
+        @JsonProperty("edit")
+        @ExcludeMissing
+        private val edit: JsonField<List<Edit>> = JsonMissing.of(),
+        @JsonProperty("edit_adjustments")
+        @ExcludeMissing
+        private val editAdjustments: JsonField<List<EditAdjustment>> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** A list of price intervals to add to the subscription. */
-        @JsonProperty("add") fun add(): Optional<List<Add>> = Optional.ofNullable(add)
+        fun add(): Optional<List<Add>> = Optional.ofNullable(add.getNullable("add"))
+
+        /** A list of adjustments to add to the subscription. */
+        fun addAdjustments(): Optional<List<AddAdjustment>> =
+            Optional.ofNullable(addAdjustments.getNullable("add_adjustments"))
+
+        /** A list of price intervals to edit on the subscription. */
+        fun edit(): Optional<List<Edit>> = Optional.ofNullable(edit.getNullable("edit"))
+
+        /** A list of adjustments to edit on the subscription. */
+        fun editAdjustments(): Optional<List<EditAdjustment>> =
+            Optional.ofNullable(editAdjustments.getNullable("edit_adjustments"))
+
+        /** A list of price intervals to add to the subscription. */
+        @JsonProperty("add") @ExcludeMissing fun _add(): JsonField<List<Add>> = add
 
         /** A list of adjustments to add to the subscription. */
         @JsonProperty("add_adjustments")
-        fun addAdjustments(): Optional<List<AddAdjustment>> = Optional.ofNullable(addAdjustments)
+        @ExcludeMissing
+        fun _addAdjustments(): JsonField<List<AddAdjustment>> = addAdjustments
 
         /** A list of price intervals to edit on the subscription. */
-        @JsonProperty("edit") fun edit(): Optional<List<Edit>> = Optional.ofNullable(edit)
+        @JsonProperty("edit") @ExcludeMissing fun _edit(): JsonField<List<Edit>> = edit
 
         /** A list of adjustments to edit on the subscription. */
         @JsonProperty("edit_adjustments")
-        fun editAdjustments(): Optional<List<EditAdjustment>> = Optional.ofNullable(editAdjustments)
+        @ExcludeMissing
+        fun _editAdjustments(): JsonField<List<EditAdjustment>> = editAdjustments
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionPriceIntervalsBody = apply {
+            if (!validated) {
+                add().map { it.forEach { it.validate() } }
+                addAdjustments().map { it.forEach { it.validate() } }
+                edit().map { it.forEach { it.validate() } }
+                editAdjustments().map { it.forEach { it.validate() } }
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -111,72 +225,111 @@ constructor(
 
         class Builder {
 
-            private var add: MutableList<Add>? = null
-            private var addAdjustments: MutableList<AddAdjustment>? = null
-            private var edit: MutableList<Edit>? = null
-            private var editAdjustments: MutableList<EditAdjustment>? = null
+            private var add: JsonField<MutableList<Add>>? = null
+            private var addAdjustments: JsonField<MutableList<AddAdjustment>>? = null
+            private var edit: JsonField<MutableList<Edit>>? = null
+            private var editAdjustments: JsonField<MutableList<EditAdjustment>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(subscriptionPriceIntervalsBody: SubscriptionPriceIntervalsBody) =
                 apply {
-                    add = subscriptionPriceIntervalsBody.add?.toMutableList()
-                    addAdjustments = subscriptionPriceIntervalsBody.addAdjustments?.toMutableList()
-                    edit = subscriptionPriceIntervalsBody.edit?.toMutableList()
+                    add = subscriptionPriceIntervalsBody.add.map { it.toMutableList() }
+                    addAdjustments =
+                        subscriptionPriceIntervalsBody.addAdjustments.map { it.toMutableList() }
+                    edit = subscriptionPriceIntervalsBody.edit.map { it.toMutableList() }
                     editAdjustments =
-                        subscriptionPriceIntervalsBody.editAdjustments?.toMutableList()
+                        subscriptionPriceIntervalsBody.editAdjustments.map { it.toMutableList() }
                     additionalProperties =
                         subscriptionPriceIntervalsBody.additionalProperties.toMutableMap()
                 }
 
             /** A list of price intervals to add to the subscription. */
-            fun add(add: List<Add>?) = apply { this.add = add?.toMutableList() }
+            fun add(add: List<Add>) = add(JsonField.of(add))
 
             /** A list of price intervals to add to the subscription. */
-            fun add(add: Optional<List<Add>>) = add(add.orElse(null))
+            fun add(add: JsonField<List<Add>>) = apply { this.add = add.map { it.toMutableList() } }
 
             /** A list of price intervals to add to the subscription. */
             fun addAdd(add: Add) = apply {
-                this.add = (this.add ?: mutableListOf()).apply { add(add) }
+                this.add =
+                    (this.add ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(add)
+                    }
             }
 
             /** A list of adjustments to add to the subscription. */
-            fun addAdjustments(addAdjustments: List<AddAdjustment>?) = apply {
-                this.addAdjustments = addAdjustments?.toMutableList()
-            }
+            fun addAdjustments(addAdjustments: List<AddAdjustment>) =
+                addAdjustments(JsonField.of(addAdjustments))
 
             /** A list of adjustments to add to the subscription. */
-            fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
-                addAdjustments(addAdjustments.orElse(null))
+            fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+                this.addAdjustments = addAdjustments.map { it.toMutableList() }
+            }
 
             /** A list of adjustments to add to the subscription. */
             fun addAddAdjustment(addAdjustment: AddAdjustment) = apply {
-                addAdjustments = (addAdjustments ?: mutableListOf()).apply { add(addAdjustment) }
+                addAdjustments =
+                    (addAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(addAdjustment)
+                    }
             }
 
             /** A list of price intervals to edit on the subscription. */
-            fun edit(edit: List<Edit>?) = apply { this.edit = edit?.toMutableList() }
+            fun edit(edit: List<Edit>) = edit(JsonField.of(edit))
 
             /** A list of price intervals to edit on the subscription. */
-            fun edit(edit: Optional<List<Edit>>) = edit(edit.orElse(null))
+            fun edit(edit: JsonField<List<Edit>>) = apply {
+                this.edit = edit.map { it.toMutableList() }
+            }
 
             /** A list of price intervals to edit on the subscription. */
             fun addEdit(edit: Edit) = apply {
-                this.edit = (this.edit ?: mutableListOf()).apply { add(edit) }
+                this.edit =
+                    (this.edit ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(edit)
+                    }
             }
 
             /** A list of adjustments to edit on the subscription. */
-            fun editAdjustments(editAdjustments: List<EditAdjustment>?) = apply {
-                this.editAdjustments = editAdjustments?.toMutableList()
-            }
+            fun editAdjustments(editAdjustments: List<EditAdjustment>) =
+                editAdjustments(JsonField.of(editAdjustments))
 
             /** A list of adjustments to edit on the subscription. */
-            fun editAdjustments(editAdjustments: Optional<List<EditAdjustment>>) =
-                editAdjustments(editAdjustments.orElse(null))
+            fun editAdjustments(editAdjustments: JsonField<List<EditAdjustment>>) = apply {
+                this.editAdjustments = editAdjustments.map { it.toMutableList() }
+            }
 
             /** A list of adjustments to edit on the subscription. */
             fun addEditAdjustment(editAdjustment: EditAdjustment) = apply {
-                editAdjustments = (editAdjustments ?: mutableListOf()).apply { add(editAdjustment) }
+                editAdjustments =
+                    (editAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(editAdjustment)
+                    }
             }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
@@ -200,10 +353,10 @@ constructor(
 
             fun build(): SubscriptionPriceIntervalsBody =
                 SubscriptionPriceIntervalsBody(
-                    add?.toImmutable(),
-                    addAdjustments?.toImmutable(),
-                    edit?.toImmutable(),
-                    editAdjustments?.toImmutable(),
+                    (add ?: JsonMissing.of()).map { it.toImmutable() },
+                    (addAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (edit ?: JsonMissing.of()).map { it.toImmutable() },
+                    (editAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -255,22 +408,23 @@ constructor(
         fun subscriptionId(subscriptionId: String) = apply { this.subscriptionId = subscriptionId }
 
         /** A list of price intervals to add to the subscription. */
-        fun add(add: List<Add>?) = apply { body.add(add) }
+        fun add(add: List<Add>) = apply { body.add(add) }
 
         /** A list of price intervals to add to the subscription. */
-        fun add(add: Optional<List<Add>>) = add(add.orElse(null))
+        fun add(add: JsonField<List<Add>>) = apply { body.add(add) }
 
         /** A list of price intervals to add to the subscription. */
         fun addAdd(add: Add) = apply { body.addAdd(add) }
 
         /** A list of adjustments to add to the subscription. */
-        fun addAdjustments(addAdjustments: List<AddAdjustment>?) = apply {
+        fun addAdjustments(addAdjustments: List<AddAdjustment>) = apply {
             body.addAdjustments(addAdjustments)
         }
 
         /** A list of adjustments to add to the subscription. */
-        fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
-            addAdjustments(addAdjustments.orElse(null))
+        fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+            body.addAdjustments(addAdjustments)
+        }
 
         /** A list of adjustments to add to the subscription. */
         fun addAddAdjustment(addAdjustment: AddAdjustment) = apply {
@@ -278,28 +432,48 @@ constructor(
         }
 
         /** A list of price intervals to edit on the subscription. */
-        fun edit(edit: List<Edit>?) = apply { body.edit(edit) }
+        fun edit(edit: List<Edit>) = apply { body.edit(edit) }
 
         /** A list of price intervals to edit on the subscription. */
-        fun edit(edit: Optional<List<Edit>>) = edit(edit.orElse(null))
+        fun edit(edit: JsonField<List<Edit>>) = apply { body.edit(edit) }
 
         /** A list of price intervals to edit on the subscription. */
         fun addEdit(edit: Edit) = apply { body.addEdit(edit) }
 
         /** A list of adjustments to edit on the subscription. */
-        fun editAdjustments(editAdjustments: List<EditAdjustment>?) = apply {
+        fun editAdjustments(editAdjustments: List<EditAdjustment>) = apply {
             body.editAdjustments(editAdjustments)
         }
 
         /** A list of adjustments to edit on the subscription. */
-        fun editAdjustments(editAdjustments: Optional<List<EditAdjustment>>) =
-            editAdjustments(editAdjustments.orElse(null))
+        fun editAdjustments(editAdjustments: JsonField<List<EditAdjustment>>) = apply {
+            body.editAdjustments(editAdjustments)
+        }
 
         /** A list of adjustments to edit on the subscription. */
         fun addEditAdjustment(editAdjustment: EditAdjustment) = apply {
             body.addEditAdjustment(editAdjustment)
         }
 
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -398,25 +572,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionPriceIntervalsParams =
             SubscriptionPriceIntervalsParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
@@ -430,17 +585,37 @@ constructor(
     class Add
     @JsonCreator
     private constructor(
-        @JsonProperty("start_date") private val startDate: StartDate,
-        @JsonProperty("allocation_price") private val allocationPrice: AllocationPrice?,
-        @JsonProperty("discounts") private val discounts: List<Discount>?,
-        @JsonProperty("end_date") private val endDate: EndDate?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<StartDate> = JsonMissing.of(),
+        @JsonProperty("allocation_price")
+        @ExcludeMissing
+        private val allocationPrice: JsonField<AllocationPrice> = JsonMissing.of(),
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        private val discounts: JsonField<List<Discount>> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<EndDate> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
         @JsonProperty("fixed_fee_quantity_transitions")
-        private val fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?,
-        @JsonProperty("maximum_amount") private val maximumAmount: Double?,
-        @JsonProperty("minimum_amount") private val minimumAmount: Double?,
-        @JsonProperty("price") private val price: Price?,
-        @JsonProperty("price_id") private val priceId: String?,
+        @ExcludeMissing
+        private val fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
+            JsonMissing.of(),
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        private val maximumAmount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        private val minimumAmount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("price")
+        @ExcludeMissing
+        private val price: JsonField<Price> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -449,55 +624,131 @@ constructor(
          * The start date of the price interval. This is the date that the price will start billing
          * on the subscription.
          */
-        @JsonProperty("start_date") fun startDate(): StartDate = startDate
+        fun startDate(): StartDate = startDate.getRequired("start_date")
+
+        /** The definition of a new allocation price to create and add to the subscription. */
+        fun allocationPrice(): Optional<AllocationPrice> =
+            Optional.ofNullable(allocationPrice.getNullable("allocation_price"))
+
+        /** A list of discounts to initialize on the price interval. */
+        fun discounts(): Optional<List<Discount>> =
+            Optional.ofNullable(discounts.getNullable("discounts"))
+
+        /**
+         * The end date of the price interval. This is the date that the price will stop billing on
+         * the subscription.
+         */
+        fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The external price id of the price to add to the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** A list of fixed fee quantity transitions to initialize on the price interval. */
+        fun fixedFeeQuantityTransitions(): Optional<List<FixedFeeQuantityTransition>> =
+            Optional.ofNullable(
+                fixedFeeQuantityTransitions.getNullable("fixed_fee_quantity_transitions")
+            )
+
+        /**
+         * The maximum amount that will be billed for this price interval for a given billing
+         * period.
+         */
+        fun maximumAmount(): Optional<Double> =
+            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+        /**
+         * The minimum amount that will be billed for this price interval for a given billing
+         * period.
+         */
+        fun minimumAmount(): Optional<Double> =
+            Optional.ofNullable(minimumAmount.getNullable("minimum_amount"))
+
+        /** The definition of a new price to create and add to the subscription. */
+        fun price(): Optional<Price> = Optional.ofNullable(price.getNullable("price"))
+
+        /** The id of the price to add to the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
+        /**
+         * The start date of the price interval. This is the date that the price will start billing
+         * on the subscription.
+         */
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<StartDate> = startDate
 
         /** The definition of a new allocation price to create and add to the subscription. */
         @JsonProperty("allocation_price")
-        fun allocationPrice(): Optional<AllocationPrice> = Optional.ofNullable(allocationPrice)
+        @ExcludeMissing
+        fun _allocationPrice(): JsonField<AllocationPrice> = allocationPrice
 
         /** A list of discounts to initialize on the price interval. */
         @JsonProperty("discounts")
-        fun discounts(): Optional<List<Discount>> = Optional.ofNullable(discounts)
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         /**
          * The end date of the price interval. This is the date that the price will stop billing on
          * the subscription.
          */
-        @JsonProperty("end_date") fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate)
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<EndDate> = endDate
 
         /** The external price id of the price to add to the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** A list of fixed fee quantity transitions to initialize on the price interval. */
         @JsonProperty("fixed_fee_quantity_transitions")
-        fun fixedFeeQuantityTransitions(): Optional<List<FixedFeeQuantityTransition>> =
-            Optional.ofNullable(fixedFeeQuantityTransitions)
+        @ExcludeMissing
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The maximum amount that will be billed for this price interval for a given billing
          * period.
          */
         @JsonProperty("maximum_amount")
-        fun maximumAmount(): Optional<Double> = Optional.ofNullable(maximumAmount)
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<Double> = maximumAmount
 
         /**
          * The minimum amount that will be billed for this price interval for a given billing
          * period.
          */
         @JsonProperty("minimum_amount")
-        fun minimumAmount(): Optional<Double> = Optional.ofNullable(minimumAmount)
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<Double> = minimumAmount
 
         /** The definition of a new price to create and add to the subscription. */
-        @JsonProperty("price") fun price(): Optional<Price> = Optional.ofNullable(price)
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /** The id of the price to add to the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Add = apply {
+            if (!validated) {
+                startDate()
+                allocationPrice().map { it.validate() }
+                discounts()
+                endDate()
+                externalPriceId()
+                fixedFeeQuantityTransitions().map { it.forEach { it.validate() } }
+                maximumAmount()
+                minimumAmount()
+                price()
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -507,26 +758,29 @@ constructor(
 
         class Builder {
 
-            private var startDate: StartDate? = null
-            private var allocationPrice: AllocationPrice? = null
-            private var discounts: MutableList<Discount>? = null
-            private var endDate: EndDate? = null
-            private var externalPriceId: String? = null
-            private var fixedFeeQuantityTransitions: MutableList<FixedFeeQuantityTransition>? = null
-            private var maximumAmount: Double? = null
-            private var minimumAmount: Double? = null
-            private var price: Price? = null
-            private var priceId: String? = null
+            private var startDate: JsonField<StartDate>? = null
+            private var allocationPrice: JsonField<AllocationPrice> = JsonMissing.of()
+            private var discounts: JsonField<MutableList<Discount>>? = null
+            private var endDate: JsonField<EndDate> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var maximumAmount: JsonField<Double> = JsonMissing.of()
+            private var minimumAmount: JsonField<Double> = JsonMissing.of()
+            private var price: JsonField<Price> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(add: Add) = apply {
                 startDate = add.startDate
                 allocationPrice = add.allocationPrice
-                discounts = add.discounts?.toMutableList()
+                discounts = add.discounts.map { it.toMutableList() }
                 endDate = add.endDate
                 externalPriceId = add.externalPriceId
-                fixedFeeQuantityTransitions = add.fixedFeeQuantityTransitions?.toMutableList()
+                fixedFeeQuantityTransitions =
+                    add.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 maximumAmount = add.maximumAmount
                 minimumAmount = add.minimumAmount
                 price = add.price
@@ -538,43 +792,62 @@ constructor(
              * The start date of the price interval. This is the date that the price will start
              * billing on the subscription.
              */
-            fun startDate(startDate: StartDate) = apply { this.startDate = startDate }
+            fun startDate(startDate: StartDate) = startDate(JsonField.of(startDate))
 
-            fun startDate(dateTime: OffsetDateTime) = apply {
-                this.startDate = StartDate.ofDateTime(dateTime)
-            }
+            /**
+             * The start date of the price interval. This is the date that the price will start
+             * billing on the subscription.
+             */
+            fun startDate(startDate: JsonField<StartDate>) = apply { this.startDate = startDate }
 
-            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.startDate = StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun startDate(dateTime: OffsetDateTime) = startDate(StartDate.ofDateTime(dateTime))
+
+            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                startDate(StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             /** The definition of a new allocation price to create and add to the subscription. */
-            fun allocationPrice(allocationPrice: AllocationPrice?) = apply {
-                this.allocationPrice = allocationPrice
-            }
+            fun allocationPrice(allocationPrice: AllocationPrice?) =
+                allocationPrice(JsonField.ofNullable(allocationPrice))
 
             /** The definition of a new allocation price to create and add to the subscription. */
             fun allocationPrice(allocationPrice: Optional<AllocationPrice>) =
                 allocationPrice(allocationPrice.orElse(null))
 
-            /** A list of discounts to initialize on the price interval. */
-            fun discounts(discounts: List<Discount>?) = apply {
-                this.discounts = discounts?.toMutableList()
+            /** The definition of a new allocation price to create and add to the subscription. */
+            fun allocationPrice(allocationPrice: JsonField<AllocationPrice>) = apply {
+                this.allocationPrice = allocationPrice
             }
 
+            /** A list of discounts to initialize on the price interval. */
+            fun discounts(discounts: List<Discount>?) = discounts(JsonField.ofNullable(discounts))
+
             /** A list of discounts to initialize on the price interval. */
             fun discounts(discounts: Optional<List<Discount>>) = discounts(discounts.orElse(null))
 
+            /** A list of discounts to initialize on the price interval. */
+            fun discounts(discounts: JsonField<List<Discount>>) = apply {
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
             /** A list of discounts to initialize on the price interval. */
             fun addDiscount(discount: Discount) = apply {
-                discounts = (discounts ?: mutableListOf()).apply { add(discount) }
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
              * on the subscription.
              */
-            fun endDate(endDate: EndDate?) = apply { this.endDate = endDate }
+            fun endDate(endDate: EndDate?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
@@ -582,42 +855,61 @@ constructor(
              */
             fun endDate(endDate: Optional<EndDate>) = endDate(endDate.orElse(null))
 
-            fun endDate(dateTime: OffsetDateTime) = apply {
-                this.endDate = EndDate.ofDateTime(dateTime)
-            }
+            /**
+             * The end date of the price interval. This is the date that the price will stop billing
+             * on the subscription.
+             */
+            fun endDate(endDate: JsonField<EndDate>) = apply { this.endDate = endDate }
 
-            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.endDate = EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun endDate(dateTime: OffsetDateTime) = endDate(EndDate.ofDateTime(dateTime))
+
+            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                endDate(EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             /** The external price id of the price to add to the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to add to the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** The external price id of the price to add to the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /** A list of fixed fee quantity transitions to initialize on the price interval. */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
-            ) = apply {
-                this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions?.toMutableList()
-            }
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
 
             /** A list of fixed fee quantity transitions to initialize on the price interval. */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
             ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
+            /** A list of fixed fee quantity transitions to initialize on the price interval. */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
             /** A list of fixed fee quantity transitions to initialize on the price interval. */
             fun addFixedFeeQuantityTransition(
                 fixedFeeQuantityTransition: FixedFeeQuantityTransition
             ) = apply {
                 fixedFeeQuantityTransitions =
-                    (fixedFeeQuantityTransitions ?: mutableListOf()).apply {
-                        add(fixedFeeQuantityTransition)
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
                     }
             }
 
@@ -625,7 +917,8 @@ constructor(
              * The maximum amount that will be billed for this price interval for a given billing
              * period.
              */
-            fun maximumAmount(maximumAmount: Double?) = apply { this.maximumAmount = maximumAmount }
+            fun maximumAmount(maximumAmount: Double?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
 
             /**
              * The maximum amount that will be billed for this price interval for a given billing
@@ -641,11 +934,20 @@ constructor(
             fun maximumAmount(maximumAmount: Optional<Double>) =
                 maximumAmount(maximumAmount.orElse(null) as Double?)
 
+            /**
+             * The maximum amount that will be billed for this price interval for a given billing
+             * period.
+             */
+            fun maximumAmount(maximumAmount: JsonField<Double>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
             /**
              * The minimum amount that will be billed for this price interval for a given billing
              * period.
              */
-            fun minimumAmount(minimumAmount: Double?) = apply { this.minimumAmount = minimumAmount }
+            fun minimumAmount(minimumAmount: Double?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
 
             /**
              * The minimum amount that will be billed for this price interval for a given billing
@@ -661,170 +963,159 @@ constructor(
             fun minimumAmount(minimumAmount: Optional<Double>) =
                 minimumAmount(minimumAmount.orElse(null) as Double?)
 
+            /**
+             * The minimum amount that will be billed for this price interval for a given billing
+             * period.
+             */
+            fun minimumAmount(minimumAmount: JsonField<Double>) = apply {
+                this.minimumAmount = minimumAmount
+            }
+
             /** The definition of a new price to create and add to the subscription. */
-            fun price(price: Price?) = apply { this.price = price }
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /** The definition of a new price to create and add to the subscription. */
             fun price(price: Optional<Price>) = price(price.orElse(null))
 
-            fun price(newFloatingUnitPrice: Price.NewFloatingUnitPrice) = apply {
-                this.price = Price.ofNewFloatingUnitPrice(newFloatingUnitPrice)
-            }
+            /** The definition of a new price to create and add to the subscription. */
+            fun price(price: JsonField<Price>) = apply { this.price = price }
 
-            fun price(newFloatingPackagePrice: Price.NewFloatingPackagePrice) = apply {
-                this.price = Price.ofNewFloatingPackagePrice(newFloatingPackagePrice)
-            }
+            fun price(newFloatingUnitPrice: Price.NewFloatingUnitPrice) =
+                price(Price.ofNewFloatingUnitPrice(newFloatingUnitPrice))
 
-            fun price(newFloatingMatrixPrice: Price.NewFloatingMatrixPrice) = apply {
-                this.price = Price.ofNewFloatingMatrixPrice(newFloatingMatrixPrice)
-            }
+            fun price(newFloatingPackagePrice: Price.NewFloatingPackagePrice) =
+                price(Price.ofNewFloatingPackagePrice(newFloatingPackagePrice))
+
+            fun price(newFloatingMatrixPrice: Price.NewFloatingMatrixPrice) =
+                price(Price.ofNewFloatingMatrixPrice(newFloatingMatrixPrice))
 
             fun price(
                 newFloatingMatrixWithAllocationPrice: Price.NewFloatingMatrixWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingMatrixWithAllocationPrice(
                         newFloatingMatrixWithAllocationPrice
                     )
-            }
+                )
 
-            fun price(newFloatingTieredPrice: Price.NewFloatingTieredPrice) = apply {
-                this.price = Price.ofNewFloatingTieredPrice(newFloatingTieredPrice)
-            }
+            fun price(newFloatingTieredPrice: Price.NewFloatingTieredPrice) =
+                price(Price.ofNewFloatingTieredPrice(newFloatingTieredPrice))
 
-            fun price(newFloatingTieredBpsPrice: Price.NewFloatingTieredBpsPrice) = apply {
-                this.price = Price.ofNewFloatingTieredBpsPrice(newFloatingTieredBpsPrice)
-            }
+            fun price(newFloatingTieredBpsPrice: Price.NewFloatingTieredBpsPrice) =
+                price(Price.ofNewFloatingTieredBpsPrice(newFloatingTieredBpsPrice))
 
-            fun price(newFloatingBpsPrice: Price.NewFloatingBpsPrice) = apply {
-                this.price = Price.ofNewFloatingBpsPrice(newFloatingBpsPrice)
-            }
+            fun price(newFloatingBpsPrice: Price.NewFloatingBpsPrice) =
+                price(Price.ofNewFloatingBpsPrice(newFloatingBpsPrice))
 
-            fun price(newFloatingBulkBpsPrice: Price.NewFloatingBulkBpsPrice) = apply {
-                this.price = Price.ofNewFloatingBulkBpsPrice(newFloatingBulkBpsPrice)
-            }
+            fun price(newFloatingBulkBpsPrice: Price.NewFloatingBulkBpsPrice) =
+                price(Price.ofNewFloatingBulkBpsPrice(newFloatingBulkBpsPrice))
 
-            fun price(newFloatingBulkPrice: Price.NewFloatingBulkPrice) = apply {
-                this.price = Price.ofNewFloatingBulkPrice(newFloatingBulkPrice)
-            }
+            fun price(newFloatingBulkPrice: Price.NewFloatingBulkPrice) =
+                price(Price.ofNewFloatingBulkPrice(newFloatingBulkPrice))
 
             fun price(
                 newFloatingThresholdTotalAmountPrice: Price.NewFloatingThresholdTotalAmountPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingThresholdTotalAmountPrice(
                         newFloatingThresholdTotalAmountPrice
                     )
-            }
+                )
 
-            fun price(newFloatingTieredPackagePrice: Price.NewFloatingTieredPackagePrice) = apply {
-                this.price = Price.ofNewFloatingTieredPackagePrice(newFloatingTieredPackagePrice)
-            }
+            fun price(newFloatingTieredPackagePrice: Price.NewFloatingTieredPackagePrice) =
+                price(Price.ofNewFloatingTieredPackagePrice(newFloatingTieredPackagePrice))
 
-            fun price(newFloatingGroupedTieredPrice: Price.NewFloatingGroupedTieredPrice) = apply {
-                this.price = Price.ofNewFloatingGroupedTieredPrice(newFloatingGroupedTieredPrice)
-            }
+            fun price(newFloatingGroupedTieredPrice: Price.NewFloatingGroupedTieredPrice) =
+                price(Price.ofNewFloatingGroupedTieredPrice(newFloatingGroupedTieredPrice))
 
             fun price(newFloatingTieredWithMinimumPrice: Price.NewFloatingTieredWithMinimumPrice) =
-                apply {
-                    this.price =
-                        Price.ofNewFloatingTieredWithMinimumPrice(newFloatingTieredWithMinimumPrice)
-                }
+                price(Price.ofNewFloatingTieredWithMinimumPrice(newFloatingTieredWithMinimumPrice))
 
             fun price(
                 newFloatingPackageWithAllocationPrice: Price.NewFloatingPackageWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingPackageWithAllocationPrice(
                         newFloatingPackageWithAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newFloatingTieredPackageWithMinimumPrice:
                     Price.NewFloatingTieredPackageWithMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingTieredPackageWithMinimumPrice(
                         newFloatingTieredPackageWithMinimumPrice
                     )
-            }
+                )
 
             fun price(newFloatingUnitWithPercentPrice: Price.NewFloatingUnitWithPercentPrice) =
-                apply {
-                    this.price =
-                        Price.ofNewFloatingUnitWithPercentPrice(newFloatingUnitWithPercentPrice)
-                }
+                price(Price.ofNewFloatingUnitWithPercentPrice(newFloatingUnitWithPercentPrice))
 
             fun price(
                 newFloatingTieredWithProrationPrice: Price.NewFloatingTieredWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingTieredWithProrationPrice(newFloatingTieredWithProrationPrice)
-            }
+                )
 
             fun price(newFloatingUnitWithProrationPrice: Price.NewFloatingUnitWithProrationPrice) =
-                apply {
-                    this.price =
-                        Price.ofNewFloatingUnitWithProrationPrice(newFloatingUnitWithProrationPrice)
-                }
+                price(Price.ofNewFloatingUnitWithProrationPrice(newFloatingUnitWithProrationPrice))
 
             fun price(newFloatingGroupedAllocationPrice: Price.NewFloatingGroupedAllocationPrice) =
-                apply {
-                    this.price =
-                        Price.ofNewFloatingGroupedAllocationPrice(newFloatingGroupedAllocationPrice)
-                }
+                price(Price.ofNewFloatingGroupedAllocationPrice(newFloatingGroupedAllocationPrice))
 
             fun price(
                 newFloatingGroupedWithProratedMinimumPrice:
                     Price.NewFloatingGroupedWithProratedMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingGroupedWithProratedMinimumPrice(
                         newFloatingGroupedWithProratedMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newFloatingGroupedWithMeteredMinimumPrice:
                     Price.NewFloatingGroupedWithMeteredMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingGroupedWithMeteredMinimumPrice(
                         newFloatingGroupedWithMeteredMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newFloatingMatrixWithDisplayNamePrice: Price.NewFloatingMatrixWithDisplayNamePrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingMatrixWithDisplayNamePrice(
                         newFloatingMatrixWithDisplayNamePrice
                     )
-            }
+                )
 
             fun price(newFloatingBulkWithProrationPrice: Price.NewFloatingBulkWithProrationPrice) =
-                apply {
-                    this.price =
-                        Price.ofNewFloatingBulkWithProrationPrice(newFloatingBulkWithProrationPrice)
-                }
+                price(Price.ofNewFloatingBulkWithProrationPrice(newFloatingBulkWithProrationPrice))
 
             fun price(
                 newFloatingGroupedTieredPackagePrice: Price.NewFloatingGroupedTieredPackagePrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewFloatingGroupedTieredPackagePrice(
                         newFloatingGroupedTieredPackagePrice
                     )
-            }
+                )
 
             /** The id of the price to add to the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to add to the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to add to the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -848,10 +1139,10 @@ constructor(
                 Add(
                     checkNotNull(startDate) { "`startDate` is required but was not set" },
                     allocationPrice,
-                    discounts?.toImmutable(),
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     endDate,
                     externalPriceId,
-                    fixedFeeQuantityTransitions?.toImmutable(),
+                    (fixedFeeQuantityTransitions ?: JsonMissing.of()).map { it.toImmutable() },
                     maximumAmount,
                     minimumAmount,
                     price,
@@ -873,6 +1164,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -898,6 +1191,15 @@ constructor(
                 }
             }
 
+            fun validate(): StartDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown StartDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -978,37 +1280,77 @@ constructor(
         class AllocationPrice
         @JsonCreator
         private constructor(
-            @JsonProperty("amount") private val amount: String,
-            @JsonProperty("cadence") private val cadence: Cadence,
-            @JsonProperty("currency") private val currency: String,
-            @JsonProperty("expires_at_end_of_cadence") private val expiresAtEndOfCadence: Boolean,
+            @JsonProperty("amount")
+            @ExcludeMissing
+            private val amount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("cadence")
+            @ExcludeMissing
+            private val cadence: JsonField<Cadence> = JsonMissing.of(),
+            @JsonProperty("currency")
+            @ExcludeMissing
+            private val currency: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("expires_at_end_of_cadence")
+            @ExcludeMissing
+            private val expiresAtEndOfCadence: JsonField<Boolean> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** An amount of the currency to allocate to the customer at the specified cadence. */
-            @JsonProperty("amount") fun amount(): String = amount
+            fun amount(): String = amount.getRequired("amount")
+
+            /** The cadence at which to allocate the amount to the customer. */
+            fun cadence(): Cadence = cadence.getRequired("cadence")
+
+            /**
+             * An ISO 4217 currency string or a custom pricing unit identifier in which to bill this
+             * price.
+             */
+            fun currency(): String = currency.getRequired("currency")
+
+            /**
+             * Whether the allocated amount should expire at the end of the cadence or roll over to
+             * the next period.
+             */
+            fun expiresAtEndOfCadence(): Boolean =
+                expiresAtEndOfCadence.getRequired("expires_at_end_of_cadence")
+
+            /** An amount of the currency to allocate to the customer at the specified cadence. */
+            @JsonProperty("amount") @ExcludeMissing fun _amount(): JsonField<String> = amount
 
             /** The cadence at which to allocate the amount to the customer. */
-            @JsonProperty("cadence") fun cadence(): Cadence = cadence
+            @JsonProperty("cadence") @ExcludeMissing fun _cadence(): JsonField<Cadence> = cadence
 
             /**
              * An ISO 4217 currency string or a custom pricing unit identifier in which to bill this
              * price.
              */
-            @JsonProperty("currency") fun currency(): String = currency
+            @JsonProperty("currency") @ExcludeMissing fun _currency(): JsonField<String> = currency
 
             /**
              * Whether the allocated amount should expire at the end of the cadence or roll over to
              * the next period.
              */
             @JsonProperty("expires_at_end_of_cadence")
-            fun expiresAtEndOfCadence(): Boolean = expiresAtEndOfCadence
+            @ExcludeMissing
+            fun _expiresAtEndOfCadence(): JsonField<Boolean> = expiresAtEndOfCadence
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): AllocationPrice = apply {
+                if (!validated) {
+                    amount()
+                    cadence()
+                    currency()
+                    expiresAtEndOfCadence()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1018,10 +1360,10 @@ constructor(
 
             class Builder {
 
-                private var amount: String? = null
-                private var cadence: Cadence? = null
-                private var currency: String? = null
-                private var expiresAtEndOfCadence: Boolean? = null
+                private var amount: JsonField<String>? = null
+                private var cadence: JsonField<Cadence>? = null
+                private var currency: JsonField<String>? = null
+                private var expiresAtEndOfCadence: JsonField<Boolean>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1036,22 +1378,43 @@ constructor(
                 /**
                  * An amount of the currency to allocate to the customer at the specified cadence.
                  */
-                fun amount(amount: String) = apply { this.amount = amount }
+                fun amount(amount: String) = amount(JsonField.of(amount))
+
+                /**
+                 * An amount of the currency to allocate to the customer at the specified cadence.
+                 */
+                fun amount(amount: JsonField<String>) = apply { this.amount = amount }
+
+                /** The cadence at which to allocate the amount to the customer. */
+                fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                 /** The cadence at which to allocate the amount to the customer. */
-                fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                 /**
                  * An ISO 4217 currency string or a custom pricing unit identifier in which to bill
                  * this price.
                  */
-                fun currency(currency: String) = apply { this.currency = currency }
+                fun currency(currency: String) = currency(JsonField.of(currency))
+
+                /**
+                 * An ISO 4217 currency string or a custom pricing unit identifier in which to bill
+                 * this price.
+                 */
+                fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                /**
+                 * Whether the allocated amount should expire at the end of the cadence or roll over
+                 * to the next period.
+                 */
+                fun expiresAtEndOfCadence(expiresAtEndOfCadence: Boolean) =
+                    expiresAtEndOfCadence(JsonField.of(expiresAtEndOfCadence))
 
                 /**
                  * Whether the allocated amount should expire at the end of the cadence or roll over
                  * to the next period.
                  */
-                fun expiresAtEndOfCadence(expiresAtEndOfCadence: Boolean) = apply {
+                fun expiresAtEndOfCadence(expiresAtEndOfCadence: JsonField<Boolean>) = apply {
                     this.expiresAtEndOfCadence = expiresAtEndOfCadence
                 }
 
@@ -1198,6 +1561,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun amountDiscountCreationParams(): Optional<AmountDiscountCreationParams> =
                 Optional.ofNullable(amountDiscountCreationParams)
 
@@ -1239,6 +1604,22 @@ constructor(
                 }
             }
 
+            fun validate(): Discount = apply {
+                if (!validated) {
+                    if (
+                        amountDiscountCreationParams == null &&
+                            percentageDiscountCreationParams == null &&
+                            usageDiscountCreationParams == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Discount: $_json")
+                    }
+                    amountDiscountCreationParams?.validate()
+                    percentageDiscountCreationParams?.validate()
+                    usageDiscountCreationParams?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -1307,13 +1688,20 @@ constructor(
 
                     when (discountType) {
                         "amount" -> {
-                            tryDeserialize(node, jacksonTypeRef<AmountDiscountCreationParams>())
+                            tryDeserialize(node, jacksonTypeRef<AmountDiscountCreationParams>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Discount(amountDiscountCreationParams = it, _json = json)
                                 }
                         }
                         "percentage" -> {
-                            tryDeserialize(node, jacksonTypeRef<PercentageDiscountCreationParams>())
+                            tryDeserialize(
+                                    node,
+                                    jacksonTypeRef<PercentageDiscountCreationParams>()
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Discount(
                                         percentageDiscountCreationParams = it,
@@ -1322,7 +1710,9 @@ constructor(
                                 }
                         }
                         "usage" -> {
-                            tryDeserialize(node, jacksonTypeRef<UsageDiscountCreationParams>())
+                            tryDeserialize(node, jacksonTypeRef<UsageDiscountCreationParams>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Discount(usageDiscountCreationParams = it, _json = json)
                                 }
@@ -1357,21 +1747,44 @@ constructor(
             class AmountDiscountCreationParams
             @JsonCreator
             private constructor(
-                @JsonProperty("amount_discount") private val amountDiscount: Double,
-                @JsonProperty("discount_type") private val discountType: DiscountType,
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                private val discountType: JsonField<DiscountType> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** Only available if discount_type is `amount`. */
-                @JsonProperty("amount_discount") fun amountDiscount(): Double = amountDiscount
+                fun amountDiscount(): Double = amountDiscount.getRequired("amount_discount")
+
+                fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+                /** Only available if discount_type is `amount`. */
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<Double> = amountDiscount
 
-                @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                fun _discountType(): JsonField<DiscountType> = discountType
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): AmountDiscountCreationParams = apply {
+                    if (!validated) {
+                        amountDiscount()
+                        discountType()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1381,8 +1794,8 @@ constructor(
 
                 class Builder {
 
-                    private var amountDiscount: Double? = null
-                    private var discountType: DiscountType? = null
+                    private var amountDiscount: JsonField<Double>? = null
+                    private var discountType: JsonField<DiscountType>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1395,11 +1808,18 @@ constructor(
                         }
 
                     /** Only available if discount_type is `amount`. */
-                    fun amountDiscount(amountDiscount: Double) = apply {
+                    fun amountDiscount(amountDiscount: Double) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    /** Only available if discount_type is `amount`. */
+                    fun amountDiscount(amountDiscount: JsonField<Double>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
-                    fun discountType(discountType: DiscountType) = apply {
+                    fun discountType(discountType: DiscountType) =
+                        discountType(JsonField.of(discountType))
+
+                    fun discountType(discountType: JsonField<DiscountType>) = apply {
                         this.discountType = discountType
                     }
 
@@ -1511,25 +1931,51 @@ constructor(
             class PercentageDiscountCreationParams
             @JsonCreator
             private constructor(
-                @JsonProperty("discount_type") private val discountType: DiscountType,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+                fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+                /**
+                 * Only available if discount_type is `percentage`. This is a number between 0
+                 * and 1.
+                 */
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                fun _discountType(): JsonField<DiscountType> = discountType
 
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
                  * and 1.
                  */
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): PercentageDiscountCreationParams = apply {
+                    if (!validated) {
+                        discountType()
+                        percentageDiscount()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1539,8 +1985,8 @@ constructor(
 
                 class Builder {
 
-                    private var discountType: DiscountType? = null
-                    private var percentageDiscount: Double? = null
+                    private var discountType: JsonField<DiscountType>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1553,7 +1999,10 @@ constructor(
                             percentageDiscountCreationParams.additionalProperties.toMutableMap()
                     }
 
-                    fun discountType(discountType: DiscountType) = apply {
+                    fun discountType(discountType: DiscountType) =
+                        discountType(JsonField.of(discountType))
+
+                    fun discountType(discountType: JsonField<DiscountType>) = apply {
                         this.discountType = discountType
                     }
 
@@ -1561,7 +2010,14 @@ constructor(
                      * Only available if discount_type is `percentage`. This is a number between 0
                      * and 1.
                      */
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
+
+                    /**
+                     * Only available if discount_type is `percentage`. This is a number between 0
+                     * and 1.
+                     */
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
                         this.percentageDiscount = percentageDiscount
                     }
 
@@ -1673,24 +2129,50 @@ constructor(
             class UsageDiscountCreationParams
             @JsonCreator
             private constructor(
-                @JsonProperty("discount_type") private val discountType: DiscountType,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+                fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+                /**
+                 * Only available if discount_type is `usage`. Number of usage units that this
+                 * discount is for.
+                 */
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                @JsonProperty("discount_type")
+                @ExcludeMissing
+                fun _discountType(): JsonField<DiscountType> = discountType
 
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
                  * discount is for.
                  */
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): UsageDiscountCreationParams = apply {
+                    if (!validated) {
+                        discountType()
+                        usageDiscount()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -1700,8 +2182,8 @@ constructor(
 
                 class Builder {
 
-                    private var discountType: DiscountType? = null
-                    private var usageDiscount: Double? = null
+                    private var discountType: JsonField<DiscountType>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1713,7 +2195,10 @@ constructor(
                                 usageDiscountCreationParams.additionalProperties.toMutableMap()
                         }
 
-                    fun discountType(discountType: DiscountType) = apply {
+                    fun discountType(discountType: DiscountType) =
+                        discountType(JsonField.of(discountType))
+
+                    fun discountType(discountType: JsonField<DiscountType>) = apply {
                         this.discountType = discountType
                     }
 
@@ -1721,7 +2206,14 @@ constructor(
                      * Only available if discount_type is `usage`. Number of usage units that this
                      * discount is for.
                      */
-                    fun usageDiscount(usageDiscount: Double) = apply {
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
+
+                    /**
+                     * Only available if discount_type is `usage`. Number of usage units that this
+                     * discount is for.
+                     */
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
                         this.usageDiscount = usageDiscount
                     }
 
@@ -1843,6 +2335,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -1868,6 +2362,15 @@ constructor(
                 }
             }
 
+            fun validate(): EndDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown EndDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -1947,22 +2450,44 @@ constructor(
         class FixedFeeQuantityTransition
         @JsonCreator
         private constructor(
-            @JsonProperty("effective_date") private val effectiveDate: OffsetDateTime,
-            @JsonProperty("quantity") private val quantity: Long,
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            private val effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+            @JsonProperty("quantity")
+            @ExcludeMissing
+            private val quantity: JsonField<Long> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The date that the fixed fee quantity transition should take effect. */
-            @JsonProperty("effective_date") fun effectiveDate(): OffsetDateTime = effectiveDate
+            fun effectiveDate(): OffsetDateTime = effectiveDate.getRequired("effective_date")
+
+            /** The quantity of the fixed fee quantity transition. */
+            fun quantity(): Long = quantity.getRequired("quantity")
+
+            /** The date that the fixed fee quantity transition should take effect. */
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
             /** The quantity of the fixed fee quantity transition. */
-            @JsonProperty("quantity") fun quantity(): Long = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): FixedFeeQuantityTransition = apply {
+                if (!validated) {
+                    effectiveDate()
+                    quantity()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -1972,8 +2497,8 @@ constructor(
 
             class Builder {
 
-                private var effectiveDate: OffsetDateTime? = null
-                private var quantity: Long? = null
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -1985,12 +2510,19 @@ constructor(
                 }
 
                 /** The date that the fixed fee quantity transition should take effect. */
-                fun effectiveDate(effectiveDate: OffsetDateTime) = apply {
+                fun effectiveDate(effectiveDate: OffsetDateTime) =
+                    effectiveDate(JsonField.of(effectiveDate))
+
+                /** The date that the fixed fee quantity transition should take effect. */
+                fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
                     this.effectiveDate = effectiveDate
                 }
 
                 /** The quantity of the fixed fee quantity transition. */
-                fun quantity(quantity: Long) = apply { this.quantity = quantity }
+                fun quantity(quantity: Long) = quantity(JsonField.of(quantity))
+
+                /** The quantity of the fixed fee quantity transition. */
+                fun quantity(quantity: JsonField<Long>) = apply { this.quantity = quantity }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -2095,6 +2627,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newFloatingUnitPrice(): Optional<NewFloatingUnitPrice> =
                 Optional.ofNullable(newFloatingUnitPrice)
 
@@ -2415,6 +2949,64 @@ constructor(
                 }
             }
 
+            fun validate(): Price = apply {
+                if (!validated) {
+                    if (
+                        newFloatingUnitPrice == null &&
+                            newFloatingPackagePrice == null &&
+                            newFloatingMatrixPrice == null &&
+                            newFloatingMatrixWithAllocationPrice == null &&
+                            newFloatingTieredPrice == null &&
+                            newFloatingTieredBpsPrice == null &&
+                            newFloatingBpsPrice == null &&
+                            newFloatingBulkBpsPrice == null &&
+                            newFloatingBulkPrice == null &&
+                            newFloatingThresholdTotalAmountPrice == null &&
+                            newFloatingTieredPackagePrice == null &&
+                            newFloatingGroupedTieredPrice == null &&
+                            newFloatingTieredWithMinimumPrice == null &&
+                            newFloatingPackageWithAllocationPrice == null &&
+                            newFloatingTieredPackageWithMinimumPrice == null &&
+                            newFloatingUnitWithPercentPrice == null &&
+                            newFloatingTieredWithProrationPrice == null &&
+                            newFloatingUnitWithProrationPrice == null &&
+                            newFloatingGroupedAllocationPrice == null &&
+                            newFloatingGroupedWithProratedMinimumPrice == null &&
+                            newFloatingGroupedWithMeteredMinimumPrice == null &&
+                            newFloatingMatrixWithDisplayNamePrice == null &&
+                            newFloatingBulkWithProrationPrice == null &&
+                            newFloatingGroupedTieredPackagePrice == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Price: $_json")
+                    }
+                    newFloatingUnitPrice?.validate()
+                    newFloatingPackagePrice?.validate()
+                    newFloatingMatrixPrice?.validate()
+                    newFloatingMatrixWithAllocationPrice?.validate()
+                    newFloatingTieredPrice?.validate()
+                    newFloatingTieredBpsPrice?.validate()
+                    newFloatingBpsPrice?.validate()
+                    newFloatingBulkBpsPrice?.validate()
+                    newFloatingBulkPrice?.validate()
+                    newFloatingThresholdTotalAmountPrice?.validate()
+                    newFloatingTieredPackagePrice?.validate()
+                    newFloatingGroupedTieredPrice?.validate()
+                    newFloatingTieredWithMinimumPrice?.validate()
+                    newFloatingPackageWithAllocationPrice?.validate()
+                    newFloatingTieredPackageWithMinimumPrice?.validate()
+                    newFloatingUnitWithPercentPrice?.validate()
+                    newFloatingTieredWithProrationPrice?.validate()
+                    newFloatingUnitWithProrationPrice?.validate()
+                    newFloatingGroupedAllocationPrice?.validate()
+                    newFloatingGroupedWithProratedMinimumPrice?.validate()
+                    newFloatingGroupedWithMeteredMinimumPrice?.validate()
+                    newFloatingMatrixWithDisplayNamePrice?.validate()
+                    newFloatingBulkWithProrationPrice?.validate()
+                    newFloatingGroupedTieredPackagePrice?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -2731,25 +3323,36 @@ constructor(
 
                     when (modelType) {
                         "unit" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingUnitPrice>())?.let {
-                                return Price(newFloatingUnitPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingUnitPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingUnitPrice = it, _json = json)
+                                }
                         }
                         "package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingPackagePrice>())?.let {
-                                return Price(newFloatingPackagePrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingPackagePrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingPackagePrice = it, _json = json)
+                                }
                         }
                         "matrix" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingMatrixPrice>())?.let {
-                                return Price(newFloatingMatrixPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingMatrixPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingMatrixPrice = it, _json = json)
+                                }
                         }
                         "matrix_with_allocation" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingMatrixWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingMatrixWithAllocationPrice = it,
@@ -2758,35 +3361,52 @@ constructor(
                                 }
                         }
                         "tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredPrice>())?.let {
-                                return Price(newFloatingTieredPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingTieredPrice = it, _json = json)
+                                }
                         }
                         "tiered_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredBpsPrice>())?.let {
-                                return Price(newFloatingTieredBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingTieredBpsPrice = it, _json = json)
+                                }
                         }
                         "bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingBpsPrice>())?.let {
-                                return Price(newFloatingBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingBulkBpsPrice>())?.let {
-                                return Price(newFloatingBulkBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingBulkBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingBulkBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingBulkPrice>())?.let {
-                                return Price(newFloatingBulkPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingBulkPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newFloatingBulkPrice = it, _json = json)
+                                }
                         }
                         "threshold_total_amount" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingThresholdTotalAmountPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingThresholdTotalAmountPrice = it,
@@ -2795,13 +3415,17 @@ constructor(
                                 }
                         }
                         "tiered_package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredPackagePrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingTieredPackagePrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newFloatingTieredPackagePrice = it, _json = json)
                                 }
                         }
                         "grouped_tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingGroupedTieredPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewFloatingGroupedTieredPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newFloatingGroupedTieredPrice = it, _json = json)
                                 }
@@ -2810,7 +3434,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingTieredWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingTieredWithMinimumPrice = it,
@@ -2822,7 +3448,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingPackageWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingPackageWithAllocationPrice = it,
@@ -2834,7 +3462,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingTieredPackageWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingTieredPackageWithMinimumPrice = it,
@@ -2843,7 +3473,12 @@ constructor(
                                 }
                         }
                         "unit_with_percent" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewFloatingUnitWithPercentPrice>())
+                            tryDeserialize(
+                                    node,
+                                    jacksonTypeRef<NewFloatingUnitWithPercentPrice>()
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newFloatingUnitWithPercentPrice = it, _json = json)
                                 }
@@ -2852,7 +3487,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingTieredWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingTieredWithProrationPrice = it,
@@ -2864,7 +3501,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingUnitWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingUnitWithProrationPrice = it,
@@ -2876,7 +3515,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingGroupedAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingGroupedAllocationPrice = it,
@@ -2888,7 +3529,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingGroupedWithProratedMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingGroupedWithProratedMinimumPrice = it,
@@ -2900,7 +3543,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingGroupedWithMeteredMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingGroupedWithMeteredMinimumPrice = it,
@@ -2912,7 +3557,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingMatrixWithDisplayNamePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingMatrixWithDisplayNamePrice = it,
@@ -2924,7 +3571,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingBulkWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingBulkWithProrationPrice = it,
@@ -2936,7 +3585,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewFloatingGroupedTieredPackagePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newFloatingGroupedTieredPackagePrice = it,
@@ -3012,95 +3663,216 @@ constructor(
                 }
             }
 
-            @NoAutoDetect
-            class NewFloatingUnitPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+            @NoAutoDetect
+            class NewFloatingUnitPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -3108,12 +3880,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingUnitPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        unitConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -3123,21 +3919,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitConfig: UnitConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitConfig: JsonField<UnitConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -3163,28 +3962,47 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
 
-                    fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                    fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                        this.unitConfig = unitConfig
+                    }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -3193,13 +4011,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -3216,13 +4041,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -3232,12 +4065,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -3252,22 +4092,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -3284,22 +4134,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -3309,12 +4174,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -3323,6 +4196,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -3504,18 +4384,34 @@ constructor(
                 class UnitConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Rate per unit of usage */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Rate per unit of usage */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitConfig = apply {
+                        if (!validated) {
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -3525,7 +4421,7 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -3536,7 +4432,12 @@ constructor(
                         }
 
                         /** Rate per unit of usage */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Rate per unit of usage */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -3595,22 +4496,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -3620,8 +4545,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -3635,10 +4560,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -3759,22 +4691,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -3784,8 +4740,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -3800,10 +4756,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -3933,6 +4896,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4014,91 +4985,212 @@ constructor(
             class NewFloatingPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_config") private val packageConfig: PackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -4106,12 +5198,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        packageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4121,21 +5237,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageConfig: PackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageConfig: JsonField<PackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -4162,20 +5281,39 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun packageConfig(packageConfig: PackageConfig) =
+                        packageConfig(JsonField.of(packageConfig))
 
-                    fun packageConfig(packageConfig: PackageConfig) = apply {
+                    fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                         this.packageConfig = packageConfig
                     }
 
@@ -4183,9 +5321,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -4194,13 +5331,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -4217,13 +5361,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -4233,12 +5385,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -4253,22 +5412,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -4285,22 +5454,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -4310,12 +5494,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -4324,6 +5516,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -4507,25 +5706,52 @@ constructor(
                 class PackageConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("package_amount") private val packageAmount: String,
-                    @JsonProperty("package_size") private val packageSize: Long,
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    private val packageAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    private val packageSize: JsonField<Long> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** A currency amount to rate usage by */
-                    @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                    fun packageAmount(): String = packageAmount.getRequired("package_amount")
 
                     /**
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                    fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                    /** A currency amount to rate usage by */
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    fun _packageAmount(): JsonField<String> = packageAmount
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    fun _packageSize(): JsonField<Long> = packageSize
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageConfig = apply {
+                        if (!validated) {
+                            packageAmount()
+                            packageSize()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4535,8 +5761,8 @@ constructor(
 
                     class Builder {
 
-                        private var packageAmount: String? = null
-                        private var packageSize: Long? = null
+                        private var packageAmount: JsonField<String>? = null
+                        private var packageSize: JsonField<Long>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4548,7 +5774,11 @@ constructor(
                         }
 
                         /** A currency amount to rate usage by */
-                        fun packageAmount(packageAmount: String) = apply {
+                        fun packageAmount(packageAmount: String) =
+                            packageAmount(JsonField.of(packageAmount))
+
+                        /** A currency amount to rate usage by */
+                        fun packageAmount(packageAmount: JsonField<String>) = apply {
                             this.packageAmount = packageAmount
                         }
 
@@ -4556,7 +5786,13 @@ constructor(
                          * An integer amount to represent package size. For example, 1000 here would
                          * divide usage by 1000 before multiplying by package_amount in rating
                          */
-                        fun packageSize(packageSize: Long) = apply {
+                        fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                        /**
+                         * An integer amount to represent package size. For example, 1000 here would
+                         * divide usage by 1000 before multiplying by package_amount in rating
+                         */
+                        fun packageSize(packageSize: JsonField<Long>) = apply {
                             this.packageSize = packageSize
                         }
 
@@ -4620,22 +5856,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4645,8 +5905,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4660,10 +5920,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -4784,22 +6051,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4809,8 +6100,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4825,10 +6116,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -4958,6 +6256,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5039,91 +6345,212 @@ constructor(
             class NewFloatingMatrixPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -5131,12 +6558,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingMatrixPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        matrixConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5146,21 +6597,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var matrixConfig: MatrixConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5186,30 +6640,48 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixConfig(matrixConfig: MatrixConfig) =
+                        matrixConfig(JsonField.of(matrixConfig))
 
-                    fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                    fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                         this.matrixConfig = matrixConfig
                     }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -5218,13 +6690,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -5237,9 +6716,17 @@ constructor(
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
-                        billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
+                        billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
+
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -5247,7 +6734,7 @@ constructor(
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -5257,12 +6744,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -5277,22 +6771,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -5309,22 +6813,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -5334,12 +6853,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -5348,6 +6875,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -5479,31 +7013,66 @@ constructor(
                 class MatrixConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixConfig = apply {
+                        if (!validated) {
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5513,17 +7082,17 @@ constructor(
 
                     class Builder {
 
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
                             defaultUnitAmount = matrixConfig.defaultUnitAmount
-                            dimensions = matrixConfig.dimensions.toMutableList()
-                            matrixValues = matrixConfig.matrixValues.toMutableList()
+                            dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                            matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -5531,29 +7100,61 @@ constructor(
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -5586,11 +7187,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -5600,28 +7201,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -5631,14 +7259,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -5649,8 +7278,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -5660,13 +7297,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -5697,7 +7344,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -5801,22 +7448,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5826,8 +7497,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5841,10 +7512,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -5965,22 +7643,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5990,8 +7692,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6006,10 +7708,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -6139,6 +7848,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6220,94 +7937,215 @@ constructor(
             class NewFloatingMatrixWithAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("matrix_with_allocation_config")
-                private val matrixWithAllocationConfig: MatrixWithAllocationConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                fun currency(): String = currency.getRequired("currency")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("matrix_with_allocation_config")
                 fun matrixWithAllocationConfig(): MatrixWithAllocationConfig =
+                    matrixWithAllocationConfig.getRequired("matrix_with_allocation_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("matrix_with_allocation_config")
+                @ExcludeMissing
+                fun _matrixWithAllocationConfig(): JsonField<MatrixWithAllocationConfig> =
                     matrixWithAllocationConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -6315,12 +8153,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingMatrixWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        matrixWithAllocationConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6330,21 +8192,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var matrixWithAllocationConfig: MatrixWithAllocationConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>? =
+                        null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6374,30 +8240,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixWithAllocationConfig(
+                        matrixWithAllocationConfig: MatrixWithAllocationConfig
+                    ) = matrixWithAllocationConfig(JsonField.of(matrixWithAllocationConfig))
 
                     fun matrixWithAllocationConfig(
-                        matrixWithAllocationConfig: MatrixWithAllocationConfig
+                        matrixWithAllocationConfig: JsonField<MatrixWithAllocationConfig>
                     ) = apply { this.matrixWithAllocationConfig = matrixWithAllocationConfig }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -6406,13 +8291,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -6429,13 +8321,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -6445,12 +8345,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -6465,22 +8372,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -6497,22 +8414,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -6522,12 +8454,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -6536,6 +8476,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -6667,35 +8614,78 @@ constructor(
                 class MatrixWithAllocationConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("allocation") private val allocation: Double,
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("allocation")
+                    @ExcludeMissing
+                    private val allocation: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Allocation to be used to calculate the price */
-                    @JsonProperty("allocation") fun allocation(): Double = allocation
+                    fun allocation(): Double = allocation.getRequired("allocation")
+
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
+                    /** Allocation to be used to calculate the price */
+                    @JsonProperty("allocation")
+                    @ExcludeMissing
+                    fun _allocation(): JsonField<Double> = allocation
 
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixWithAllocationConfig = apply {
+                        if (!validated) {
+                            allocation()
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6705,10 +8695,10 @@ constructor(
 
                     class Builder {
 
-                        private var allocation: Double? = null
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var allocation: JsonField<Double>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6717,43 +8707,83 @@ constructor(
                             apply {
                                 allocation = matrixWithAllocationConfig.allocation
                                 defaultUnitAmount = matrixWithAllocationConfig.defaultUnitAmount
-                                dimensions = matrixWithAllocationConfig.dimensions.toMutableList()
+                                dimensions =
+                                    matrixWithAllocationConfig.dimensions.map { it.toMutableList() }
                                 matrixValues =
-                                    matrixWithAllocationConfig.matrixValues.toMutableList()
+                                    matrixWithAllocationConfig.matrixValues.map {
+                                        it.toMutableList()
+                                    }
                                 additionalProperties =
                                     matrixWithAllocationConfig.additionalProperties.toMutableMap()
                             }
 
                         /** Allocation to be used to calculate the price */
-                        fun allocation(allocation: Double) = apply { this.allocation = allocation }
+                        fun allocation(allocation: Double) = allocation(JsonField.of(allocation))
+
+                        /** Allocation to be used to calculate the price */
+                        fun allocation(allocation: JsonField<Double>) = apply {
+                            this.allocation = allocation
+                        }
 
                         /**
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -6789,11 +8819,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -6803,28 +8833,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -6834,14 +8891,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -6852,8 +8910,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -6863,13 +8929,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -6900,7 +8976,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -7004,22 +9080,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7029,8 +9129,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7044,10 +9144,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7168,22 +9275,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7193,8 +9324,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7209,10 +9340,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7342,6 +9480,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7423,91 +9569,212 @@ constructor(
             class NewFloatingTieredPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -7515,12 +9782,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7530,21 +9821,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredConfig: TieredConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredConfig: JsonField<TieredConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7570,20 +9864,39 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredConfig(tieredConfig: TieredConfig) =
+                        tieredConfig(JsonField.of(tieredConfig))
 
-                    fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                    fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                         this.tieredConfig = tieredConfig
                     }
 
@@ -7591,9 +9904,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -7602,13 +9914,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -7625,13 +9944,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -7641,12 +9968,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -7661,22 +9995,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -7693,22 +10037,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -7718,12 +10077,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -7732,6 +10099,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -7915,18 +10289,34 @@ constructor(
                 class TieredConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7936,26 +10326,42 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredConfig: TieredConfig) = apply {
-                            tiers = tieredConfig.tiers.toMutableList()
+                            tiers = tieredConfig.tiers.map { it.toMutableList() }
                             additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                         }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for rating based on total usage quantities into the specified tier
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -7983,7 +10389,7 @@ constructor(
                         fun build(): TieredConfig =
                             TieredConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -7992,30 +10398,64 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("first_unit") private val firstUnit: Double,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("last_unit") private val lastUnit: Double?,
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("last_unit")
+                        @ExcludeMissing
+                        private val lastUnit: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                        fun firstUnit(): Double = firstUnit.getRequired("first_unit")
+
+                        /** Amount per unit */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(): Optional<Double> =
+                            Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        fun _firstUnit(): JsonField<Double> = firstUnit
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
                         @JsonProperty("last_unit")
-                        fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                        @ExcludeMissing
+                        fun _lastUnit(): JsonField<Double> = lastUnit
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                firstUnit()
+                                unitAmount()
+                                lastUnit()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -8025,9 +10465,9 @@ constructor(
 
                         class Builder {
 
-                            private var firstUnit: Double? = null
-                            private var unitAmount: String? = null
-                            private var lastUnit: Double? = null
+                            private var firstUnit: JsonField<Double>? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var lastUnit: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -8040,10 +10480,19 @@ constructor(
                             }
 
                             /** Inclusive tier starting value */
-                            fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                            fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                            /** Inclusive tier starting value */
+                            fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                                this.firstUnit = firstUnit
+                            }
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -8051,7 +10500,8 @@ constructor(
                              * Exclusive tier ending value. If null, this is treated as the last
                              * tier
                              */
-                            fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                            fun lastUnit(lastUnit: Double?) =
+                                lastUnit(JsonField.ofNullable(lastUnit))
 
                             /**
                              * Exclusive tier ending value. If null, this is treated as the last
@@ -8069,6 +10519,14 @@ constructor(
                             fun lastUnit(lastUnit: Optional<Double>) =
                                 lastUnit(lastUnit.orElse(null) as Double?)
 
+                            /**
+                             * Exclusive tier ending value. If null, this is treated as the last
+                             * tier
+                             */
+                            fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                                this.lastUnit = lastUnit
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -8148,22 +10606,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8173,8 +10655,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8188,10 +10670,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8312,22 +10801,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8337,8 +10850,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8353,10 +10866,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8486,6 +11006,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8567,92 +11095,213 @@ constructor(
             class NewFloatingTieredBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_bps_config")
+                @ExcludeMissing
+                private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredBpsConfig(): TieredBpsConfig =
+                    tieredBpsConfig.getRequired("tiered_bps_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_bps_config")
-                fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+                @ExcludeMissing
+                fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -8660,12 +11309,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredBpsPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredBpsConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -8675,21 +11348,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredBpsConfig: TieredBpsConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -8717,20 +11393,39 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                        tieredBpsConfig(JsonField.of(tieredBpsConfig))
 
-                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                    fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                         this.tieredBpsConfig = tieredBpsConfig
                     }
 
@@ -8738,9 +11433,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -8749,13 +11443,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -8772,13 +11473,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -8788,12 +11497,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -8808,22 +11524,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -8840,22 +11566,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -8865,12 +11606,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -8879,6 +11628,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -9062,7 +11818,9 @@ constructor(
                 class TieredBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -9071,12 +11829,29 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9086,13 +11861,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                            tiers = tieredBpsConfig.tiers.toMutableList()
+                            tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties =
                                 tieredBpsConfig.additionalProperties.toMutableMap()
                         }
@@ -9101,14 +11876,31 @@ constructor(
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                         * specified tiers
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -9136,7 +11928,7 @@ constructor(
                         fun build(): TieredBpsConfig =
                             TieredBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -9145,33 +11937,71 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("minimum_amount") private val minimumAmount: String,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Per-event basis point rate */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Inclusive tier starting value */
+                        fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Per-event basis point rate */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        fun _minimumAmount(): JsonField<String> = minimumAmount
 
                         /** Exclusive tier ending value */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** Per unit maximum to charge */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                minimumAmount()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -9181,10 +12011,10 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var minimumAmount: String? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var minimumAmount: JsonField<String>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -9198,31 +12028,46 @@ constructor(
                             }
 
                             /** Per-event basis point rate */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Per-event basis point rate */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
+
+                            /** Inclusive tier starting value */
+                            fun minimumAmount(minimumAmount: String) =
+                                minimumAmount(JsonField.of(minimumAmount))
 
                             /** Inclusive tier starting value */
-                            fun minimumAmount(minimumAmount: String) = apply {
+                            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                                 this.minimumAmount = minimumAmount
                             }
 
                             /** Exclusive tier ending value */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Exclusive tier ending value */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** Per unit maximum to charge */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Exclusive tier ending value */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** Per unit maximum to charge */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -9301,22 +12146,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9326,8 +12195,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9341,10 +12210,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -9465,22 +12341,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9490,8 +12390,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9506,10 +12406,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -9639,6 +12546,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9703,108 +12618,229 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingTieredBpsPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredBpsConfig == other.tieredBpsConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingTieredBpsPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredBpsConfig == other.tieredBpsConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredBpsConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingTieredBpsPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredBpsConfig=$tieredBpsConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingBpsPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredBpsConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingTieredBpsPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredBpsConfig=$tieredBpsConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingBpsPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
-                @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -9812,12 +12848,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingBpsPrice = apply {
+                    if (!validated) {
+                        bpsConfig().validate()
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9827,21 +12887,24 @@ constructor(
 
                 class Builder {
 
-                    private var bpsConfig: BpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var bpsConfig: JsonField<BpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9866,29 +12929,48 @@ constructor(
                             newFloatingBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                    fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                    fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                        this.bpsConfig = bpsConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -9897,13 +12979,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -9920,13 +13009,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -9936,12 +13033,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -9956,22 +13060,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -9988,22 +13102,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -10013,12 +13142,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -10027,6 +13164,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -10074,23 +13218,45 @@ constructor(
                 class BpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis point take rate per event */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis point take rate per event */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Optional currency amount maximum to cap spend per event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BpsConfig = apply {
+                        if (!validated) {
+                            bps()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10100,8 +13266,8 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10113,17 +13279,24 @@ constructor(
                         }
 
                         /** Basis point take rate per event */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis point take rate per event */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Optional currency amount maximum to cap spend per event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
-                        }
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                         /** Optional currency amount maximum to cap spend per event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Optional currency amount maximum to cap spend per event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -10314,22 +13487,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10339,8 +13536,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10354,10 +13551,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -10478,22 +13682,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10503,8 +13731,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10519,10 +13747,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -10652,6 +13887,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10733,91 +13976,212 @@ constructor(
             class NewFloatingBulkBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+                fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -10825,12 +14189,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingBulkBpsPrice = apply {
+                    if (!validated) {
+                        bulkBpsConfig().validate()
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10840,21 +14228,24 @@ constructor(
 
                 class Builder {
 
-                    private var bulkBpsConfig: BulkBpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10880,31 +14271,49 @@ constructor(
                             newFloatingBulkBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                        bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                    fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                         this.bulkBpsConfig = bulkBpsConfig
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -10913,13 +14322,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -10936,13 +14352,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -10952,12 +14376,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -10972,22 +14403,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -11004,22 +14445,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -11029,12 +14485,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -11043,6 +14507,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -11092,7 +14563,9 @@ constructor(
                 class BulkBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -11101,12 +14574,29 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11116,13 +14606,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                            tiers = bulkBpsConfig.tiers.toMutableList()
+                            tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                         }
 
@@ -11130,14 +14620,31 @@ constructor(
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a bulk BPS pricing model where all usage is aggregated to a
+                         * single tier based on total volume
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -11165,7 +14672,7 @@ constructor(
                         fun build(): BulkBpsConfig =
                             BulkBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -11174,29 +14681,59 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Basis points to rate on */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Upper bound for tier */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Basis points to rate on */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Upper bound for tier */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** The maximum amount to charge for any one event */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -11206,9 +14743,9 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -11221,26 +14758,37 @@ constructor(
                             }
 
                             /** Basis points to rate on */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Basis points to rate on */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Upper bound for tier */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Upper bound for tier */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** The maximum amount to charge for any one event */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Upper bound for tier */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** The maximum amount to charge for any one event */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -11450,22 +14998,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11475,8 +15047,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -11490,10 +15062,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -11614,22 +15193,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11639,8 +15242,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -11655,10 +15258,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -11788,6 +15398,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11869,91 +15487,212 @@ constructor(
             class NewFloatingBulkPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+                fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -11961,12 +15700,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingBulkPrice = apply {
+                    if (!validated) {
+                        bulkConfig().validate()
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11976,21 +15739,24 @@ constructor(
 
                 class Builder {
 
-                    private var bulkConfig: BulkConfig? = null
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var bulkConfig: JsonField<BulkConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -12015,29 +15781,48 @@ constructor(
                             newFloatingBulkPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                    fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                    fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                        this.bulkConfig = bulkConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -12046,13 +15831,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -12069,13 +15861,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -12085,12 +15885,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -12105,22 +15912,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -12137,22 +15954,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -12162,12 +15994,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -12176,6 +16016,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -12223,18 +16070,34 @@ constructor(
                 class BulkConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Bulk tiers for rating based on total usage volume */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12244,22 +16107,36 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkConfig: BulkConfig) = apply {
-                            tiers = bulkConfig.tiers.toMutableList()
+                            tiers = bulkConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                         }
 
                         /** Bulk tiers for rating based on total usage volume */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /** Bulk tiers for rating based on total usage volume */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /** Bulk tiers for rating based on total usage volume */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -12287,7 +16164,7 @@ constructor(
                         fun build(): BulkConfig =
                             BulkConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -12296,24 +16173,48 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_units")
+                        @ExcludeMissing
+                        private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /** Upper bound for this tier */
+                        fun maximumUnits(): Optional<Double> =
+                            Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /** Upper bound for this tier */
                         @JsonProperty("maximum_units")
-                        fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                        @ExcludeMissing
+                        fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                unitAmount()
+                                maximumUnits()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -12323,8 +16224,8 @@ constructor(
 
                         class Builder {
 
-                            private var unitAmount: String? = null
-                            private var maximumUnits: Double? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var maximumUnits: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -12336,14 +16237,17 @@ constructor(
                             }
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
                             /** Upper bound for this tier */
-                            fun maximumUnits(maximumUnits: Double?) = apply {
-                                this.maximumUnits = maximumUnits
-                            }
+                            fun maximumUnits(maximumUnits: Double?) =
+                                maximumUnits(JsonField.ofNullable(maximumUnits))
 
                             /** Upper bound for this tier */
                             fun maximumUnits(maximumUnits: Double) =
@@ -12356,6 +16260,11 @@ constructor(
                             fun maximumUnits(maximumUnits: Optional<Double>) =
                                 maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                            /** Upper bound for this tier */
+                            fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                                this.maximumUnits = maximumUnits
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -12566,22 +16475,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12591,8 +16524,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -12606,10 +16539,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12730,22 +16670,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12755,8 +16719,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -12771,10 +16735,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12904,6 +16875,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12968,61 +16947,174 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingBulkPrice && bulkConfig == other.bulkConfig && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingBulkPrice && bulkConfig == other.bulkConfig && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(bulkConfig, cadence, currency, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingBulkPrice{bulkConfig=$bulkConfig, cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingThresholdTotalAmountPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("threshold_total_amount_config")
+                @ExcludeMissing
+                private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                    thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(bulkConfig, cadence, currency, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingBulkPrice{bulkConfig=$bulkConfig, cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingThresholdTotalAmountPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("threshold_total_amount_config")
-                private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("threshold_total_amount_config")
-                fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                @ExcludeMissing
+                fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                     thresholdTotalAmountConfig
 
                 /**
@@ -13030,49 +17122,57 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -13080,12 +17180,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingThresholdTotalAmountPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        thresholdTotalAmountConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13095,21 +17219,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -13139,30 +17267,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: String) = currency(JsonField.of(currency))
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun thresholdTotalAmountConfig(
                         thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                    ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                    fun thresholdTotalAmountConfig(
+                        thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                     ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -13171,13 +17318,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -13194,13 +17348,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -13210,12 +17372,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -13230,22 +17399,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -13262,22 +17441,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -13287,12 +17481,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -13301,6 +17503,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -13492,6 +17701,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): ThresholdTotalAmountConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13563,22 +17780,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13588,8 +17829,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13603,10 +17844,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13727,22 +17975,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13752,8 +18024,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13768,10 +18040,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13901,6 +18180,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13960,115 +18247,235 @@ constructor(
                     override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
                 }
 
-                override fun equals(other: Any?): Boolean {
-                    if (this === other) {
-                        return true
-                    }
+                override fun equals(other: Any?): Boolean {
+                    if (this === other) {
+                        return true
+                    }
+
+                    return /* spotless:off */ other is NewFloatingThresholdTotalAmountPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && thresholdTotalAmountConfig == other.thresholdTotalAmountConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, thresholdTotalAmountConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingThresholdTotalAmountPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, thresholdTotalAmountConfig=$thresholdTotalAmountConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingTieredPackagePrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_package_config")
+                @ExcludeMissing
+                private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageConfig(): TieredPackageConfig =
+                    tieredPackageConfig.getRequired("tiered_package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                    return /* spotless:off */ other is NewFloatingThresholdTotalAmountPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && thresholdTotalAmountConfig == other.thresholdTotalAmountConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, thresholdTotalAmountConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingThresholdTotalAmountPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, thresholdTotalAmountConfig=$thresholdTotalAmountConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingTieredPackagePrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_package_config")
-                private val tieredPackageConfig: TieredPackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_config")
-                fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+                @ExcludeMissing
+                fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -14076,12 +18483,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14091,21 +18522,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageConfig: TieredPackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -14134,30 +18568,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                        this.tieredPackageConfig = tieredPackageConfig
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
                     }
 
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                        tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                    fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                        apply {
+                            this.tieredPackageConfig = tieredPackageConfig
+                        }
+
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -14166,13 +18619,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -14189,13 +18649,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -14205,12 +18673,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -14225,22 +18700,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -14257,22 +18742,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -14282,12 +18782,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -14296,6 +18804,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -14487,6 +19002,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14557,22 +19080,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14582,8 +19129,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14597,10 +19144,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14721,22 +19275,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14746,8 +19324,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14762,10 +19340,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14895,6 +19480,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14959,110 +19552,230 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingTieredPackagePrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredPackageConfig == other.tieredPackageConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingTieredPackagePrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredPackageConfig == other.tieredPackageConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredPackageConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingTieredPackagePrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredPackageConfig=$tieredPackageConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingGroupedTieredPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("grouped_tiered_config")
+                @ExcludeMissing
+                private val groupedTieredConfig: JsonField<GroupedTieredConfig> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                fun groupedTieredConfig(): GroupedTieredConfig =
+                    groupedTieredConfig.getRequired("grouped_tiered_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredPackageConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingTieredPackagePrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredPackageConfig=$tieredPackageConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingGroupedTieredPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("grouped_tiered_config")
-                private val groupedTieredConfig: GroupedTieredConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 @JsonProperty("grouped_tiered_config")
-                fun groupedTieredConfig(): GroupedTieredConfig = groupedTieredConfig
+                @ExcludeMissing
+                fun _groupedTieredConfig(): JsonField<GroupedTieredConfig> = groupedTieredConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -15070,12 +19783,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingGroupedTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        groupedTieredConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15085,21 +19822,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var groupedTieredConfig: GroupedTieredConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var groupedTieredConfig: JsonField<GroupedTieredConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -15128,30 +19868,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
-                    fun groupedTieredConfig(groupedTieredConfig: GroupedTieredConfig) = apply {
-                        this.groupedTieredConfig = groupedTieredConfig
-                    }
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    fun groupedTieredConfig(groupedTieredConfig: GroupedTieredConfig) =
+                        groupedTieredConfig(JsonField.of(groupedTieredConfig))
+
+                    fun groupedTieredConfig(groupedTieredConfig: JsonField<GroupedTieredConfig>) =
+                        apply {
+                            this.groupedTieredConfig = groupedTieredConfig
+                        }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -15160,13 +19919,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -15183,13 +19949,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -15199,12 +19973,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -15219,22 +20000,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -15251,22 +20042,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -15276,12 +20082,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -15290,6 +20104,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -15429,6 +20250,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedTieredConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15551,22 +20380,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15576,8 +20429,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15591,10 +20444,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15715,22 +20575,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15740,8 +20624,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15756,10 +20640,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15889,6 +20780,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15953,110 +20852,232 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingGroupedTieredPrice && cadence == other.cadence && currency == other.currency && groupedTieredConfig == other.groupedTieredConfig && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingGroupedTieredPrice && cadence == other.cadence && currency == other.currency && groupedTieredConfig == other.groupedTieredConfig && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedTieredConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingGroupedTieredPrice{cadence=$cadence, currency=$currency, groupedTieredConfig=$groupedTieredConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingTieredWithMinimumPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_with_minimum_config")
+                @ExcludeMissing
+                private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                    tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedTieredConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingGroupedTieredPrice{cadence=$cadence, currency=$currency, groupedTieredConfig=$groupedTieredConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingTieredWithMinimumPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_with_minimum_config")
-                private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_minimum_config")
-                fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+                @ExcludeMissing
+                fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                    tieredWithMinimumConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -16064,12 +21085,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16079,21 +21124,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -16123,31 +21171,48 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                        apply {
-                            this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                        }
+                        tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                    fun tieredWithMinimumConfig(
+                        tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                    ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -16156,13 +21221,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -16179,13 +21251,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -16195,12 +21275,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -16215,22 +21302,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -16247,22 +21344,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -16272,12 +21384,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -16286,6 +21406,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -16477,6 +21604,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16548,22 +21683,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16573,8 +21732,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16588,10 +21747,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16712,22 +21878,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16737,8 +21927,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16753,10 +21943,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16886,6 +22083,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16945,66 +22150,179 @@ constructor(
                     override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
                 }
 
-                override fun equals(other: Any?): Boolean {
-                    if (this === other) {
-                        return true
-                    }
+                override fun equals(other: Any?): Boolean {
+                    if (this === other) {
+                        return true
+                    }
+
+                    return /* spotless:off */ other is NewFloatingTieredWithMinimumPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithMinimumConfig == other.tieredWithMinimumConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredWithMinimumConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingTieredWithMinimumPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredWithMinimumConfig=$tieredWithMinimumConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingPackageWithAllocationPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_with_allocation_config")
+                @ExcludeMissing
+                private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                    packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                    return /* spotless:off */ other is NewFloatingTieredWithMinimumPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithMinimumConfig == other.tieredWithMinimumConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredWithMinimumConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingTieredWithMinimumPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredWithMinimumConfig=$tieredWithMinimumConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingPackageWithAllocationPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_with_allocation_config")
-                private val packageWithAllocationConfig: PackageWithAllocationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("package_with_allocation_config")
-                fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                @ExcludeMissing
+                fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                     packageWithAllocationConfig
 
                 /**
@@ -17012,49 +22330,57 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -17062,12 +22388,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingPackageWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        packageWithAllocationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17077,21 +22427,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageWithAllocationConfig:
+                        JsonField<PackageWithAllocationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -17124,30 +22479,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: String) = currency(JsonField.of(currency))
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun packageWithAllocationConfig(
                         packageWithAllocationConfig: PackageWithAllocationConfig
+                    ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                    fun packageWithAllocationConfig(
+                        packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                     ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -17156,13 +22530,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -17179,13 +22560,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -17195,12 +22584,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -17215,22 +22611,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -17247,22 +22653,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -17272,12 +22693,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -17286,6 +22715,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -17477,6 +22913,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageWithAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17549,22 +22993,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17574,8 +23042,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17589,10 +23057,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17713,22 +23188,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17738,8 +23237,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17754,10 +23253,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17887,6 +23393,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17951,61 +23465,175 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingPackageWithAllocationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && packageWithAllocationConfig == other.packageWithAllocationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingPackageWithAllocationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && packageWithAllocationConfig == other.packageWithAllocationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, packageWithAllocationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingPackageWithAllocationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, packageWithAllocationConfig=$packageWithAllocationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingTieredPackageWithMinimumPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_package_with_minimum_config")
+                @ExcludeMissing
+                private val tieredPackageWithMinimumConfig:
+                    JsonField<TieredPackageWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageWithMinimumConfig(): TieredPackageWithMinimumConfig =
+                    tieredPackageWithMinimumConfig.getRequired("tiered_package_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, packageWithAllocationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingPackageWithAllocationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, packageWithAllocationConfig=$packageWithAllocationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingTieredPackageWithMinimumPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_package_with_minimum_config")
-                private val tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_with_minimum_config")
-                fun tieredPackageWithMinimumConfig(): TieredPackageWithMinimumConfig =
+                @ExcludeMissing
+                fun _tieredPackageWithMinimumConfig(): JsonField<TieredPackageWithMinimumConfig> =
                     tieredPackageWithMinimumConfig
 
                 /**
@@ -18013,49 +23641,57 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -18063,12 +23699,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredPackageWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18078,22 +23738,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig? =
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageWithMinimumConfig:
+                        JsonField<TieredPackageWithMinimumConfig>? =
                         null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -18127,21 +23791,41 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredPackageWithMinimumConfig(
                         tieredPackageWithMinimumConfig: TieredPackageWithMinimumConfig
+                    ) = tieredPackageWithMinimumConfig(JsonField.of(tieredPackageWithMinimumConfig))
+
+                    fun tieredPackageWithMinimumConfig(
+                        tieredPackageWithMinimumConfig: JsonField<TieredPackageWithMinimumConfig>
                     ) = apply {
                         this.tieredPackageWithMinimumConfig = tieredPackageWithMinimumConfig
                     }
@@ -18150,9 +23834,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -18161,13 +23844,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -18184,13 +23874,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -18200,12 +23898,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -18220,22 +23925,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -18252,22 +23967,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -18277,12 +24007,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -18291,6 +24029,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -18483,6 +24228,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18555,22 +24308,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18580,8 +24357,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18595,10 +24372,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18719,22 +24503,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18744,8 +24552,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18760,10 +24568,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18893,6 +24708,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18957,110 +24780,232 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingTieredPackageWithMinimumPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredPackageWithMinimumConfig == other.tieredPackageWithMinimumConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingTieredPackageWithMinimumPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredPackageWithMinimumConfig == other.tieredPackageWithMinimumConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredPackageWithMinimumConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingTieredPackageWithMinimumPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredPackageWithMinimumConfig=$tieredPackageWithMinimumConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingUnitWithPercentPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_with_percent_config")
+                @ExcludeMissing
+                private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithPercentConfig(): UnitWithPercentConfig =
+                    unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredPackageWithMinimumConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingTieredPackageWithMinimumPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredPackageWithMinimumConfig=$tieredPackageWithMinimumConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingUnitWithPercentPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_with_percent_config")
-                private val unitWithPercentConfig: UnitWithPercentConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_percent_config")
-                fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+                @ExcludeMissing
+                fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> =
+                    unitWithPercentConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -19068,12 +25013,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingUnitWithPercentPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithPercentConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19083,21 +25052,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -19127,31 +25099,48 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: String) = currency(JsonField.of(currency))
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
-                        apply {
-                            this.unitWithPercentConfig = unitWithPercentConfig
-                        }
+                        unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                    fun unitWithPercentConfig(
+                        unitWithPercentConfig: JsonField<UnitWithPercentConfig>
+                    ) = apply { this.unitWithPercentConfig = unitWithPercentConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -19160,13 +25149,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -19183,13 +25179,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -19199,12 +25203,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -19219,22 +25230,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -19251,22 +25272,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -19276,12 +25312,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -19290,6 +25334,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -19481,6 +25532,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithPercentConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19551,22 +25610,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19576,8 +25659,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19591,10 +25674,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19715,22 +25805,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19740,8 +25854,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19756,10 +25870,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19889,6 +26010,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19948,66 +26077,179 @@ constructor(
                     override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
                 }
 
-                override fun equals(other: Any?): Boolean {
-                    if (this === other) {
-                        return true
-                    }
+                override fun equals(other: Any?): Boolean {
+                    if (this === other) {
+                        return true
+                    }
+
+                    return /* spotless:off */ other is NewFloatingUnitWithPercentPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithPercentConfig == other.unitWithPercentConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, unitWithPercentConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingUnitWithPercentPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, unitWithPercentConfig=$unitWithPercentConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingTieredWithProrationPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_with_proration_config")
+                @ExcludeMissing
+                private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                    tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                    return /* spotless:off */ other is NewFloatingUnitWithPercentPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithPercentConfig == other.unitWithPercentConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, unitWithPercentConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingUnitWithPercentPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, unitWithPercentConfig=$unitWithPercentConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingTieredWithProrationPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_with_proration_config")
-                private val tieredWithProrationConfig: TieredWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_proration_config")
-                fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                @ExcludeMissing
+                fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
                     tieredWithProrationConfig
 
                 /**
@@ -20015,49 +26257,57 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -20065,12 +26315,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingTieredWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20080,21 +26354,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -20124,30 +26402,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithProrationConfig(
                         tieredWithProrationConfig: TieredWithProrationConfig
+                    ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                    fun tieredWithProrationConfig(
+                        tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                     ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -20156,13 +26453,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -20179,13 +26483,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -20195,12 +26507,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -20215,22 +26534,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -20247,22 +26576,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -20272,12 +26616,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -20286,6 +26638,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -20477,6 +26836,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20548,22 +26915,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20573,8 +26964,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20588,10 +26979,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20712,22 +27110,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20737,8 +27159,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20753,10 +27175,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20886,6 +27315,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20950,110 +27387,232 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingTieredWithProrationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithProrationConfig == other.tieredWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingTieredWithProrationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && tieredWithProrationConfig == other.tieredWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingTieredWithProrationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredWithProrationConfig=$tieredWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingUnitWithProrationPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_with_proration_config")
+                @ExcludeMissing
+                private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithProrationConfig(): UnitWithProrationConfig =
+                    unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, tieredWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingTieredWithProrationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, tieredWithProrationConfig=$tieredWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingUnitWithProrationPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_with_proration_config")
-                private val unitWithProrationConfig: UnitWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_proration_config")
-                fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+                @ExcludeMissing
+                fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                    unitWithProrationConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -21061,12 +27620,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingUnitWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21076,21 +27659,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -21120,31 +27706,48 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                        apply {
-                            this.unitWithProrationConfig = unitWithProrationConfig
-                        }
+                        unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                    fun unitWithProrationConfig(
+                        unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                    ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -21153,13 +27756,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -21176,13 +27786,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -21192,12 +27810,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -21212,22 +27837,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -21244,22 +27879,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -21269,12 +27919,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -21283,6 +27941,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -21474,6 +28139,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21545,22 +28218,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21570,8 +28267,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21585,10 +28282,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21709,22 +28413,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21734,8 +28462,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21750,10 +28478,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21883,6 +28618,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21942,115 +28685,237 @@ constructor(
                     override fun toString() = "Metadata{additionalProperties=$additionalProperties}"
                 }
 
-                override fun equals(other: Any?): Boolean {
-                    if (this === other) {
-                        return true
-                    }
+                override fun equals(other: Any?): Boolean {
+                    if (this === other) {
+                        return true
+                    }
+
+                    return /* spotless:off */ other is NewFloatingUnitWithProrationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithProrationConfig == other.unitWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, unitWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingUnitWithProrationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, unitWithProrationConfig=$unitWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingGroupedAllocationPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("grouped_allocation_config")
+                @ExcludeMissing
+                private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                fun groupedAllocationConfig(): GroupedAllocationConfig =
+                    groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                    return /* spotless:off */ other is NewFloatingUnitWithProrationPrice && cadence == other.cadence && currency == other.currency && itemId == other.itemId && modelType == other.modelType && name == other.name && unitWithProrationConfig == other.unitWithProrationConfig && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, itemId, modelType, name, unitWithProrationConfig, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun hashCode(): Int = hashCode
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-                override fun toString() =
-                    "NewFloatingUnitWithProrationPrice{cadence=$cadence, currency=$currency, itemId=$itemId, modelType=$modelType, name=$name, unitWithProrationConfig=$unitWithProrationConfig, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
 
-            @NoAutoDetect
-            class NewFloatingGroupedAllocationPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("grouped_allocation_config")
-                private val groupedAllocationConfig: GroupedAllocationConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 @JsonProperty("grouped_allocation_config")
-                fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+                @ExcludeMissing
+                fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                    groupedAllocationConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -22058,12 +28923,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingGroupedAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        groupedAllocationConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22073,21 +28962,24 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -22117,31 +29009,48 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                        apply {
-                            this.groupedAllocationConfig = groupedAllocationConfig
-                        }
+                        groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                    fun groupedAllocationConfig(
+                        groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                    ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -22150,13 +29059,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -22173,13 +29089,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -22189,12 +29113,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -22209,22 +29140,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -22241,22 +29182,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -22266,12 +29222,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -22280,6 +29244,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -22419,6 +29390,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22542,22 +29521,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22567,8 +29570,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22582,10 +29585,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22706,22 +29716,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22731,8 +29765,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22747,10 +29781,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22880,6 +29921,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22944,111 +29993,235 @@ constructor(
                         return true
                     }
 
-                    return /* spotless:off */ other is NewFloatingGroupedAllocationPrice && cadence == other.cadence && currency == other.currency && groupedAllocationConfig == other.groupedAllocationConfig && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
-                }
+                    return /* spotless:off */ other is NewFloatingGroupedAllocationPrice && cadence == other.cadence && currency == other.currency && groupedAllocationConfig == other.groupedAllocationConfig && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
+                }
+
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedAllocationConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingGroupedAllocationPrice{cadence=$cadence, currency=$currency, groupedAllocationConfig=$groupedAllocationConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingGroupedWithProratedMinimumPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("grouped_with_prorated_minimum_config")
+                @ExcludeMissing
+                private val groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
+                    groupedWithProratedMinimumConfig.getRequired(
+                        "grouped_with_prorated_minimum_config"
+                    )
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedAllocationConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingGroupedAllocationPrice{cadence=$cadence, currency=$currency, groupedAllocationConfig=$groupedAllocationConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingGroupedWithProratedMinimumPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("grouped_with_prorated_minimum_config")
-                private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 @JsonProperty("grouped_with_prorated_minimum_config")
-                fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
-                    groupedWithProratedMinimumConfig
+                @ExcludeMissing
+                fun _groupedWithProratedMinimumConfig():
+                    JsonField<GroupedWithProratedMinimumConfig> = groupedWithProratedMinimumConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -23056,12 +30229,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingGroupedWithProratedMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        groupedWithProratedMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -23071,23 +30268,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
                     private var groupedWithProratedMinimumConfig:
-                        GroupedWithProratedMinimumConfig? =
+                        JsonField<GroupedWithProratedMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -23123,32 +30323,55 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     fun groupedWithProratedMinimumConfig(
                         groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                    ) =
+                        groupedWithProratedMinimumConfig(
+                            JsonField.of(groupedWithProratedMinimumConfig)
+                        )
+
+                    fun groupedWithProratedMinimumConfig(
+                        groupedWithProratedMinimumConfig:
+                            JsonField<GroupedWithProratedMinimumConfig>
                     ) = apply {
                         this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -23157,13 +30380,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -23180,13 +30410,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -23196,12 +30434,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -23216,22 +30461,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -23248,22 +30503,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -23273,12 +30543,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -23287,6 +30565,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -23426,6 +30711,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithProratedMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23551,22 +30844,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23576,8 +30893,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23591,10 +30908,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23715,22 +31039,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23740,8 +31088,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23756,10 +31104,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23889,6 +31244,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23956,108 +31319,232 @@ constructor(
                     return /* spotless:off */ other is NewFloatingGroupedWithProratedMinimumPrice && cadence == other.cadence && currency == other.currency && groupedWithProratedMinimumConfig == other.groupedWithProratedMinimumConfig && itemId == other.itemId && modelType == other.modelType && name == other.name && billableMetricId == other.billableMetricId && billedInAdvance == other.billedInAdvance && billingCycleConfiguration == other.billingCycleConfiguration && conversionRate == other.conversionRate && externalPriceId == other.externalPriceId && fixedPriceQuantity == other.fixedPriceQuantity && invoiceGroupingKey == other.invoiceGroupingKey && invoicingCycleConfiguration == other.invoicingCycleConfiguration && metadata == other.metadata && additionalProperties == other.additionalProperties /* spotless:on */
                 }
 
-                /* spotless:off */
-                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedWithProratedMinimumConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
-                /* spotless:on */
+                /* spotless:off */
+                private val hashCode: Int by lazy { Objects.hash(cadence, currency, groupedWithProratedMinimumConfig, itemId, modelType, name, billableMetricId, billedInAdvance, billingCycleConfiguration, conversionRate, externalPriceId, fixedPriceQuantity, invoiceGroupingKey, invoicingCycleConfiguration, metadata, additionalProperties) }
+                /* spotless:on */
+
+                override fun hashCode(): Int = hashCode
+
+                override fun toString() =
+                    "NewFloatingGroupedWithProratedMinimumPrice{cadence=$cadence, currency=$currency, groupedWithProratedMinimumConfig=$groupedWithProratedMinimumConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
+            }
+
+            @NoAutoDetect
+            class NewFloatingGroupedWithMeteredMinimumPrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("grouped_with_metered_minimum_config")
+                @ExcludeMissing
+                private val groupedWithMeteredMinimumConfig:
+                    JsonField<GroupedWithMeteredMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                fun groupedWithMeteredMinimumConfig(): GroupedWithMeteredMinimumConfig =
+                    groupedWithMeteredMinimumConfig.getRequired(
+                        "grouped_with_metered_minimum_config"
+                    )
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
 
-                override fun hashCode(): Int = hashCode
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
 
-                override fun toString() =
-                    "NewFloatingGroupedWithProratedMinimumPrice{cadence=$cadence, currency=$currency, groupedWithProratedMinimumConfig=$groupedWithProratedMinimumConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
-            }
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
 
-            @NoAutoDetect
-            class NewFloatingGroupedWithMeteredMinimumPrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("grouped_with_metered_minimum_config")
-                private val groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 @JsonProperty("grouped_with_metered_minimum_config")
-                fun groupedWithMeteredMinimumConfig(): GroupedWithMeteredMinimumConfig =
+                @ExcludeMissing
+                fun _groupedWithMeteredMinimumConfig(): JsonField<GroupedWithMeteredMinimumConfig> =
                     groupedWithMeteredMinimumConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -24065,12 +31552,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingGroupedWithMeteredMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        groupedWithMeteredMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -24080,22 +31591,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig? =
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var groupedWithMeteredMinimumConfig:
+                        JsonField<GroupedWithMeteredMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -24131,32 +31646,54 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: String) = currency(JsonField.of(currency))
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     fun groupedWithMeteredMinimumConfig(
                         groupedWithMeteredMinimumConfig: GroupedWithMeteredMinimumConfig
+                    ) =
+                        groupedWithMeteredMinimumConfig(
+                            JsonField.of(groupedWithMeteredMinimumConfig)
+                        )
+
+                    fun groupedWithMeteredMinimumConfig(
+                        groupedWithMeteredMinimumConfig: JsonField<GroupedWithMeteredMinimumConfig>
                     ) = apply {
                         this.groupedWithMeteredMinimumConfig = groupedWithMeteredMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -24165,13 +31702,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -24188,13 +31732,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -24204,12 +31756,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -24224,22 +31783,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -24256,22 +31825,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -24281,12 +31865,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -24295,6 +31887,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -24434,6 +32033,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithMeteredMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -24559,22 +32166,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -24584,8 +32215,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -24599,10 +32230,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -24723,22 +32361,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -24748,8 +32410,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -24764,10 +32426,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -24897,6 +32566,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -24974,98 +32651,219 @@ constructor(
                     "NewFloatingGroupedWithMeteredMinimumPrice{cadence=$cadence, currency=$currency, groupedWithMeteredMinimumConfig=$groupedWithMeteredMinimumConfig, itemId=$itemId, modelType=$modelType, name=$name, billableMetricId=$billableMetricId, billedInAdvance=$billedInAdvance, billingCycleConfiguration=$billingCycleConfiguration, conversionRate=$conversionRate, externalPriceId=$externalPriceId, fixedPriceQuantity=$fixedPriceQuantity, invoiceGroupingKey=$invoiceGroupingKey, invoicingCycleConfiguration=$invoicingCycleConfiguration, metadata=$metadata, additionalProperties=$additionalProperties}"
             }
 
-            @NoAutoDetect
-            class NewFloatingMatrixWithDisplayNamePrice
-            @JsonCreator
-            private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_with_display_name_config")
-                private val matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
-                @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
-                @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonAnySetter
-                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
-            ) {
+            @NoAutoDetect
+            class NewFloatingMatrixWithDisplayNamePrice
+            @JsonCreator
+            private constructor(
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_with_display_name_config")
+                @ExcludeMissing
+                private val matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
+                @JsonProperty("billing_cycle_configuration")
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("invoicing_cycle_configuration")
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonAnySetter
+                private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
+            ) {
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixWithDisplayNameConfig(): MatrixWithDisplayNameConfig =
+                    matrixWithDisplayNameConfig.getRequired("matrix_with_display_name_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 @JsonProperty("matrix_with_display_name_config")
-                fun matrixWithDisplayNameConfig(): MatrixWithDisplayNameConfig =
+                @ExcludeMissing
+                fun _matrixWithDisplayNameConfig(): JsonField<MatrixWithDisplayNameConfig> =
                     matrixWithDisplayNameConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -25073,12 +32871,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingMatrixWithDisplayNamePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        itemId()
+                        matrixWithDisplayNameConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25088,21 +32910,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixWithDisplayNameConfig:
+                        JsonField<MatrixWithDisplayNameConfig>? =
+                        null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -25135,30 +32962,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
                     fun matrixWithDisplayNameConfig(
                         matrixWithDisplayNameConfig: MatrixWithDisplayNameConfig
+                    ) = matrixWithDisplayNameConfig(JsonField.of(matrixWithDisplayNameConfig))
+
+                    fun matrixWithDisplayNameConfig(
+                        matrixWithDisplayNameConfig: JsonField<MatrixWithDisplayNameConfig>
                     ) = apply { this.matrixWithDisplayNameConfig = matrixWithDisplayNameConfig }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -25167,13 +33013,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -25190,13 +33043,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -25206,12 +33067,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -25226,22 +33094,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -25258,22 +33136,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -25283,12 +33176,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -25297,6 +33198,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -25436,6 +33344,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixWithDisplayNameConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -25560,22 +33476,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -25585,8 +33525,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -25600,10 +33540,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -25724,22 +33671,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -25749,8 +33720,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -25765,10 +33736,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -25898,6 +33876,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -25980,92 +33966,214 @@ constructor(
             @JsonCreator
             private constructor(
                 @JsonProperty("bulk_with_proration_config")
-                private val bulkWithProrationConfig: BulkWithProrationConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                    bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                fun currency(): String = currency.getRequired("currency")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
                 @JsonProperty("bulk_with_proration_config")
-                fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+                @ExcludeMissing
+                fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                    bulkWithProrationConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -26073,12 +34181,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingBulkWithProrationPrice = apply {
+                    if (!validated) {
+                        bulkWithProrationConfig().validate()
+                        cadence()
+                        currency()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -26088,21 +34220,24 @@ constructor(
 
                 class Builder {
 
-                    private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -26132,31 +34267,48 @@ constructor(
                     }
 
                     fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                        apply {
-                            this.bulkWithProrationConfig = bulkWithProrationConfig
-                        }
+                        bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                    fun bulkWithProrationConfig(
+                        bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                    ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -26165,13 +34317,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -26188,13 +34347,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -26204,12 +34371,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -26224,22 +34398,32 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
-                    /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
                     }
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
+
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -26256,22 +34440,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -26281,12 +34480,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -26295,6 +34502,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -26352,6 +34566,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -26557,22 +34779,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -26582,8 +34828,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -26597,10 +34843,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -26721,22 +34974,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -26746,8 +35023,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -26762,10 +35039,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -26895,6 +35179,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -26976,94 +35268,215 @@ constructor(
             class NewFloatingGroupedTieredPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("currency") private val currency: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("grouped_tiered_package_config")
-                private val groupedTieredPackageConfig: GroupedTieredPackageConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** An ISO 4217 currency string for which this price is billed in. */
-                @JsonProperty("currency") fun currency(): String = currency
+                fun currency(): String = currency.getRequired("currency")
 
-                @JsonProperty("grouped_tiered_package_config")
                 fun groupedTieredPackageConfig(): GroupedTieredPackageConfig =
+                    groupedTieredPackageConfig.getRequired("grouped_tiered_package_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** An ISO 4217 currency string for which this price is billed in. */
+                @JsonProperty("currency")
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
+
+                @JsonProperty("grouped_tiered_package_config")
+                @ExcludeMissing
+                fun _groupedTieredPackageConfig(): JsonField<GroupedTieredPackageConfig> =
                     groupedTieredPackageConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -27071,12 +35484,36 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewFloatingGroupedTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        currency()
+                        groupedTieredPackageConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -27086,21 +35523,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var currency: String? = null
-                    private var groupedTieredPackageConfig: GroupedTieredPackageConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var currency: JsonField<String>? = null
+                    private var groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>? =
+                        null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -27130,30 +35571,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** An ISO 4217 currency string for which this price is billed in. */
+                    fun currency(currency: String) = currency(JsonField.of(currency))
 
                     /** An ISO 4217 currency string for which this price is billed in. */
-                    fun currency(currency: String) = apply { this.currency = currency }
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
 
                     fun groupedTieredPackageConfig(
                         groupedTieredPackageConfig: GroupedTieredPackageConfig
+                    ) = groupedTieredPackageConfig(JsonField.of(groupedTieredPackageConfig))
+
+                    fun groupedTieredPackageConfig(
+                        groupedTieredPackageConfig: JsonField<GroupedTieredPackageConfig>
                     ) = apply { this.groupedTieredPackageConfig = groupedTieredPackageConfig }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -27162,13 +35622,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -27185,13 +35652,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -27201,12 +35676,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -27217,26 +35699,36 @@ constructor(
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun conversionRate(conversionRate: Optional<Double>) =
-                        conversionRate(conversionRate.orElse(null) as Double?)
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun conversionRate(conversionRate: Optional<Double>) =
+                        conversionRate(conversionRate.orElse(null) as Double?)
+
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
 
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -27253,22 +35745,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -27278,12 +35785,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -27292,6 +35807,13 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -27431,6 +35953,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedTieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27554,22 +36084,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27579,8 +36133,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27594,10 +36148,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27718,22 +36279,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27743,8 +36328,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27759,10 +36344,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27892,6 +36484,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27992,32 +36592,68 @@ constructor(
     class AddAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment") private val adjustment: Adjustment,
-        @JsonProperty("start_date") private val startDate: StartDate,
-        @JsonProperty("end_date") private val endDate: EndDate?,
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        private val adjustment: JsonField<Adjustment> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<StartDate> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<EndDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The definition of a new adjustment to create and add to the subscription. */
-        @JsonProperty("adjustment") fun adjustment(): Adjustment = adjustment
+        fun adjustment(): Adjustment = adjustment.getRequired("adjustment")
+
+        /**
+         * The start date of the adjustment interval. This is the date that the adjustment will
+         * start affecting prices on the subscription.
+         */
+        fun startDate(): StartDate = startDate.getRequired("start_date")
+
+        /**
+         * The end date of the adjustment interval. This is the date that the adjustment will stop
+         * affecting prices on the subscription.
+         */
+        fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The definition of a new adjustment to create and add to the subscription. */
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /**
          * The start date of the adjustment interval. This is the date that the adjustment will
          * start affecting prices on the subscription.
          */
-        @JsonProperty("start_date") fun startDate(): StartDate = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<StartDate> = startDate
 
         /**
          * The end date of the adjustment interval. This is the date that the adjustment will stop
          * affecting prices on the subscription.
          */
-        @JsonProperty("end_date") fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate)
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<EndDate> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddAdjustment = apply {
+            if (!validated) {
+                adjustment()
+                startDate()
+                endDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -28027,9 +36663,9 @@ constructor(
 
         class Builder {
 
-            private var adjustment: Adjustment? = null
-            private var startDate: StartDate? = null
-            private var endDate: EndDate? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var startDate: JsonField<StartDate>? = null
+            private var endDate: JsonField<EndDate> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -28041,47 +36677,50 @@ constructor(
             }
 
             /** The definition of a new adjustment to create and add to the subscription. */
-            fun adjustment(adjustment: Adjustment) = apply { this.adjustment = adjustment }
+            fun adjustment(adjustment: Adjustment) = adjustment(JsonField.of(adjustment))
 
-            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewPercentageDiscount(newPercentageDiscount)
+            /** The definition of a new adjustment to create and add to the subscription. */
+            fun adjustment(adjustment: JsonField<Adjustment>) = apply {
+                this.adjustment = adjustment
             }
 
-            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewUsageDiscount(newUsageDiscount)
-            }
+            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) =
+                adjustment(Adjustment.ofNewPercentageDiscount(newPercentageDiscount))
 
-            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) = apply {
-                this.adjustment = Adjustment.ofNewAmountDiscount(newAmountDiscount)
-            }
+            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) =
+                adjustment(Adjustment.ofNewUsageDiscount(newUsageDiscount))
 
-            fun adjustment(newMinimum: Adjustment.NewMinimum) = apply {
-                this.adjustment = Adjustment.ofNewMinimum(newMinimum)
-            }
+            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) =
+                adjustment(Adjustment.ofNewAmountDiscount(newAmountDiscount))
 
-            fun adjustment(newMaximum: Adjustment.NewMaximum) = apply {
-                this.adjustment = Adjustment.ofNewMaximum(newMaximum)
-            }
+            fun adjustment(newMinimum: Adjustment.NewMinimum) =
+                adjustment(Adjustment.ofNewMinimum(newMinimum))
+
+            fun adjustment(newMaximum: Adjustment.NewMaximum) =
+                adjustment(Adjustment.ofNewMaximum(newMaximum))
 
             /**
              * The start date of the adjustment interval. This is the date that the adjustment will
              * start affecting prices on the subscription.
              */
-            fun startDate(startDate: StartDate) = apply { this.startDate = startDate }
+            fun startDate(startDate: StartDate) = startDate(JsonField.of(startDate))
 
-            fun startDate(dateTime: OffsetDateTime) = apply {
-                this.startDate = StartDate.ofDateTime(dateTime)
-            }
+            /**
+             * The start date of the adjustment interval. This is the date that the adjustment will
+             * start affecting prices on the subscription.
+             */
+            fun startDate(startDate: JsonField<StartDate>) = apply { this.startDate = startDate }
 
-            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.startDate = StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun startDate(dateTime: OffsetDateTime) = startDate(StartDate.ofDateTime(dateTime))
+
+            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                startDate(StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
              * stop affecting prices on the subscription.
              */
-            fun endDate(endDate: EndDate?) = apply { this.endDate = endDate }
+            fun endDate(endDate: EndDate?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
@@ -28089,13 +36728,16 @@ constructor(
              */
             fun endDate(endDate: Optional<EndDate>) = endDate(endDate.orElse(null))
 
-            fun endDate(dateTime: OffsetDateTime) = apply {
-                this.endDate = EndDate.ofDateTime(dateTime)
-            }
+            /**
+             * The end date of the adjustment interval. This is the date that the adjustment will
+             * stop affecting prices on the subscription.
+             */
+            fun endDate(endDate: JsonField<EndDate>) = apply { this.endDate = endDate }
 
-            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.endDate = EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun endDate(dateTime: OffsetDateTime) = endDate(EndDate.ofDateTime(dateTime))
+
+            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                endDate(EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -28138,6 +36780,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newPercentageDiscount(): Optional<NewPercentageDiscount> =
                 Optional.ofNullable(newPercentageDiscount)
 
@@ -28188,6 +36832,26 @@ constructor(
                 }
             }
 
+            fun validate(): Adjustment = apply {
+                if (!validated) {
+                    if (
+                        newPercentageDiscount == null &&
+                            newUsageDiscount == null &&
+                            newAmountDiscount == null &&
+                            newMinimum == null &&
+                            newMaximum == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Adjustment: $_json")
+                    }
+                    newPercentageDiscount?.validate()
+                    newUsageDiscount?.validate()
+                    newAmountDiscount?.validate()
+                    newMinimum?.validate()
+                    newMaximum?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -28257,29 +36921,40 @@ constructor(
 
                     when (adjustmentType) {
                         "percentage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>())?.let {
-                                return Adjustment(newPercentageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newPercentageDiscount = it, _json = json)
+                                }
                         }
                         "usage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>())?.let {
-                                return Adjustment(newUsageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newUsageDiscount = it, _json = json)
+                                }
                         }
                         "amount_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>())?.let {
-                                return Adjustment(newAmountDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newAmountDiscount = it, _json = json)
+                                }
                         }
                         "minimum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMinimum>())?.let {
-                                return Adjustment(newMinimum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMinimum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMinimum = it, _json = json)
+                                }
                         }
                         "maximum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMaximum>())?.let {
-                                return Adjustment(newMaximum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMaximum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMaximum = it, _json = json)
+                                }
                         }
                     }
 
@@ -28313,35 +36988,75 @@ constructor(
             class NewPercentageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewPercentageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        percentageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28351,47 +37066,58 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var percentageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newPercentageDiscount: NewPercentageDiscount) = apply {
                         adjustmentType = newPercentageDiscount.adjustmentType
-                        appliesToPriceIds = newPercentageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newPercentageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         percentageDiscount = newPercentageDiscount.percentageDiscount
                         isInvoiceLevel = newPercentageDiscount.isInvoiceLevel
                         additionalProperties =
                             newPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
-                        this.percentageDiscount = percentageDiscount
-                    }
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                        this.percentageDiscount = percentageDiscount
                     }
 
                     /**
@@ -28399,15 +37125,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -28439,7 +37165,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(percentageDiscount) {
                                 "`percentageDiscount` is required but was not set"
                             },
@@ -28522,34 +37248,74 @@ constructor(
             class NewUsageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewUsageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        usageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28559,46 +37325,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var usageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var usageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newUsageDiscount: NewUsageDiscount) = apply {
                         adjustmentType = newUsageDiscount.adjustmentType
-                        appliesToPriceIds = newUsageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newUsageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         usageDiscount = newUsageDiscount.usageDiscount
                         isInvoiceLevel = newUsageDiscount.isInvoiceLevel
                         additionalProperties = newUsageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun usageDiscount(usageDiscount: Double) = apply {
-                        this.usageDiscount = usageDiscount
-                    }
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                        this.usageDiscount = usageDiscount
                     }
 
                     /**
@@ -28606,15 +37383,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -28646,7 +37423,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(usageDiscount) {
                                 "`usageDiscount` is required but was not set"
                             },
@@ -28729,34 +37506,74 @@ constructor(
             class NewAmountDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("amount_discount") private val amountDiscount: String,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
-                @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewAmountDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        amountDiscount()
+                        appliesToPriceIds()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28766,46 +37583,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var amountDiscount: String? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newAmountDiscount: NewAmountDiscount) = apply {
                         adjustmentType = newAmountDiscount.adjustmentType
                         amountDiscount = newAmountDiscount.amountDiscount
-                        appliesToPriceIds = newAmountDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newAmountDiscount.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = newAmountDiscount.isInvoiceLevel
                         additionalProperties = newAmountDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
-                    fun amountDiscount(amountDiscount: String) = apply {
+                    fun amountDiscount(amountDiscount: String) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
-                    }
-
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -28813,15 +37641,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -28856,7 +37684,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             isInvoiceLevel,
                             additionalProperties.toImmutable(),
                         )
@@ -28936,38 +37764,84 @@ constructor(
             class NewMinimum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /** The item ID that revenue from this minimum will be attributed to. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMinimum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        itemId()
+                        minimumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28977,51 +37851,64 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var itemId: String? = null
-                    private var minimumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMinimum: NewMinimum) = apply {
                         adjustmentType = newMinimum.adjustmentType
-                        appliesToPriceIds = newMinimum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMinimum.appliesToPriceIds.map { it.toMutableList() }
                         itemId = newMinimum.itemId
                         minimumAmount = newMinimum.minimumAmount
                         isInvoiceLevel = newMinimum.isInvoiceLevel
                         additionalProperties = newMinimum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /** The item ID that revenue from this minimum will be attributed to. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun minimumAmount(minimumAmount: String) = apply {
-                        this.minimumAmount = minimumAmount
-                    }
+                    /** The item ID that revenue from this minimum will be attributed to. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                        this.minimumAmount = minimumAmount
                     }
 
                     /**
@@ -29029,15 +37916,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -29069,7 +37956,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(itemId) { "`itemId` is required but was not set" },
                             checkNotNull(minimumAmount) {
                                 "`minimumAmount` is required but was not set"
@@ -29153,34 +38040,74 @@ constructor(
             class NewMaximum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("maximum_amount") private val maximumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun maximumAmount(): String = maximumAmount.getRequired("maximum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("maximum_amount") fun maximumAmount(): String = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMaximum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        maximumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -29190,46 +38117,56 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var maximumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMaximum: NewMaximum) = apply {
                         adjustmentType = newMaximum.adjustmentType
-                        appliesToPriceIds = newMaximum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMaximum.appliesToPriceIds.map { it.toMutableList() }
                         maximumAmount = newMaximum.maximumAmount
                         isInvoiceLevel = newMaximum.isInvoiceLevel
                         additionalProperties = newMaximum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun maximumAmount(maximumAmount: String) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String) =
+                        maximumAmount(JsonField.of(maximumAmount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
                     /**
@@ -29237,15 +38174,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -29277,7 +38214,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(maximumAmount) {
                                 "`maximumAmount` is required but was not set"
                             },
@@ -29370,6 +38307,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -29395,6 +38334,15 @@ constructor(
                 }
             }
 
+            fun validate(): StartDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown StartDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -29483,6 +38431,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -29508,6 +38458,15 @@ constructor(
                 }
             }
 
+            fun validate(): EndDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown EndDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -29605,18 +38564,63 @@ constructor(
     class Edit
     @JsonCreator
     private constructor(
-        @JsonProperty("price_interval_id") private val priceIntervalId: String,
-        @JsonProperty("billing_cycle_day") private val billingCycleDay: Long?,
-        @JsonProperty("end_date") private val endDate: EndDate?,
+        @JsonProperty("price_interval_id")
+        @ExcludeMissing
+        private val priceIntervalId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        private val billingCycleDay: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<EndDate> = JsonMissing.of(),
         @JsonProperty("fixed_fee_quantity_transitions")
-        private val fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?,
-        @JsonProperty("start_date") private val startDate: StartDate?,
+        @ExcludeMissing
+        private val fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
+            JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<StartDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The id of the price interval to edit. */
-        @JsonProperty("price_interval_id") fun priceIntervalId(): String = priceIntervalId
+        fun priceIntervalId(): String = priceIntervalId.getRequired("price_interval_id")
+
+        /**
+         * The updated billing cycle day for this price interval. If not specified, the billing
+         * cycle day will not be updated. Note that overlapping price intervals must have the same
+         * billing cycle day.
+         */
+        fun billingCycleDay(): Optional<Long> =
+            Optional.ofNullable(billingCycleDay.getNullable("billing_cycle_day"))
+
+        /**
+         * The updated end date of this price interval. If not specified, the start date will not be
+         * updated.
+         */
+        fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /**
+         * A list of fixed fee quantity transitions to use for this price interval. Note that this
+         * list will overwrite all existing fixed fee quantity transitions on the price interval.
+         */
+        fun fixedFeeQuantityTransitions(): Optional<List<FixedFeeQuantityTransition>> =
+            Optional.ofNullable(
+                fixedFeeQuantityTransitions.getNullable("fixed_fee_quantity_transitions")
+            )
+
+        /**
+         * The updated start date of this price interval. If not specified, the start date will not
+         * be updated.
+         */
+        fun startDate(): Optional<StartDate> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
+        /** The id of the price interval to edit. */
+        @JsonProperty("price_interval_id")
+        @ExcludeMissing
+        fun _priceIntervalId(): JsonField<String> = priceIntervalId
 
         /**
          * The updated billing cycle day for this price interval. If not specified, the billing
@@ -29624,33 +38628,49 @@ constructor(
          * billing cycle day.
          */
         @JsonProperty("billing_cycle_day")
-        fun billingCycleDay(): Optional<Long> = Optional.ofNullable(billingCycleDay)
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The updated end date of this price interval. If not specified, the start date will not be
          * updated.
          */
-        @JsonProperty("end_date") fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate)
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<EndDate> = endDate
 
         /**
          * A list of fixed fee quantity transitions to use for this price interval. Note that this
          * list will overwrite all existing fixed fee quantity transitions on the price interval.
          */
         @JsonProperty("fixed_fee_quantity_transitions")
-        fun fixedFeeQuantityTransitions(): Optional<List<FixedFeeQuantityTransition>> =
-            Optional.ofNullable(fixedFeeQuantityTransitions)
+        @ExcludeMissing
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The updated start date of this price interval. If not specified, the start date will not
          * be updated.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<StartDate> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<StartDate> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Edit = apply {
+            if (!validated) {
+                priceIntervalId()
+                billingCycleDay()
+                endDate()
+                fixedFeeQuantityTransitions().map { it.forEach { it.validate() } }
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -29660,11 +38680,13 @@ constructor(
 
         class Builder {
 
-            private var priceIntervalId: String? = null
-            private var billingCycleDay: Long? = null
-            private var endDate: EndDate? = null
-            private var fixedFeeQuantityTransitions: MutableList<FixedFeeQuantityTransition>? = null
-            private var startDate: StartDate? = null
+            private var priceIntervalId: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
+            private var endDate: JsonField<EndDate> = JsonMissing.of()
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var startDate: JsonField<StartDate> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -29672,13 +38694,18 @@ constructor(
                 priceIntervalId = edit.priceIntervalId
                 billingCycleDay = edit.billingCycleDay
                 endDate = edit.endDate
-                fixedFeeQuantityTransitions = edit.fixedFeeQuantityTransitions?.toMutableList()
+                fixedFeeQuantityTransitions =
+                    edit.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 startDate = edit.startDate
                 additionalProperties = edit.additionalProperties.toMutableMap()
             }
 
             /** The id of the price interval to edit. */
-            fun priceIntervalId(priceIntervalId: String) = apply {
+            fun priceIntervalId(priceIntervalId: String) =
+                priceIntervalId(JsonField.of(priceIntervalId))
+
+            /** The id of the price interval to edit. */
+            fun priceIntervalId(priceIntervalId: JsonField<String>) = apply {
                 this.priceIntervalId = priceIntervalId
             }
 
@@ -29687,9 +38714,8 @@ constructor(
              * cycle day will not be updated. Note that overlapping price intervals must have the
              * same billing cycle day.
              */
-            fun billingCycleDay(billingCycleDay: Long?) = apply {
-                this.billingCycleDay = billingCycleDay
-            }
+            fun billingCycleDay(billingCycleDay: Long?) =
+                billingCycleDay(JsonField.ofNullable(billingCycleDay))
 
             /**
              * The updated billing cycle day for this price interval. If not specified, the billing
@@ -29707,11 +38733,20 @@ constructor(
             fun billingCycleDay(billingCycleDay: Optional<Long>) =
                 billingCycleDay(billingCycleDay.orElse(null) as Long?)
 
+            /**
+             * The updated billing cycle day for this price interval. If not specified, the billing
+             * cycle day will not be updated. Note that overlapping price intervals must have the
+             * same billing cycle day.
+             */
+            fun billingCycleDay(billingCycleDay: JsonField<Long>) = apply {
+                this.billingCycleDay = billingCycleDay
+            }
+
             /**
              * The updated end date of this price interval. If not specified, the start date will
              * not be updated.
              */
-            fun endDate(endDate: EndDate?) = apply { this.endDate = endDate }
+            fun endDate(endDate: EndDate?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The updated end date of this price interval. If not specified, the start date will
@@ -29719,13 +38754,16 @@ constructor(
              */
             fun endDate(endDate: Optional<EndDate>) = endDate(endDate.orElse(null))
 
-            fun endDate(dateTime: OffsetDateTime) = apply {
-                this.endDate = EndDate.ofDateTime(dateTime)
-            }
+            /**
+             * The updated end date of this price interval. If not specified, the start date will
+             * not be updated.
+             */
+            fun endDate(endDate: JsonField<EndDate>) = apply { this.endDate = endDate }
 
-            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.endDate = EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun endDate(dateTime: OffsetDateTime) = endDate(EndDate.ofDateTime(dateTime))
+
+            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                endDate(EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             /**
              * A list of fixed fee quantity transitions to use for this price interval. Note that
@@ -29734,9 +38772,7 @@ constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
-            ) = apply {
-                this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions?.toMutableList()
-            }
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
 
             /**
              * A list of fixed fee quantity transitions to use for this price interval. Note that
@@ -29747,6 +38783,18 @@ constructor(
                 fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
             ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
+            /**
+             * A list of fixed fee quantity transitions to use for this price interval. Note that
+             * this list will overwrite all existing fixed fee quantity transitions on the price
+             * interval.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
             /**
              * A list of fixed fee quantity transitions to use for this price interval. Note that
              * this list will overwrite all existing fixed fee quantity transitions on the price
@@ -29756,8 +38804,14 @@ constructor(
                 fixedFeeQuantityTransition: FixedFeeQuantityTransition
             ) = apply {
                 fixedFeeQuantityTransitions =
-                    (fixedFeeQuantityTransitions ?: mutableListOf()).apply {
-                        add(fixedFeeQuantityTransition)
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
                     }
             }
 
@@ -29765,21 +38819,18 @@ constructor(
              * The updated start date of this price interval. If not specified, the start date will
              * not be updated.
              */
-            fun startDate(startDate: StartDate?) = apply { this.startDate = startDate }
+            fun startDate(startDate: StartDate) = startDate(JsonField.of(startDate))
 
             /**
              * The updated start date of this price interval. If not specified, the start date will
              * not be updated.
              */
-            fun startDate(startDate: Optional<StartDate>) = startDate(startDate.orElse(null))
+            fun startDate(startDate: JsonField<StartDate>) = apply { this.startDate = startDate }
 
-            fun startDate(dateTime: OffsetDateTime) = apply {
-                this.startDate = StartDate.ofDateTime(dateTime)
-            }
+            fun startDate(dateTime: OffsetDateTime) = startDate(StartDate.ofDateTime(dateTime))
 
-            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.startDate = StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                startDate(StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -29807,7 +38858,7 @@ constructor(
                     },
                     billingCycleDay,
                     endDate,
-                    fixedFeeQuantityTransitions?.toImmutable(),
+                    (fixedFeeQuantityTransitions ?: JsonMissing.of()).map { it.toImmutable() },
                     startDate,
                     additionalProperties.toImmutable(),
                 )
@@ -29826,6 +38877,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -29851,6 +38904,15 @@ constructor(
                 }
             }
 
+            fun validate(): EndDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown EndDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -29930,22 +38992,44 @@ constructor(
         class FixedFeeQuantityTransition
         @JsonCreator
         private constructor(
-            @JsonProperty("effective_date") private val effectiveDate: OffsetDateTime,
-            @JsonProperty("quantity") private val quantity: Long,
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            private val effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+            @JsonProperty("quantity")
+            @ExcludeMissing
+            private val quantity: JsonField<Long> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
             /** The date that the fixed fee quantity transition should take effect. */
-            @JsonProperty("effective_date") fun effectiveDate(): OffsetDateTime = effectiveDate
+            fun effectiveDate(): OffsetDateTime = effectiveDate.getRequired("effective_date")
+
+            /** The quantity of the fixed fee quantity transition. */
+            fun quantity(): Long = quantity.getRequired("quantity")
+
+            /** The date that the fixed fee quantity transition should take effect. */
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
             /** The quantity of the fixed fee quantity transition. */
-            @JsonProperty("quantity") fun quantity(): Long = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): FixedFeeQuantityTransition = apply {
+                if (!validated) {
+                    effectiveDate()
+                    quantity()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -29955,8 +39039,8 @@ constructor(
 
             class Builder {
 
-                private var effectiveDate: OffsetDateTime? = null
-                private var quantity: Long? = null
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -29968,12 +39052,19 @@ constructor(
                 }
 
                 /** The date that the fixed fee quantity transition should take effect. */
-                fun effectiveDate(effectiveDate: OffsetDateTime) = apply {
+                fun effectiveDate(effectiveDate: OffsetDateTime) =
+                    effectiveDate(JsonField.of(effectiveDate))
+
+                /** The date that the fixed fee quantity transition should take effect. */
+                fun effectiveDate(effectiveDate: JsonField<OffsetDateTime>) = apply {
                     this.effectiveDate = effectiveDate
                 }
 
                 /** The quantity of the fixed fee quantity transition. */
-                fun quantity(quantity: Long) = apply { this.quantity = quantity }
+                fun quantity(quantity: Long) = quantity(JsonField.of(quantity))
+
+                /** The quantity of the fixed fee quantity transition. */
+                fun quantity(quantity: JsonField<Long>) = apply { this.quantity = quantity }
 
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
@@ -30038,6 +39129,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -30063,6 +39156,15 @@ constructor(
                 }
             }
 
+            fun validate(): StartDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown StartDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -30160,34 +39262,70 @@ constructor(
     class EditAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment_interval_id") private val adjustmentIntervalId: String,
-        @JsonProperty("end_date") private val endDate: EndDate?,
-        @JsonProperty("start_date") private val startDate: StartDate?,
+        @JsonProperty("adjustment_interval_id")
+        @ExcludeMissing
+        private val adjustmentIntervalId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<EndDate> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<StartDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /** The id of the adjustment interval to edit. */
+        fun adjustmentIntervalId(): String =
+            adjustmentIntervalId.getRequired("adjustment_interval_id")
+
+        /**
+         * The updated end date of this adjustment interval. If not specified, the start date will
+         * not be updated.
+         */
+        fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /**
+         * The updated start date of this adjustment interval. If not specified, the start date will
+         * not be updated.
+         */
+        fun startDate(): Optional<StartDate> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
         /** The id of the adjustment interval to edit. */
         @JsonProperty("adjustment_interval_id")
-        fun adjustmentIntervalId(): String = adjustmentIntervalId
+        @ExcludeMissing
+        fun _adjustmentIntervalId(): JsonField<String> = adjustmentIntervalId
 
         /**
          * The updated end date of this adjustment interval. If not specified, the start date will
          * not be updated.
          */
-        @JsonProperty("end_date") fun endDate(): Optional<EndDate> = Optional.ofNullable(endDate)
+        @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<EndDate> = endDate
 
         /**
          * The updated start date of this adjustment interval. If not specified, the start date will
          * not be updated.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<StartDate> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<StartDate> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): EditAdjustment = apply {
+            if (!validated) {
+                adjustmentIntervalId()
+                endDate()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -30197,9 +39335,9 @@ constructor(
 
         class Builder {
 
-            private var adjustmentIntervalId: String? = null
-            private var endDate: EndDate? = null
-            private var startDate: StartDate? = null
+            private var adjustmentIntervalId: JsonField<String>? = null
+            private var endDate: JsonField<EndDate> = JsonMissing.of()
+            private var startDate: JsonField<StartDate> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -30211,7 +39349,11 @@ constructor(
             }
 
             /** The id of the adjustment interval to edit. */
-            fun adjustmentIntervalId(adjustmentIntervalId: String) = apply {
+            fun adjustmentIntervalId(adjustmentIntervalId: String) =
+                adjustmentIntervalId(JsonField.of(adjustmentIntervalId))
+
+            /** The id of the adjustment interval to edit. */
+            fun adjustmentIntervalId(adjustmentIntervalId: JsonField<String>) = apply {
                 this.adjustmentIntervalId = adjustmentIntervalId
             }
 
@@ -30219,7 +39361,7 @@ constructor(
              * The updated end date of this adjustment interval. If not specified, the start date
              * will not be updated.
              */
-            fun endDate(endDate: EndDate?) = apply { this.endDate = endDate }
+            fun endDate(endDate: EndDate?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The updated end date of this adjustment interval. If not specified, the start date
@@ -30227,33 +39369,33 @@ constructor(
              */
             fun endDate(endDate: Optional<EndDate>) = endDate(endDate.orElse(null))
 
-            fun endDate(dateTime: OffsetDateTime) = apply {
-                this.endDate = EndDate.ofDateTime(dateTime)
-            }
+            /**
+             * The updated end date of this adjustment interval. If not specified, the start date
+             * will not be updated.
+             */
+            fun endDate(endDate: JsonField<EndDate>) = apply { this.endDate = endDate }
 
-            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.endDate = EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun endDate(dateTime: OffsetDateTime) = endDate(EndDate.ofDateTime(dateTime))
+
+            fun endDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                endDate(EndDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             /**
              * The updated start date of this adjustment interval. If not specified, the start date
              * will not be updated.
              */
-            fun startDate(startDate: StartDate?) = apply { this.startDate = startDate }
+            fun startDate(startDate: StartDate) = startDate(JsonField.of(startDate))
 
             /**
              * The updated start date of this adjustment interval. If not specified, the start date
              * will not be updated.
              */
-            fun startDate(startDate: Optional<StartDate>) = startDate(startDate.orElse(null))
+            fun startDate(startDate: JsonField<StartDate>) = apply { this.startDate = startDate }
 
-            fun startDate(dateTime: OffsetDateTime) = apply {
-                this.startDate = StartDate.ofDateTime(dateTime)
-            }
+            fun startDate(dateTime: OffsetDateTime) = startDate(StartDate.ofDateTime(dateTime))
 
-            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) = apply {
-                this.startDate = StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate)
-            }
+            fun startDate(billingCycleRelativeDate: BillingCycleRelativeDate) =
+                startDate(StartDate.ofBillingCycleRelativeDate(billingCycleRelativeDate))
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -30298,6 +39440,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -30323,6 +39467,15 @@ constructor(
                 }
             }
 
+            fun validate(): EndDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown EndDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -30411,6 +39564,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun dateTime(): Optional<OffsetDateTime> = Optional.ofNullable(dateTime)
 
             fun billingCycleRelativeDate(): Optional<BillingCycleRelativeDate> =
@@ -30436,6 +39591,15 @@ constructor(
                 }
             }
 
+            fun validate(): StartDate = apply {
+                if (!validated) {
+                    if (dateTime == null && billingCycleRelativeDate == null) {
+                        throw OrbInvalidDataException("Unknown StartDate: $_json")
+                    }
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsResponse.kt
index 4c628942..91e00699 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionPriceIntervalsResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -453,7 +473,10 @@ private constructor(
             apply {
                 id = subscriptionPriceIntervalsResponse.id
                 activePlanPhaseOrder = subscriptionPriceIntervalsResponse.activePlanPhaseOrder
-                adjustmentIntervals = subscriptionPriceIntervalsResponse.adjustmentIntervals
+                adjustmentIntervals =
+                    subscriptionPriceIntervalsResponse.adjustmentIntervals.map {
+                        it.toMutableList()
+                    }
                 autoCollection = subscriptionPriceIntervalsResponse.autoCollection
                 billingCycleAnchorConfiguration =
                     subscriptionPriceIntervalsResponse.billingCycleAnchorConfiguration
@@ -465,17 +488,23 @@ private constructor(
                     subscriptionPriceIntervalsResponse.currentBillingPeriodStartDate
                 customer = subscriptionPriceIntervalsResponse.customer
                 defaultInvoiceMemo = subscriptionPriceIntervalsResponse.defaultInvoiceMemo
-                discountIntervals = subscriptionPriceIntervalsResponse.discountIntervals
+                discountIntervals =
+                    subscriptionPriceIntervalsResponse.discountIntervals.map { it.toMutableList() }
                 endDate = subscriptionPriceIntervalsResponse.endDate
                 fixedFeeQuantitySchedule =
-                    subscriptionPriceIntervalsResponse.fixedFeeQuantitySchedule
+                    subscriptionPriceIntervalsResponse.fixedFeeQuantitySchedule.map {
+                        it.toMutableList()
+                    }
                 invoicingThreshold = subscriptionPriceIntervalsResponse.invoicingThreshold
-                maximumIntervals = subscriptionPriceIntervalsResponse.maximumIntervals
+                maximumIntervals =
+                    subscriptionPriceIntervalsResponse.maximumIntervals.map { it.toMutableList() }
                 metadata = subscriptionPriceIntervalsResponse.metadata
-                minimumIntervals = subscriptionPriceIntervalsResponse.minimumIntervals
+                minimumIntervals =
+                    subscriptionPriceIntervalsResponse.minimumIntervals.map { it.toMutableList() }
                 netTerms = subscriptionPriceIntervalsResponse.netTerms
                 plan = subscriptionPriceIntervalsResponse.plan
-                priceIntervals = subscriptionPriceIntervalsResponse.priceIntervals
+                priceIntervals =
+                    subscriptionPriceIntervalsResponse.priceIntervals.map { it.toMutableList() }
                 redeemedCoupon = subscriptionPriceIntervalsResponse.redeemedCoupon
                 startDate = subscriptionPriceIntervalsResponse.startDate
                 status = subscriptionPriceIntervalsResponse.status
@@ -488,9 +517,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -503,15 +541,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -557,8 +626,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -575,8 +652,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -631,8 +716,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -648,11 +740,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
         }
 
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
+        }
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -662,10 +771,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
+
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -677,7 +805,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -700,7 +842,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -739,11 +895,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -784,31 +957,55 @@ private constructor(
 
         fun build(): SubscriptionPriceIntervalsResponse =
             SubscriptionPriceIntervalsResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -849,20 +1046,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -890,18 +1093,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -917,6 +1121,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -924,11 +1143,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -962,11 +1199,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1269,11 +1509,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1281,12 +1521,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1294,15 +1534,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1332,13 +1572,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1346,7 +1586,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1386,7 +1627,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1404,9 +1659,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1414,7 +1678,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1443,13 +1710,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1581,16 +1859,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1598,7 +1876,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1606,15 +1884,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1644,13 +1922,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1658,7 +1936,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1684,7 +1965,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1717,9 +2012,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1727,7 +2031,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1756,13 +2063,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1893,16 +2211,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1910,21 +2228,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1954,20 +2274,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1993,7 +2314,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2011,9 +2346,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2021,7 +2365,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2065,13 +2412,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2208,16 +2566,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2225,24 +2583,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2273,21 +2633,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2313,7 +2674,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2352,9 +2727,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2362,7 +2746,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2391,14 +2778,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2529,16 +2927,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2546,21 +2944,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2590,20 +2990,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2628,7 +3029,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2661,9 +3076,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2671,7 +3095,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2700,13 +3127,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2839,19 +3277,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2877,7 +3315,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2912,7 +3350,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2924,7 +3375,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2953,7 +3417,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3205,25 +3669,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3252,19 +3724,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3287,7 +3761,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3297,9 +3785,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3308,7 +3811,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3345,12 +3851,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3473,25 +3987,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3520,18 +4040,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3546,7 +4070,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3556,9 +4094,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3567,7 +4120,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3617,12 +4173,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3748,26 +4312,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3796,18 +4368,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3821,7 +4395,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3831,9 +4419,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3842,7 +4445,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3894,12 +4500,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4003,13 +4617,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4036,10 +4654,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4051,7 +4669,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4090,10 +4710,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4163,24 +4783,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4208,17 +4834,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4231,7 +4858,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4241,11 +4882,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4293,11 +4952,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4447,24 +5112,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4492,17 +5163,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4515,7 +5187,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4525,11 +5211,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4577,11 +5281,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4916,10 +5626,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4928,7 +5640,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4937,13 +5649,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4951,7 +5666,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5181,13 +5897,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5218,15 +5936,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5236,7 +5955,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5260,8 +5980,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5277,8 +6005,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5293,7 +6030,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5306,8 +6049,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5315,7 +6066,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5777,6 +6550,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5812,14 +6650,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5847,11 +6694,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5877,9 +6726,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5930,9 +6779,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5997,11 +6848,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6027,9 +6882,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6044,7 +6899,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6075,9 +6932,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6177,7 +7034,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6201,7 +7060,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6210,7 +7069,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6233,7 +7094,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeParams.kt
index 90a5609a..d305ac54 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -31,6 +32,164 @@ import java.util.Objects
 import java.util.Optional
 import kotlin.jvm.optionals.getOrNull
 
+/**
+ * This endpoint can be used to change an existing subscription's plan. It returns the serialized
+ * updated subscription object.
+ *
+ * The body parameter `change_option` determines when the plan change occurrs. Orb supports three
+ * options:
+ * - `end_of_subscription_term`: changes the plan at the end of the existing plan's term.
+ *     - Issuing this plan change request for a monthly subscription will keep the existing plan
+ *       active until the start of the subsequent month. Issuing this plan change request for a
+ *       yearly subscription will keep the existing plan active for the full year. Charges incurred
+ *       in the remaining period will be invoiced as normal.
+ *     - Example: The plan is billed monthly on the 1st of the month, the request is made on January
+ *       15th, so the plan will be changed on February 1st, and invoice will be issued on February
+ *       1st for the last month of the original plan.
+ * - `immediate`: changes the plan immediately.
+ *     - Subscriptions that have their plan changed with this option will move to the new plan
+ *       immediately, and be invoiced immediately.
+ *     - This invoice will include any usage fees incurred in the billing period up to the change,
+ *       along with any prorated recurring fees for the billing period, if applicable.
+ *     - Example: The plan is billed monthly on the 1st of the month, the request is made on January
+ *       15th, so the plan will be changed on January 15th, and an invoice will be issued for the
+ *       partial month, from January 1 to January 15, on the original plan.
+ * - `requested_date`: changes the plan on the requested date (`change_date`).
+ *     - If no timezone is provided, the customer's timezone is used. The `change_date` body
+ *       parameter is required if this option is chosen.
+ *     - Example: The plan is billed monthly on the 1st of the month, the request is made on January
+ *       15th, with a requested `change_date` of February 15th, so the plan will be changed on
+ *       February 15th, and invoices will be issued on February 1st and February 15th.
+ *
+ * Note that one of `plan_id` or `external_plan_id` is required in the request body for this
+ * operation.
+ *
+ * ## Customize your customer's subscriptions
+ *
+ * Prices and adjustments in a plan can be added, removed, or replaced on the subscription when you
+ * schedule the plan change. This is useful when a customer has prices that differ from the default
+ * prices for a specific plan.
+ *
+ * :::info This feature is only available for accounts that have migrated to Subscription Overrides
+ * Version 2. You can find your Subscription Overrides Version at the bottom of your
+ * [Plans page](https://app.withorb.com/plans) :::
+ *
+ * ### Adding Prices
+ *
+ * To add prices, provide a list of objects with the key `add_prices`. An object in the list must
+ * specify an existing add-on price with a `price_id` or `external_price_id` field, or create a new
+ * add-on price by including an object with the key `price`, identical to what would be used in the
+ * request body for the [create price endpoint](../reference/create-price). See the
+ * [Price resource](../reference/price) for the specification of different price model
+ * configurations possible in this object.
+ *
+ * If the plan has phases, each object in the list must include a number with `plan_phase_order` key
+ * to indicate which phase the price should be added to.
+ *
+ * An object in the list can specify an optional `start_date` and optional `end_date`. This is
+ * equivalent to creating a price interval with the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals). If unspecified, the
+ * start or end date of the phase or subscription will be used.
+ *
+ * An object in the list can specify an optional `minimum_amount`, `maximum_amount`, or `discounts`.
+ * This will create adjustments which apply only to this price.
+ *
+ * Additionally, an object in the list can specify an optional `reference_id`. This ID can be used
+ * to reference this price when [adding an adjustment](#adding-adjustments) in the same API call.
+ * However the ID is _transient_ and cannot be used to refer to the price in future API calls.
+ *
+ * ### Removing Prices
+ *
+ * To remove prices, provide a list of objects with the key `remove_prices`. An object in the list
+ * must specify a plan price with either a `price_id` or `external_price_id` field.
+ *
+ * ### Replacing Prices
+ *
+ * To replace prices, provide a list of objects with the key `replace_prices`. An object in the list
+ * must specify a plan price to replace with the `replaces_price_id` key, and it must specify a
+ * price to replace it with by either referencing an existing add-on price with a `price_id` or
+ * `external_price_id` field, or by creating a new add-on price by including an object with the key
+ * `price`, identical to what would be used in the request body for the
+ * [create price endpoint](../reference/create-price). See the [Price resource](../reference/price)
+ * for the specification of different price model configurations possible in this object.
+ *
+ * For fixed fees, an object in the list can supply a `fixed_price_quantity` instead of a `price`,
+ * `price_id`, or `external_price_id` field. This will update only the quantity for the price,
+ * similar to the [Update price quantity](../reference/update-fixed-fee-quantity) endpoint.
+ *
+ * The replacement price will have the same phase, if applicable, and the same start and end dates
+ * as the price it replaces.
+ *
+ * An object in the list can specify an optional `minimum_amount`, `maximum_amount`, or `discounts`.
+ * This will create adjustments which apply only to this price.
+ *
+ * Additionally, an object in the list can specify an optional `reference_id`. This ID can be used
+ * to reference the replacement price when [adding an adjustment](#adding-adjustments) in the same
+ * API call. However the ID is _transient_ and cannot be used to refer to the price in future API
+ * calls.
+ *
+ * ### Adding adjustments
+ *
+ * To add adjustments, provide a list of objects with the key `add_adjustments`. An object in the
+ * list must include an object with the key `adjustment`, identical to the adjustment object in the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals).
+ *
+ * If the plan has phases, each object in the list must include a number with `plan_phase_order` key
+ * to indicate which phase the adjustment should be added to.
+ *
+ * An object in the list can specify an optional `start_date` and optional `end_date`. If
+ * unspecified, the start or end date of the phase or subscription will be used.
+ *
+ * ### Removing adjustments
+ *
+ * To remove adjustments, provide a list of objects with the key `remove_adjustments`. An object in
+ * the list must include a key, `adjustment_id`, with the ID of the adjustment to be removed.
+ *
+ * ### Replacing adjustments
+ *
+ * To replace adjustments, provide a list of objects with the key `replace_adjustments`. An object
+ * in the list must specify a plan adjustment to replace with the `replaces_adjustment_id` key, and
+ * it must specify an adjustment to replace it with by including an object with the key
+ * `adjustment`, identical to the adjustment object in the
+ * [add/edit price intervals endpoint](../reference/add-edit-price-intervals).
+ *
+ * The replacement adjustment will have the same phase, if applicable, and the same start and end
+ * dates as the adjustment it replaces.
+ *
+ * ## Price overrides (DEPRECATED)
+ *
+ * :::info Price overrides are being phased out in favor adding/removing/replacing prices. (See
+ * [Customize your customer's subscriptions](../reference/schedule-plan-change#customize-your-customers-subscriptions))
+ * :::
+ *
+ * Price overrides are used to update some or all prices in a plan for the specific subscription
+ * being created. This is useful when a new customer has negotiated a rate that is unique to the
+ * customer.
+ *
+ * To override prices, provide a list of objects with the key `price_overrides`. The price object in
+ * the list of overrides is expected to contain the existing price id, the `model_type` and
+ * configuration. (See the [Price resource](../reference/price) for the specification of different
+ * price model configurations.) The numerical values can be updated, but the billable metric,
+ * cadence, type, and name of a price can not be overridden.
+ *
+ * ### Maximums, and minimums
+ *
+ * Price overrides are used to update some or all prices in the target plan. Minimums and maximums,
+ * much like price overrides, can be useful when a new customer has negotiated a new or different
+ * minimum or maximum spend cap than the default for the plan. The request format for maximums and
+ * minimums is the same as those in [subscription creation](create-subscription).
+ *
+ * ## Scheduling multiple plan changes
+ *
+ * When scheduling multiple plan changes with the same date, the latest plan change on that day
+ * takes effect.
+ *
+ * ## Prorations for in-advance fees
+ *
+ * By default, Orb calculates the prorated difference in any fixed fees when making a plan change,
+ * adjusting the customer balance as needed. For details on this behavior, see
+ * [Modifying subscriptions](../guides/product-catalog/modifying-subscriptions.md#prorations-for-in-advance-fees).
+ */
 class SubscriptionSchedulePlanChangeParams
 constructor(
     private val subscriptionId: String,
@@ -174,12 +333,146 @@ constructor(
      */
     fun trialDurationDays(): Optional<Long> = body.trialDurationDays()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    fun _changeOption(): JsonField<ChangeOption> = body._changeOption()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Additional adjustments to be added to the subscription. (Only available for accounts that
+     * have migrated off of legacy subscription overrides)
+     */
+    fun _addAdjustments(): JsonField<List<AddAdjustment>> = body._addAdjustments()
+
+    /**
+     * Additional prices to be added to the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _addPrices(): JsonField<List<AddPrice>> = body._addPrices()
+
+    /**
+     * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned with
+     * the plan change's effective date.
+     */
+    fun _alignBillingWithPlanChangeDate(): JsonField<Boolean> =
+        body._alignBillingWithPlanChangeDate()
+
+    /**
+     * Determines whether issued invoices for this subscription will automatically be charged with
+     * the saved payment method on the due date. If not specified, this defaults to the behavior
+     * configured for this customer.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
+
+    /**
+     * Reset billing periods to be aligned with the plan change's effective date or start of the
+     * month. Defaults to `unchanged` which keeps subscription's existing billing cycle alignment.
+     */
+    fun _billingCycleAlignment(): JsonField<BillingCycleAlignment> = body._billingCycleAlignment()
+
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        body._billingCycleAnchorConfiguration()
+
+    /**
+     * The date that the plan change should take effect. This parameter can only be passed if the
+     * `change_option` is `requested_date`.
+     */
+    fun _changeDate(): JsonField<OffsetDateTime> = body._changeDate()
+
+    /**
+     * Redemption code to be used for this subscription. If the coupon cannot be found by its
+     * redemption code, or cannot be redeemed, an error response will be returned and the
+     * subscription creation or plan change will not be scheduled.
+     */
+    fun _couponRedemptionCode(): JsonField<String> = body._couponRedemptionCode()
+
+    fun _creditsOverageRate(): JsonField<Double> = body._creditsOverageRate()
+
+    /**
+     * Determines the default memo on this subscription's invoices. Note that if this is not
+     * provided, it is determined by the plan configuration.
+     */
+    fun _defaultInvoiceMemo(): JsonField<String> = body._defaultInvoiceMemo()
+
+    /**
+     * The external_plan_id of the plan that the given subscription should be switched to. Note that
+     * either this property or `plan_id` must be specified.
+     */
+    fun _externalPlanId(): JsonField<String> = body._externalPlanId()
+
+    /**
+     * An additional filter to apply to usage queries. This filter must be expressed as a boolean
+     * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If null,
+     * usage queries will not include any additional filter.
+     */
+    fun _filter(): JsonField<String> = body._filter()
+
+    /** The phase of the plan to start with */
+    fun _initialPhaseOrder(): JsonField<Long> = body._initialPhaseOrder()
+
+    /**
+     * When this subscription's accrued usage reaches this threshold, an invoice will be issued for
+     * the subscription. If not specified, invoices will only be issued at the end of the billing
+     * period.
+     */
+    fun _invoicingThreshold(): JsonField<String> = body._invoicingThreshold()
+
+    /**
+     * The net terms determines the difference between the invoice date and the issue date for the
+     * invoice. If you intend the invoice to be due on issue, set this to 0. If not provided, this
+     * defaults to the value specified in the plan.
+     */
+    fun _netTerms(): JsonField<Long> = body._netTerms()
+
+    fun _perCreditOverageAmount(): JsonField<Double> = body._perCreditOverageAmount()
+
+    /**
+     * The plan that the given subscription should be switched to. Note that either this property or
+     * `external_plan_id` must be specified.
+     */
+    fun _planId(): JsonField<String> = body._planId()
+
+    /**
+     * Specifies which version of the plan to change to. If null, the default version will be used.
+     */
+    fun _planVersionNumber(): JsonField<Long> = body._planVersionNumber()
+
+    /** Optionally provide a list of overrides for prices on the plan */
+    fun _priceOverrides(): JsonField<List<JsonValue>> = body._priceOverrides()
+
+    /**
+     * Plan adjustments to be removed from the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _removeAdjustments(): JsonField<List<RemoveAdjustment>> = body._removeAdjustments()
+
+    /**
+     * Plan prices to be removed from the subscription. (Only available for accounts that have
+     * migrated off of legacy subscription overrides)
+     */
+    fun _removePrices(): JsonField<List<RemovePrice>> = body._removePrices()
+
+    /**
+     * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+     * available for accounts that have migrated off of legacy subscription overrides)
+     */
+    fun _replaceAdjustments(): JsonField<List<ReplaceAdjustment>> = body._replaceAdjustments()
+
+    /**
+     * Plan prices to be replaced with additional prices on the subscription. (Only available for
+     * accounts that have migrated off of legacy subscription overrides)
+     */
+    fun _replacePrices(): JsonField<List<ReplacePrice>> = body._replacePrices()
+
+    /**
+     * The duration of the trial period in days. If not provided, this defaults to the value
+     * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+     */
+    fun _trialDurationDays(): JsonField<Long> = body._trialDurationDays()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionSchedulePlanChangeBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -197,62 +490,273 @@ constructor(
     class SubscriptionSchedulePlanChangeBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("change_option") private val changeOption: ChangeOption,
-        @JsonProperty("add_adjustments") private val addAdjustments: List<AddAdjustment>?,
-        @JsonProperty("add_prices") private val addPrices: List<AddPrice>?,
+        @JsonProperty("change_option")
+        @ExcludeMissing
+        private val changeOption: JsonField<ChangeOption> = JsonMissing.of(),
+        @JsonProperty("add_adjustments")
+        @ExcludeMissing
+        private val addAdjustments: JsonField<List<AddAdjustment>> = JsonMissing.of(),
+        @JsonProperty("add_prices")
+        @ExcludeMissing
+        private val addPrices: JsonField<List<AddPrice>> = JsonMissing.of(),
         @JsonProperty("align_billing_with_plan_change_date")
-        private val alignBillingWithPlanChangeDate: Boolean?,
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
+        @ExcludeMissing
+        private val alignBillingWithPlanChangeDate: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
         @JsonProperty("billing_cycle_alignment")
-        private val billingCycleAlignment: BillingCycleAlignment?,
+        @ExcludeMissing
+        private val billingCycleAlignment: JsonField<BillingCycleAlignment> = JsonMissing.of(),
         @JsonProperty("billing_cycle_anchor_configuration")
-        private val billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?,
-        @JsonProperty("change_date") private val changeDate: OffsetDateTime?,
-        @JsonProperty("coupon_redemption_code") private val couponRedemptionCode: String?,
-        @JsonProperty("credits_overage_rate") private val creditsOverageRate: Double?,
-        @JsonProperty("default_invoice_memo") private val defaultInvoiceMemo: String?,
-        @JsonProperty("external_plan_id") private val externalPlanId: String?,
-        @JsonProperty("filter") private val filter: String?,
-        @JsonProperty("initial_phase_order") private val initialPhaseOrder: Long?,
-        @JsonProperty("invoicing_threshold") private val invoicingThreshold: String?,
-        @JsonProperty("net_terms") private val netTerms: Long?,
-        @JsonProperty("per_credit_overage_amount") private val perCreditOverageAmount: Double?,
-        @JsonProperty("plan_id") private val planId: String?,
-        @JsonProperty("plan_version_number") private val planVersionNumber: Long?,
-        @JsonProperty("price_overrides") private val priceOverrides: List<JsonValue>?,
-        @JsonProperty("remove_adjustments") private val removeAdjustments: List<RemoveAdjustment>?,
-        @JsonProperty("remove_prices") private val removePrices: List<RemovePrice>?,
+        @ExcludeMissing
+        private val billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
+            JsonMissing.of(),
+        @JsonProperty("change_date")
+        @ExcludeMissing
+        private val changeDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("coupon_redemption_code")
+        @ExcludeMissing
+        private val couponRedemptionCode: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("credits_overage_rate")
+        @ExcludeMissing
+        private val creditsOverageRate: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("default_invoice_memo")
+        @ExcludeMissing
+        private val defaultInvoiceMemo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("external_plan_id")
+        @ExcludeMissing
+        private val externalPlanId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("filter")
+        @ExcludeMissing
+        private val filter: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("initial_phase_order")
+        @ExcludeMissing
+        private val initialPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("invoicing_threshold")
+        @ExcludeMissing
+        private val invoicingThreshold: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("per_credit_overage_amount")
+        @ExcludeMissing
+        private val perCreditOverageAmount: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("plan_id")
+        @ExcludeMissing
+        private val planId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("plan_version_number")
+        @ExcludeMissing
+        private val planVersionNumber: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("price_overrides")
+        @ExcludeMissing
+        private val priceOverrides: JsonField<List<JsonValue>> = JsonMissing.of(),
+        @JsonProperty("remove_adjustments")
+        @ExcludeMissing
+        private val removeAdjustments: JsonField<List<RemoveAdjustment>> = JsonMissing.of(),
+        @JsonProperty("remove_prices")
+        @ExcludeMissing
+        private val removePrices: JsonField<List<RemovePrice>> = JsonMissing.of(),
         @JsonProperty("replace_adjustments")
-        private val replaceAdjustments: List<ReplaceAdjustment>?,
-        @JsonProperty("replace_prices") private val replacePrices: List<ReplacePrice>?,
-        @JsonProperty("trial_duration_days") private val trialDurationDays: Long?,
+        @ExcludeMissing
+        private val replaceAdjustments: JsonField<List<ReplaceAdjustment>> = JsonMissing.of(),
+        @JsonProperty("replace_prices")
+        @ExcludeMissing
+        private val replacePrices: JsonField<List<ReplacePrice>> = JsonMissing.of(),
+        @JsonProperty("trial_duration_days")
+        @ExcludeMissing
+        private val trialDurationDays: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
-        @JsonProperty("change_option") fun changeOption(): ChangeOption = changeOption
+        fun changeOption(): ChangeOption = changeOption.getRequired("change_option")
+
+        /**
+         * Additional adjustments to be added to the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun addAdjustments(): Optional<List<AddAdjustment>> =
+            Optional.ofNullable(addAdjustments.getNullable("add_adjustments"))
+
+        /**
+         * Additional prices to be added to the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun addPrices(): Optional<List<AddPrice>> =
+            Optional.ofNullable(addPrices.getNullable("add_prices"))
+
+        /**
+         * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
+         * with the plan change's effective date.
+         */
+        fun alignBillingWithPlanChangeDate(): Optional<Boolean> =
+            Optional.ofNullable(
+                alignBillingWithPlanChangeDate.getNullable("align_billing_with_plan_change_date")
+            )
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. If not specified, this defaults to the
+         * behavior configured for this customer.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        /**
+         * Reset billing periods to be aligned with the plan change's effective date or start of the
+         * month. Defaults to `unchanged` which keeps subscription's existing billing cycle
+         * alignment.
+         */
+        fun billingCycleAlignment(): Optional<BillingCycleAlignment> =
+            Optional.ofNullable(billingCycleAlignment.getNullable("billing_cycle_alignment"))
+
+        fun billingCycleAnchorConfiguration(): Optional<BillingCycleAnchorConfiguration> =
+            Optional.ofNullable(
+                billingCycleAnchorConfiguration.getNullable("billing_cycle_anchor_configuration")
+            )
+
+        /**
+         * The date that the plan change should take effect. This parameter can only be passed if
+         * the `change_option` is `requested_date`.
+         */
+        fun changeDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(changeDate.getNullable("change_date"))
+
+        /**
+         * Redemption code to be used for this subscription. If the coupon cannot be found by its
+         * redemption code, or cannot be redeemed, an error response will be returned and the
+         * subscription creation or plan change will not be scheduled.
+         */
+        fun couponRedemptionCode(): Optional<String> =
+            Optional.ofNullable(couponRedemptionCode.getNullable("coupon_redemption_code"))
+
+        fun creditsOverageRate(): Optional<Double> =
+            Optional.ofNullable(creditsOverageRate.getNullable("credits_overage_rate"))
+
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(): Optional<String> =
+            Optional.ofNullable(defaultInvoiceMemo.getNullable("default_invoice_memo"))
+
+        /**
+         * The external_plan_id of the plan that the given subscription should be switched to. Note
+         * that either this property or `plan_id` must be specified.
+         */
+        fun externalPlanId(): Optional<String> =
+            Optional.ofNullable(externalPlanId.getNullable("external_plan_id"))
+
+        /**
+         * An additional filter to apply to usage queries. This filter must be expressed as a
+         * boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+         * null, usage queries will not include any additional filter.
+         */
+        fun filter(): Optional<String> = Optional.ofNullable(filter.getNullable("filter"))
+
+        /** The phase of the plan to start with */
+        fun initialPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(initialPhaseOrder.getNullable("initial_phase_order"))
+
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(): Optional<String> =
+            Optional.ofNullable(invoicingThreshold.getNullable("invoicing_threshold"))
+
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+         * provided, this defaults to the value specified in the plan.
+         */
+        fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms.getNullable("net_terms"))
+
+        fun perCreditOverageAmount(): Optional<Double> =
+            Optional.ofNullable(perCreditOverageAmount.getNullable("per_credit_overage_amount"))
+
+        /**
+         * The plan that the given subscription should be switched to. Note that either this
+         * property or `external_plan_id` must be specified.
+         */
+        fun planId(): Optional<String> = Optional.ofNullable(planId.getNullable("plan_id"))
+
+        /**
+         * Specifies which version of the plan to change to. If null, the default version will be
+         * used.
+         */
+        fun planVersionNumber(): Optional<Long> =
+            Optional.ofNullable(planVersionNumber.getNullable("plan_version_number"))
+
+        /** Optionally provide a list of overrides for prices on the plan */
+        fun priceOverrides(): Optional<List<JsonValue>> =
+            Optional.ofNullable(priceOverrides.getNullable("price_overrides"))
+
+        /**
+         * Plan adjustments to be removed from the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun removeAdjustments(): Optional<List<RemoveAdjustment>> =
+            Optional.ofNullable(removeAdjustments.getNullable("remove_adjustments"))
+
+        /**
+         * Plan prices to be removed from the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun removePrices(): Optional<List<RemovePrice>> =
+            Optional.ofNullable(removePrices.getNullable("remove_prices"))
+
+        /**
+         * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+         * available for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replaceAdjustments(): Optional<List<ReplaceAdjustment>> =
+            Optional.ofNullable(replaceAdjustments.getNullable("replace_adjustments"))
+
+        /**
+         * Plan prices to be replaced with additional prices on the subscription. (Only available
+         * for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replacePrices(): Optional<List<ReplacePrice>> =
+            Optional.ofNullable(replacePrices.getNullable("replace_prices"))
+
+        /**
+         * The duration of the trial period in days. If not provided, this defaults to the value
+         * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+         */
+        fun trialDurationDays(): Optional<Long> =
+            Optional.ofNullable(trialDurationDays.getNullable("trial_duration_days"))
+
+        @JsonProperty("change_option")
+        @ExcludeMissing
+        fun _changeOption(): JsonField<ChangeOption> = changeOption
 
         /**
          * Additional adjustments to be added to the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
          */
         @JsonProperty("add_adjustments")
-        fun addAdjustments(): Optional<List<AddAdjustment>> = Optional.ofNullable(addAdjustments)
+        @ExcludeMissing
+        fun _addAdjustments(): JsonField<List<AddAdjustment>> = addAdjustments
 
         /**
          * Additional prices to be added to the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
          */
         @JsonProperty("add_prices")
-        fun addPrices(): Optional<List<AddPrice>> = Optional.ofNullable(addPrices)
+        @ExcludeMissing
+        fun _addPrices(): JsonField<List<AddPrice>> = addPrices
 
         /**
          * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
          * with the plan change's effective date.
          */
         @JsonProperty("align_billing_with_plan_change_date")
-        fun alignBillingWithPlanChangeDate(): Optional<Boolean> =
-            Optional.ofNullable(alignBillingWithPlanChangeDate)
+        @ExcludeMissing
+        fun _alignBillingWithPlanChangeDate(): JsonField<Boolean> = alignBillingWithPlanChangeDate
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -260,7 +764,8 @@ constructor(
          * behavior configured for this customer.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * Reset billing periods to be aligned with the plan change's effective date or start of the
@@ -268,19 +773,21 @@ constructor(
          * alignment.
          */
         @JsonProperty("billing_cycle_alignment")
-        fun billingCycleAlignment(): Optional<BillingCycleAlignment> =
-            Optional.ofNullable(billingCycleAlignment)
+        @ExcludeMissing
+        fun _billingCycleAlignment(): JsonField<BillingCycleAlignment> = billingCycleAlignment
 
         @JsonProperty("billing_cycle_anchor_configuration")
-        fun billingCycleAnchorConfiguration(): Optional<BillingCycleAnchorConfiguration> =
-            Optional.ofNullable(billingCycleAnchorConfiguration)
+        @ExcludeMissing
+        fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+            billingCycleAnchorConfiguration
 
         /**
          * The date that the plan change should take effect. This parameter can only be passed if
          * the `change_option` is `requested_date`.
          */
         @JsonProperty("change_date")
-        fun changeDate(): Optional<OffsetDateTime> = Optional.ofNullable(changeDate)
+        @ExcludeMissing
+        fun _changeDate(): JsonField<OffsetDateTime> = changeDate
 
         /**
          * Redemption code to be used for this subscription. If the coupon cannot be found by its
@@ -288,24 +795,28 @@ constructor(
          * subscription creation or plan change will not be scheduled.
          */
         @JsonProperty("coupon_redemption_code")
-        fun couponRedemptionCode(): Optional<String> = Optional.ofNullable(couponRedemptionCode)
+        @ExcludeMissing
+        fun _couponRedemptionCode(): JsonField<String> = couponRedemptionCode
 
         @JsonProperty("credits_overage_rate")
-        fun creditsOverageRate(): Optional<Double> = Optional.ofNullable(creditsOverageRate)
+        @ExcludeMissing
+        fun _creditsOverageRate(): JsonField<Double> = creditsOverageRate
 
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
         @JsonProperty("default_invoice_memo")
-        fun defaultInvoiceMemo(): Optional<String> = Optional.ofNullable(defaultInvoiceMemo)
+        @ExcludeMissing
+        fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
         /**
          * The external_plan_id of the plan that the given subscription should be switched to. Note
          * that either this property or `plan_id` must be specified.
          */
         @JsonProperty("external_plan_id")
-        fun externalPlanId(): Optional<String> = Optional.ofNullable(externalPlanId)
+        @ExcludeMissing
+        fun _externalPlanId(): JsonField<String> = externalPlanId
 
         /**
          * An additional filter to apply to usage queries. This filter must be expressed as a
@@ -313,11 +824,12 @@ constructor(
          * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
          * null, usage queries will not include any additional filter.
          */
-        @JsonProperty("filter") fun filter(): Optional<String> = Optional.ofNullable(filter)
+        @JsonProperty("filter") @ExcludeMissing fun _filter(): JsonField<String> = filter
 
         /** The phase of the plan to start with */
         @JsonProperty("initial_phase_order")
-        fun initialPhaseOrder(): Optional<Long> = Optional.ofNullable(initialPhaseOrder)
+        @ExcludeMissing
+        fun _initialPhaseOrder(): JsonField<Long> = initialPhaseOrder
 
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
@@ -325,76 +837,116 @@ constructor(
          * billing period.
          */
         @JsonProperty("invoicing_threshold")
-        fun invoicingThreshold(): Optional<String> = Optional.ofNullable(invoicingThreshold)
+        @ExcludeMissing
+        fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
          * provided, this defaults to the value specified in the plan.
          */
-        @JsonProperty("net_terms") fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms)
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         @JsonProperty("per_credit_overage_amount")
-        fun perCreditOverageAmount(): Optional<Double> = Optional.ofNullable(perCreditOverageAmount)
+        @ExcludeMissing
+        fun _perCreditOverageAmount(): JsonField<Double> = perCreditOverageAmount
 
         /**
          * The plan that the given subscription should be switched to. Note that either this
          * property or `external_plan_id` must be specified.
          */
-        @JsonProperty("plan_id") fun planId(): Optional<String> = Optional.ofNullable(planId)
+        @JsonProperty("plan_id") @ExcludeMissing fun _planId(): JsonField<String> = planId
 
         /**
          * Specifies which version of the plan to change to. If null, the default version will be
          * used.
          */
         @JsonProperty("plan_version_number")
-        fun planVersionNumber(): Optional<Long> = Optional.ofNullable(planVersionNumber)
+        @ExcludeMissing
+        fun _planVersionNumber(): JsonField<Long> = planVersionNumber
 
         /** Optionally provide a list of overrides for prices on the plan */
         @JsonProperty("price_overrides")
-        fun priceOverrides(): Optional<List<JsonValue>> = Optional.ofNullable(priceOverrides)
+        @ExcludeMissing
+        fun _priceOverrides(): JsonField<List<JsonValue>> = priceOverrides
 
         /**
          * Plan adjustments to be removed from the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
          */
         @JsonProperty("remove_adjustments")
-        fun removeAdjustments(): Optional<List<RemoveAdjustment>> =
-            Optional.ofNullable(removeAdjustments)
+        @ExcludeMissing
+        fun _removeAdjustments(): JsonField<List<RemoveAdjustment>> = removeAdjustments
 
         /**
          * Plan prices to be removed from the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
          */
         @JsonProperty("remove_prices")
-        fun removePrices(): Optional<List<RemovePrice>> = Optional.ofNullable(removePrices)
+        @ExcludeMissing
+        fun _removePrices(): JsonField<List<RemovePrice>> = removePrices
 
         /**
          * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
          * available for accounts that have migrated off of legacy subscription overrides)
          */
         @JsonProperty("replace_adjustments")
-        fun replaceAdjustments(): Optional<List<ReplaceAdjustment>> =
-            Optional.ofNullable(replaceAdjustments)
+        @ExcludeMissing
+        fun _replaceAdjustments(): JsonField<List<ReplaceAdjustment>> = replaceAdjustments
 
         /**
          * Plan prices to be replaced with additional prices on the subscription. (Only available
          * for accounts that have migrated off of legacy subscription overrides)
          */
         @JsonProperty("replace_prices")
-        fun replacePrices(): Optional<List<ReplacePrice>> = Optional.ofNullable(replacePrices)
+        @ExcludeMissing
+        fun _replacePrices(): JsonField<List<ReplacePrice>> = replacePrices
 
         /**
          * The duration of the trial period in days. If not provided, this defaults to the value
          * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
          */
         @JsonProperty("trial_duration_days")
-        fun trialDurationDays(): Optional<Long> = Optional.ofNullable(trialDurationDays)
+        @ExcludeMissing
+        fun _trialDurationDays(): JsonField<Long> = trialDurationDays
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionSchedulePlanChangeBody = apply {
+            if (!validated) {
+                changeOption()
+                addAdjustments().map { it.forEach { it.validate() } }
+                addPrices().map { it.forEach { it.validate() } }
+                alignBillingWithPlanChangeDate()
+                autoCollection()
+                billingCycleAlignment()
+                billingCycleAnchorConfiguration().map { it.validate() }
+                changeDate()
+                couponRedemptionCode()
+                creditsOverageRate()
+                defaultInvoiceMemo()
+                externalPlanId()
+                filter()
+                initialPhaseOrder()
+                invoicingThreshold()
+                netTerms()
+                perCreditOverageAmount()
+                planId()
+                planVersionNumber()
+                priceOverrides()
+                removeAdjustments().map { it.forEach { it.validate() } }
+                removePrices().map { it.forEach { it.validate() } }
+                replaceAdjustments().map { it.forEach { it.validate() } }
+                replacePrices().map { it.forEach { it.validate() } }
+                trialDurationDays()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -404,31 +956,33 @@ constructor(
 
         class Builder {
 
-            private var changeOption: ChangeOption? = null
-            private var addAdjustments: MutableList<AddAdjustment>? = null
-            private var addPrices: MutableList<AddPrice>? = null
-            private var alignBillingWithPlanChangeDate: Boolean? = null
-            private var autoCollection: Boolean? = null
-            private var billingCycleAlignment: BillingCycleAlignment? = null
-            private var billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration? = null
-            private var changeDate: OffsetDateTime? = null
-            private var couponRedemptionCode: String? = null
-            private var creditsOverageRate: Double? = null
-            private var defaultInvoiceMemo: String? = null
-            private var externalPlanId: String? = null
-            private var filter: String? = null
-            private var initialPhaseOrder: Long? = null
-            private var invoicingThreshold: String? = null
-            private var netTerms: Long? = null
-            private var perCreditOverageAmount: Double? = null
-            private var planId: String? = null
-            private var planVersionNumber: Long? = null
-            private var priceOverrides: MutableList<JsonValue>? = null
-            private var removeAdjustments: MutableList<RemoveAdjustment>? = null
-            private var removePrices: MutableList<RemovePrice>? = null
-            private var replaceAdjustments: MutableList<ReplaceAdjustment>? = null
-            private var replacePrices: MutableList<ReplacePrice>? = null
-            private var trialDurationDays: Long? = null
+            private var changeOption: JsonField<ChangeOption>? = null
+            private var addAdjustments: JsonField<MutableList<AddAdjustment>>? = null
+            private var addPrices: JsonField<MutableList<AddPrice>>? = null
+            private var alignBillingWithPlanChangeDate: JsonField<Boolean> = JsonMissing.of()
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var billingCycleAlignment: JsonField<BillingCycleAlignment> = JsonMissing.of()
+            private var billingCycleAnchorConfiguration:
+                JsonField<BillingCycleAnchorConfiguration> =
+                JsonMissing.of()
+            private var changeDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponRedemptionCode: JsonField<String> = JsonMissing.of()
+            private var creditsOverageRate: JsonField<Double> = JsonMissing.of()
+            private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
+            private var externalPlanId: JsonField<String> = JsonMissing.of()
+            private var filter: JsonField<String> = JsonMissing.of()
+            private var initialPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var invoicingThreshold: JsonField<String> = JsonMissing.of()
+            private var netTerms: JsonField<Long> = JsonMissing.of()
+            private var perCreditOverageAmount: JsonField<Double> = JsonMissing.of()
+            private var planId: JsonField<String> = JsonMissing.of()
+            private var planVersionNumber: JsonField<Long> = JsonMissing.of()
+            private var priceOverrides: JsonField<MutableList<JsonValue>>? = null
+            private var removeAdjustments: JsonField<MutableList<RemoveAdjustment>>? = null
+            private var removePrices: JsonField<MutableList<RemovePrice>>? = null
+            private var replaceAdjustments: JsonField<MutableList<ReplaceAdjustment>>? = null
+            private var replacePrices: JsonField<MutableList<ReplacePrice>>? = null
+            private var trialDurationDays: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -436,8 +990,9 @@ constructor(
                 subscriptionSchedulePlanChangeBody: SubscriptionSchedulePlanChangeBody
             ) = apply {
                 changeOption = subscriptionSchedulePlanChangeBody.changeOption
-                addAdjustments = subscriptionSchedulePlanChangeBody.addAdjustments?.toMutableList()
-                addPrices = subscriptionSchedulePlanChangeBody.addPrices?.toMutableList()
+                addAdjustments =
+                    subscriptionSchedulePlanChangeBody.addAdjustments.map { it.toMutableList() }
+                addPrices = subscriptionSchedulePlanChangeBody.addPrices.map { it.toMutableList() }
                 alignBillingWithPlanChangeDate =
                     subscriptionSchedulePlanChangeBody.alignBillingWithPlanChangeDate
                 autoCollection = subscriptionSchedulePlanChangeBody.autoCollection
@@ -456,19 +1011,24 @@ constructor(
                 perCreditOverageAmount = subscriptionSchedulePlanChangeBody.perCreditOverageAmount
                 planId = subscriptionSchedulePlanChangeBody.planId
                 planVersionNumber = subscriptionSchedulePlanChangeBody.planVersionNumber
-                priceOverrides = subscriptionSchedulePlanChangeBody.priceOverrides?.toMutableList()
+                priceOverrides =
+                    subscriptionSchedulePlanChangeBody.priceOverrides.map { it.toMutableList() }
                 removeAdjustments =
-                    subscriptionSchedulePlanChangeBody.removeAdjustments?.toMutableList()
-                removePrices = subscriptionSchedulePlanChangeBody.removePrices?.toMutableList()
+                    subscriptionSchedulePlanChangeBody.removeAdjustments.map { it.toMutableList() }
+                removePrices =
+                    subscriptionSchedulePlanChangeBody.removePrices.map { it.toMutableList() }
                 replaceAdjustments =
-                    subscriptionSchedulePlanChangeBody.replaceAdjustments?.toMutableList()
-                replacePrices = subscriptionSchedulePlanChangeBody.replacePrices?.toMutableList()
+                    subscriptionSchedulePlanChangeBody.replaceAdjustments.map { it.toMutableList() }
+                replacePrices =
+                    subscriptionSchedulePlanChangeBody.replacePrices.map { it.toMutableList() }
                 trialDurationDays = subscriptionSchedulePlanChangeBody.trialDurationDays
                 additionalProperties =
                     subscriptionSchedulePlanChangeBody.additionalProperties.toMutableMap()
             }
 
-            fun changeOption(changeOption: ChangeOption) = apply {
+            fun changeOption(changeOption: ChangeOption) = changeOption(JsonField.of(changeOption))
+
+            fun changeOption(changeOption: JsonField<ChangeOption>) = apply {
                 this.changeOption = changeOption
             }
 
@@ -476,9 +1036,8 @@ constructor(
              * Additional adjustments to be added to the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
-            fun addAdjustments(addAdjustments: List<AddAdjustment>?) = apply {
-                this.addAdjustments = addAdjustments?.toMutableList()
-            }
+            fun addAdjustments(addAdjustments: List<AddAdjustment>?) =
+                addAdjustments(JsonField.ofNullable(addAdjustments))
 
             /**
              * Additional adjustments to be added to the subscription. (Only available for accounts
@@ -487,21 +1046,36 @@ constructor(
             fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
                 addAdjustments(addAdjustments.orElse(null))
 
+            /**
+             * Additional adjustments to be added to the subscription. (Only available for accounts
+             * that have migrated off of legacy subscription overrides)
+             */
+            fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+                this.addAdjustments = addAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Additional adjustments to be added to the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
             fun addAddAdjustment(addAdjustment: AddAdjustment) = apply {
-                addAdjustments = (addAdjustments ?: mutableListOf()).apply { add(addAdjustment) }
+                addAdjustments =
+                    (addAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(addAdjustment)
+                    }
             }
 
             /**
              * Additional prices to be added to the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
-            fun addPrices(addPrices: List<AddPrice>?) = apply {
-                this.addPrices = addPrices?.toMutableList()
-            }
+            fun addPrices(addPrices: List<AddPrice>?) = addPrices(JsonField.ofNullable(addPrices))
 
             /**
              * Additional prices to be added to the subscription. (Only available for accounts that
@@ -509,21 +1083,37 @@ constructor(
              */
             fun addPrices(addPrices: Optional<List<AddPrice>>) = addPrices(addPrices.orElse(null))
 
+            /**
+             * Additional prices to be added to the subscription. (Only available for accounts that
+             * have migrated off of legacy subscription overrides)
+             */
+            fun addPrices(addPrices: JsonField<List<AddPrice>>) = apply {
+                this.addPrices = addPrices.map { it.toMutableList() }
+            }
+
             /**
              * Additional prices to be added to the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
             fun addAddPrice(addPrice: AddPrice) = apply {
-                addPrices = (addPrices ?: mutableListOf()).apply { add(addPrice) }
+                addPrices =
+                    (addPrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(addPrice)
+                    }
             }
 
             /**
              * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
              * with the plan change's effective date.
              */
-            fun alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate: Boolean?) = apply {
-                this.alignBillingWithPlanChangeDate = alignBillingWithPlanChangeDate
-            }
+            fun alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate: Boolean?) =
+                alignBillingWithPlanChangeDate(JsonField.ofNullable(alignBillingWithPlanChangeDate))
 
             /**
              * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
@@ -542,14 +1132,22 @@ constructor(
                     alignBillingWithPlanChangeDate.orElse(null) as Boolean?
                 )
 
+            /**
+             * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
+             * with the plan change's effective date.
+             */
+            fun alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate: JsonField<Boolean>) =
+                apply {
+                    this.alignBillingWithPlanChangeDate = alignBillingWithPlanChangeDate
+                }
+
             /**
              * Determines whether issued invoices for this subscription will automatically be
              * charged with the saved payment method on the due date. If not specified, this
              * defaults to the behavior configured for this customer.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Determines whether issued invoices for this subscription will automatically be
@@ -567,14 +1165,22 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
+            /**
+             * Determines whether issued invoices for this subscription will automatically be
+             * charged with the saved payment method on the due date. If not specified, this
+             * defaults to the behavior configured for this customer.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
+            }
+
             /**
              * Reset billing periods to be aligned with the plan change's effective date or start of
              * the month. Defaults to `unchanged` which keeps subscription's existing billing cycle
              * alignment.
              */
-            fun billingCycleAlignment(billingCycleAlignment: BillingCycleAlignment?) = apply {
-                this.billingCycleAlignment = billingCycleAlignment
-            }
+            fun billingCycleAlignment(billingCycleAlignment: BillingCycleAlignment?) =
+                billingCycleAlignment(JsonField.ofNullable(billingCycleAlignment))
 
             /**
              * Reset billing periods to be aligned with the plan change's effective date or start of
@@ -584,19 +1190,37 @@ constructor(
             fun billingCycleAlignment(billingCycleAlignment: Optional<BillingCycleAlignment>) =
                 billingCycleAlignment(billingCycleAlignment.orElse(null))
 
+            /**
+             * Reset billing periods to be aligned with the plan change's effective date or start of
+             * the month. Defaults to `unchanged` which keeps subscription's existing billing cycle
+             * alignment.
+             */
+            fun billingCycleAlignment(billingCycleAlignment: JsonField<BillingCycleAlignment>) =
+                apply {
+                    this.billingCycleAlignment = billingCycleAlignment
+                }
+
             fun billingCycleAnchorConfiguration(
                 billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?
-            ) = apply { this.billingCycleAnchorConfiguration = billingCycleAnchorConfiguration }
+            ) =
+                billingCycleAnchorConfiguration(
+                    JsonField.ofNullable(billingCycleAnchorConfiguration)
+                )
 
             fun billingCycleAnchorConfiguration(
                 billingCycleAnchorConfiguration: Optional<BillingCycleAnchorConfiguration>
             ) = billingCycleAnchorConfiguration(billingCycleAnchorConfiguration.orElse(null))
 
+            fun billingCycleAnchorConfiguration(
+                billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>
+            ) = apply { this.billingCycleAnchorConfiguration = billingCycleAnchorConfiguration }
+
             /**
              * The date that the plan change should take effect. This parameter can only be passed
              * if the `change_option` is `requested_date`.
              */
-            fun changeDate(changeDate: OffsetDateTime?) = apply { this.changeDate = changeDate }
+            fun changeDate(changeDate: OffsetDateTime?) =
+                changeDate(JsonField.ofNullable(changeDate))
 
             /**
              * The date that the plan change should take effect. This parameter can only be passed
@@ -605,14 +1229,21 @@ constructor(
             fun changeDate(changeDate: Optional<OffsetDateTime>) =
                 changeDate(changeDate.orElse(null))
 
+            /**
+             * The date that the plan change should take effect. This parameter can only be passed
+             * if the `change_option` is `requested_date`.
+             */
+            fun changeDate(changeDate: JsonField<OffsetDateTime>) = apply {
+                this.changeDate = changeDate
+            }
+
             /**
              * Redemption code to be used for this subscription. If the coupon cannot be found by
              * its redemption code, or cannot be redeemed, an error response will be returned and
              * the subscription creation or plan change will not be scheduled.
              */
-            fun couponRedemptionCode(couponRedemptionCode: String?) = apply {
-                this.couponRedemptionCode = couponRedemptionCode
-            }
+            fun couponRedemptionCode(couponRedemptionCode: String?) =
+                couponRedemptionCode(JsonField.ofNullable(couponRedemptionCode))
 
             /**
              * Redemption code to be used for this subscription. If the coupon cannot be found by
@@ -622,10 +1253,18 @@ constructor(
             fun couponRedemptionCode(couponRedemptionCode: Optional<String>) =
                 couponRedemptionCode(couponRedemptionCode.orElse(null))
 
-            fun creditsOverageRate(creditsOverageRate: Double?) = apply {
-                this.creditsOverageRate = creditsOverageRate
+            /**
+             * Redemption code to be used for this subscription. If the coupon cannot be found by
+             * its redemption code, or cannot be redeemed, an error response will be returned and
+             * the subscription creation or plan change will not be scheduled.
+             */
+            fun couponRedemptionCode(couponRedemptionCode: JsonField<String>) = apply {
+                this.couponRedemptionCode = couponRedemptionCode
             }
 
+            fun creditsOverageRate(creditsOverageRate: Double?) =
+                creditsOverageRate(JsonField.ofNullable(creditsOverageRate))
+
             fun creditsOverageRate(creditsOverageRate: Double) =
                 creditsOverageRate(creditsOverageRate as Double?)
 
@@ -633,13 +1272,16 @@ constructor(
             fun creditsOverageRate(creditsOverageRate: Optional<Double>) =
                 creditsOverageRate(creditsOverageRate.orElse(null) as Double?)
 
+            fun creditsOverageRate(creditsOverageRate: JsonField<Double>) = apply {
+                this.creditsOverageRate = creditsOverageRate
+            }
+
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
              * provided, it is determined by the plan configuration.
              */
-            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) = apply {
-                this.defaultInvoiceMemo = defaultInvoiceMemo
-            }
+            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+                defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
 
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
@@ -648,13 +1290,20 @@ constructor(
             fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
                 defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+            /**
+             * Determines the default memo on this subscription's invoices. Note that if this is not
+             * provided, it is determined by the plan configuration.
+             */
+            fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+                this.defaultInvoiceMemo = defaultInvoiceMemo
+            }
+
             /**
              * The external_plan_id of the plan that the given subscription should be switched to.
              * Note that either this property or `plan_id` must be specified.
              */
-            fun externalPlanId(externalPlanId: String?) = apply {
-                this.externalPlanId = externalPlanId
-            }
+            fun externalPlanId(externalPlanId: String?) =
+                externalPlanId(JsonField.ofNullable(externalPlanId))
 
             /**
              * The external_plan_id of the plan that the given subscription should be switched to.
@@ -663,13 +1312,21 @@ constructor(
             fun externalPlanId(externalPlanId: Optional<String>) =
                 externalPlanId(externalPlanId.orElse(null))
 
+            /**
+             * The external_plan_id of the plan that the given subscription should be switched to.
+             * Note that either this property or `plan_id` must be specified.
+             */
+            fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+                this.externalPlanId = externalPlanId
+            }
+
             /**
              * An additional filter to apply to usage queries. This filter must be expressed as a
              * boolean
              * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
              * null, usage queries will not include any additional filter.
              */
-            fun filter(filter: String?) = apply { this.filter = filter }
+            fun filter(filter: String?) = filter(JsonField.ofNullable(filter))
 
             /**
              * An additional filter to apply to usage queries. This filter must be expressed as a
@@ -679,10 +1336,17 @@ constructor(
              */
             fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+            /**
+             * An additional filter to apply to usage queries. This filter must be expressed as a
+             * boolean
+             * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+             * null, usage queries will not include any additional filter.
+             */
+            fun filter(filter: JsonField<String>) = apply { this.filter = filter }
+
             /** The phase of the plan to start with */
-            fun initialPhaseOrder(initialPhaseOrder: Long?) = apply {
-                this.initialPhaseOrder = initialPhaseOrder
-            }
+            fun initialPhaseOrder(initialPhaseOrder: Long?) =
+                initialPhaseOrder(JsonField.ofNullable(initialPhaseOrder))
 
             /** The phase of the plan to start with */
             fun initialPhaseOrder(initialPhaseOrder: Long) =
@@ -693,14 +1357,18 @@ constructor(
             fun initialPhaseOrder(initialPhaseOrder: Optional<Long>) =
                 initialPhaseOrder(initialPhaseOrder.orElse(null) as Long?)
 
+            /** The phase of the plan to start with */
+            fun initialPhaseOrder(initialPhaseOrder: JsonField<Long>) = apply {
+                this.initialPhaseOrder = initialPhaseOrder
+            }
+
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
              * issued for the subscription. If not specified, invoices will only be issued at the
              * end of the billing period.
              */
-            fun invoicingThreshold(invoicingThreshold: String?) = apply {
-                this.invoicingThreshold = invoicingThreshold
-            }
+            fun invoicingThreshold(invoicingThreshold: String?) =
+                invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
 
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
@@ -710,12 +1378,21 @@ constructor(
             fun invoicingThreshold(invoicingThreshold: Optional<String>) =
                 invoicingThreshold(invoicingThreshold.orElse(null))
 
+            /**
+             * When this subscription's accrued usage reaches this threshold, an invoice will be
+             * issued for the subscription. If not specified, invoices will only be issued at the
+             * end of the billing period.
+             */
+            fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+                this.invoicingThreshold = invoicingThreshold
+            }
+
             /**
              * The net terms determines the difference between the invoice date and the issue date
              * for the invoice. If you intend the invoice to be due on issue, set this to 0. If not
              * provided, this defaults to the value specified in the plan.
              */
-            fun netTerms(netTerms: Long?) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long?) = netTerms(JsonField.ofNullable(netTerms))
 
             /**
              * The net terms determines the difference between the invoice date and the issue date
@@ -732,9 +1409,15 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
-            fun perCreditOverageAmount(perCreditOverageAmount: Double?) = apply {
-                this.perCreditOverageAmount = perCreditOverageAmount
-            }
+            /**
+             * The net terms determines the difference between the invoice date and the issue date
+             * for the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+             * provided, this defaults to the value specified in the plan.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
+
+            fun perCreditOverageAmount(perCreditOverageAmount: Double?) =
+                perCreditOverageAmount(JsonField.ofNullable(perCreditOverageAmount))
 
             fun perCreditOverageAmount(perCreditOverageAmount: Double) =
                 perCreditOverageAmount(perCreditOverageAmount as Double?)
@@ -743,11 +1426,15 @@ constructor(
             fun perCreditOverageAmount(perCreditOverageAmount: Optional<Double>) =
                 perCreditOverageAmount(perCreditOverageAmount.orElse(null) as Double?)
 
+            fun perCreditOverageAmount(perCreditOverageAmount: JsonField<Double>) = apply {
+                this.perCreditOverageAmount = perCreditOverageAmount
+            }
+
             /**
              * The plan that the given subscription should be switched to. Note that either this
              * property or `external_plan_id` must be specified.
              */
-            fun planId(planId: String?) = apply { this.planId = planId }
+            fun planId(planId: String?) = planId(JsonField.ofNullable(planId))
 
             /**
              * The plan that the given subscription should be switched to. Note that either this
@@ -755,13 +1442,18 @@ constructor(
              */
             fun planId(planId: Optional<String>) = planId(planId.orElse(null))
 
+            /**
+             * The plan that the given subscription should be switched to. Note that either this
+             * property or `external_plan_id` must be specified.
+             */
+            fun planId(planId: JsonField<String>) = apply { this.planId = planId }
+
             /**
              * Specifies which version of the plan to change to. If null, the default version will
              * be used.
              */
-            fun planVersionNumber(planVersionNumber: Long?) = apply {
-                this.planVersionNumber = planVersionNumber
-            }
+            fun planVersionNumber(planVersionNumber: Long?) =
+                planVersionNumber(JsonField.ofNullable(planVersionNumber))
 
             /**
              * Specifies which version of the plan to change to. If null, the default version will
@@ -778,27 +1470,47 @@ constructor(
             fun planVersionNumber(planVersionNumber: Optional<Long>) =
                 planVersionNumber(planVersionNumber.orElse(null) as Long?)
 
-            /** Optionally provide a list of overrides for prices on the plan */
-            fun priceOverrides(priceOverrides: List<JsonValue>?) = apply {
-                this.priceOverrides = priceOverrides?.toMutableList()
+            /**
+             * Specifies which version of the plan to change to. If null, the default version will
+             * be used.
+             */
+            fun planVersionNumber(planVersionNumber: JsonField<Long>) = apply {
+                this.planVersionNumber = planVersionNumber
             }
 
+            /** Optionally provide a list of overrides for prices on the plan */
+            fun priceOverrides(priceOverrides: List<JsonValue>?) =
+                priceOverrides(JsonField.ofNullable(priceOverrides))
+
             /** Optionally provide a list of overrides for prices on the plan */
             fun priceOverrides(priceOverrides: Optional<List<JsonValue>>) =
                 priceOverrides(priceOverrides.orElse(null))
 
+            /** Optionally provide a list of overrides for prices on the plan */
+            fun priceOverrides(priceOverrides: JsonField<List<JsonValue>>) = apply {
+                this.priceOverrides = priceOverrides.map { it.toMutableList() }
+            }
+
             /** Optionally provide a list of overrides for prices on the plan */
             fun addPriceOverride(priceOverride: JsonValue) = apply {
-                priceOverrides = (priceOverrides ?: mutableListOf()).apply { add(priceOverride) }
+                priceOverrides =
+                    (priceOverrides ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(priceOverride)
+                    }
             }
 
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
-            fun removeAdjustments(removeAdjustments: List<RemoveAdjustment>?) = apply {
-                this.removeAdjustments = removeAdjustments?.toMutableList()
-            }
+            fun removeAdjustments(removeAdjustments: List<RemoveAdjustment>?) =
+                removeAdjustments(JsonField.ofNullable(removeAdjustments))
 
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
@@ -807,22 +1519,37 @@ constructor(
             fun removeAdjustments(removeAdjustments: Optional<List<RemoveAdjustment>>) =
                 removeAdjustments(removeAdjustments.orElse(null))
 
+            /**
+             * Plan adjustments to be removed from the subscription. (Only available for accounts
+             * that have migrated off of legacy subscription overrides)
+             */
+            fun removeAdjustments(removeAdjustments: JsonField<List<RemoveAdjustment>>) = apply {
+                this.removeAdjustments = removeAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Plan adjustments to be removed from the subscription. (Only available for accounts
              * that have migrated off of legacy subscription overrides)
              */
             fun addRemoveAdjustment(removeAdjustment: RemoveAdjustment) = apply {
                 removeAdjustments =
-                    (removeAdjustments ?: mutableListOf()).apply { add(removeAdjustment) }
+                    (removeAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(removeAdjustment)
+                    }
             }
 
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
-            fun removePrices(removePrices: List<RemovePrice>?) = apply {
-                this.removePrices = removePrices?.toMutableList()
-            }
+            fun removePrices(removePrices: List<RemovePrice>?) =
+                removePrices(JsonField.ofNullable(removePrices))
 
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
@@ -831,21 +1558,37 @@ constructor(
             fun removePrices(removePrices: Optional<List<RemovePrice>>) =
                 removePrices(removePrices.orElse(null))
 
+            /**
+             * Plan prices to be removed from the subscription. (Only available for accounts that
+             * have migrated off of legacy subscription overrides)
+             */
+            fun removePrices(removePrices: JsonField<List<RemovePrice>>) = apply {
+                this.removePrices = removePrices.map { it.toMutableList() }
+            }
+
             /**
              * Plan prices to be removed from the subscription. (Only available for accounts that
              * have migrated off of legacy subscription overrides)
              */
             fun addRemovePrice(removePrice: RemovePrice) = apply {
-                removePrices = (removePrices ?: mutableListOf()).apply { add(removePrice) }
+                removePrices =
+                    (removePrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(removePrice)
+                    }
             }
 
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
              * (Only available for accounts that have migrated off of legacy subscription overrides)
              */
-            fun replaceAdjustments(replaceAdjustments: List<ReplaceAdjustment>?) = apply {
-                this.replaceAdjustments = replaceAdjustments?.toMutableList()
-            }
+            fun replaceAdjustments(replaceAdjustments: List<ReplaceAdjustment>?) =
+                replaceAdjustments(JsonField.ofNullable(replaceAdjustments))
 
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
@@ -854,22 +1597,37 @@ constructor(
             fun replaceAdjustments(replaceAdjustments: Optional<List<ReplaceAdjustment>>) =
                 replaceAdjustments(replaceAdjustments.orElse(null))
 
+            /**
+             * Plan adjustments to be replaced with additional adjustments on the subscription.
+             * (Only available for accounts that have migrated off of legacy subscription overrides)
+             */
+            fun replaceAdjustments(replaceAdjustments: JsonField<List<ReplaceAdjustment>>) = apply {
+                this.replaceAdjustments = replaceAdjustments.map { it.toMutableList() }
+            }
+
             /**
              * Plan adjustments to be replaced with additional adjustments on the subscription.
              * (Only available for accounts that have migrated off of legacy subscription overrides)
              */
             fun addReplaceAdjustment(replaceAdjustment: ReplaceAdjustment) = apply {
                 replaceAdjustments =
-                    (replaceAdjustments ?: mutableListOf()).apply { add(replaceAdjustment) }
+                    (replaceAdjustments ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(replaceAdjustment)
+                    }
             }
 
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
              * available for accounts that have migrated off of legacy subscription overrides)
              */
-            fun replacePrices(replacePrices: List<ReplacePrice>?) = apply {
-                this.replacePrices = replacePrices?.toMutableList()
-            }
+            fun replacePrices(replacePrices: List<ReplacePrice>?) =
+                replacePrices(JsonField.ofNullable(replacePrices))
 
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
@@ -878,21 +1636,37 @@ constructor(
             fun replacePrices(replacePrices: Optional<List<ReplacePrice>>) =
                 replacePrices(replacePrices.orElse(null))
 
+            /**
+             * Plan prices to be replaced with additional prices on the subscription. (Only
+             * available for accounts that have migrated off of legacy subscription overrides)
+             */
+            fun replacePrices(replacePrices: JsonField<List<ReplacePrice>>) = apply {
+                this.replacePrices = replacePrices.map { it.toMutableList() }
+            }
+
             /**
              * Plan prices to be replaced with additional prices on the subscription. (Only
              * available for accounts that have migrated off of legacy subscription overrides)
              */
             fun addReplacePrice(replacePrice: ReplacePrice) = apply {
-                replacePrices = (replacePrices ?: mutableListOf()).apply { add(replacePrice) }
+                replacePrices =
+                    (replacePrices ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(replacePrice)
+                    }
             }
 
             /**
              * The duration of the trial period in days. If not provided, this defaults to the value
              * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
              */
-            fun trialDurationDays(trialDurationDays: Long?) = apply {
-                this.trialDurationDays = trialDurationDays
-            }
+            fun trialDurationDays(trialDurationDays: Long?) =
+                trialDurationDays(JsonField.ofNullable(trialDurationDays))
 
             /**
              * The duration of the trial period in days. If not provided, this defaults to the value
@@ -909,6 +1683,14 @@ constructor(
             fun trialDurationDays(trialDurationDays: Optional<Long>) =
                 trialDurationDays(trialDurationDays.orElse(null) as Long?)
 
+            /**
+             * The duration of the trial period in days. If not provided, this defaults to the value
+             * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+             */
+            fun trialDurationDays(trialDurationDays: JsonField<Long>) = apply {
+                this.trialDurationDays = trialDurationDays
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -931,8 +1713,8 @@ constructor(
             fun build(): SubscriptionSchedulePlanChangeBody =
                 SubscriptionSchedulePlanChangeBody(
                     checkNotNull(changeOption) { "`changeOption` is required but was not set" },
-                    addAdjustments?.toImmutable(),
-                    addPrices?.toImmutable(),
+                    (addAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (addPrices ?: JsonMissing.of()).map { it.toImmutable() },
                     alignBillingWithPlanChangeDate,
                     autoCollection,
                     billingCycleAlignment,
@@ -949,11 +1731,11 @@ constructor(
                     perCreditOverageAmount,
                     planId,
                     planVersionNumber,
-                    priceOverrides?.toImmutable(),
-                    removeAdjustments?.toImmutable(),
-                    removePrices?.toImmutable(),
-                    replaceAdjustments?.toImmutable(),
-                    replacePrices?.toImmutable(),
+                    (priceOverrides ?: JsonMissing.of()).map { it.toImmutable() },
+                    (removeAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (removePrices ?: JsonMissing.of()).map { it.toImmutable() },
+                    (replaceAdjustments ?: JsonMissing.of()).map { it.toImmutable() },
+                    (replacePrices ?: JsonMissing.of()).map { it.toImmutable() },
                     trialDurationDays,
                     additionalProperties.toImmutable(),
                 )
@@ -1008,6 +1790,10 @@ constructor(
 
         fun changeOption(changeOption: ChangeOption) = apply { body.changeOption(changeOption) }
 
+        fun changeOption(changeOption: JsonField<ChangeOption>) = apply {
+            body.changeOption(changeOption)
+        }
+
         /**
          * Additional adjustments to be added to the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
@@ -1023,6 +1809,14 @@ constructor(
         fun addAdjustments(addAdjustments: Optional<List<AddAdjustment>>) =
             addAdjustments(addAdjustments.orElse(null))
 
+        /**
+         * Additional adjustments to be added to the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun addAdjustments(addAdjustments: JsonField<List<AddAdjustment>>) = apply {
+            body.addAdjustments(addAdjustments)
+        }
+
         /**
          * Additional adjustments to be added to the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
@@ -1043,6 +1837,12 @@ constructor(
          */
         fun addPrices(addPrices: Optional<List<AddPrice>>) = addPrices(addPrices.orElse(null))
 
+        /**
+         * Additional prices to be added to the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun addPrices(addPrices: JsonField<List<AddPrice>>) = apply { body.addPrices(addPrices) }
+
         /**
          * Additional prices to be added to the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
@@ -1072,6 +1872,15 @@ constructor(
         fun alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate: Optional<Boolean>) =
             alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate.orElse(null) as Boolean?)
 
+        /**
+         * [DEPRECATED] Use billing_cycle_alignment instead. Reset billing periods to be aligned
+         * with the plan change's effective date.
+         */
+        fun alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate: JsonField<Boolean>) =
+            apply {
+                body.alignBillingWithPlanChangeDate(alignBillingWithPlanChangeDate)
+            }
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. If not specified, this defaults to the
@@ -1095,6 +1904,15 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. If not specified, this defaults to the
+         * behavior configured for this customer.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         /**
          * Reset billing periods to be aligned with the plan change's effective date or start of the
          * month. Defaults to `unchanged` which keeps subscription's existing billing cycle
@@ -1112,6 +1930,15 @@ constructor(
         fun billingCycleAlignment(billingCycleAlignment: Optional<BillingCycleAlignment>) =
             billingCycleAlignment(billingCycleAlignment.orElse(null))
 
+        /**
+         * Reset billing periods to be aligned with the plan change's effective date or start of the
+         * month. Defaults to `unchanged` which keeps subscription's existing billing cycle
+         * alignment.
+         */
+        fun billingCycleAlignment(billingCycleAlignment: JsonField<BillingCycleAlignment>) = apply {
+            body.billingCycleAlignment(billingCycleAlignment)
+        }
+
         fun billingCycleAnchorConfiguration(
             billingCycleAnchorConfiguration: BillingCycleAnchorConfiguration?
         ) = apply { body.billingCycleAnchorConfiguration(billingCycleAnchorConfiguration) }
@@ -1120,6 +1947,10 @@ constructor(
             billingCycleAnchorConfiguration: Optional<BillingCycleAnchorConfiguration>
         ) = billingCycleAnchorConfiguration(billingCycleAnchorConfiguration.orElse(null))
 
+        fun billingCycleAnchorConfiguration(
+            billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>
+        ) = apply { body.billingCycleAnchorConfiguration(billingCycleAnchorConfiguration) }
+
         /**
          * The date that the plan change should take effect. This parameter can only be passed if
          * the `change_option` is `requested_date`.
@@ -1132,6 +1963,14 @@ constructor(
          */
         fun changeDate(changeDate: Optional<OffsetDateTime>) = changeDate(changeDate.orElse(null))
 
+        /**
+         * The date that the plan change should take effect. This parameter can only be passed if
+         * the `change_option` is `requested_date`.
+         */
+        fun changeDate(changeDate: JsonField<OffsetDateTime>) = apply {
+            body.changeDate(changeDate)
+        }
+
         /**
          * Redemption code to be used for this subscription. If the coupon cannot be found by its
          * redemption code, or cannot be redeemed, an error response will be returned and the
@@ -1149,6 +1988,15 @@ constructor(
         fun couponRedemptionCode(couponRedemptionCode: Optional<String>) =
             couponRedemptionCode(couponRedemptionCode.orElse(null))
 
+        /**
+         * Redemption code to be used for this subscription. If the coupon cannot be found by its
+         * redemption code, or cannot be redeemed, an error response will be returned and the
+         * subscription creation or plan change will not be scheduled.
+         */
+        fun couponRedemptionCode(couponRedemptionCode: JsonField<String>) = apply {
+            body.couponRedemptionCode(couponRedemptionCode)
+        }
+
         fun creditsOverageRate(creditsOverageRate: Double?) = apply {
             body.creditsOverageRate(creditsOverageRate)
         }
@@ -1160,6 +2008,10 @@ constructor(
         fun creditsOverageRate(creditsOverageRate: Optional<Double>) =
             creditsOverageRate(creditsOverageRate.orElse(null) as Double?)
 
+        fun creditsOverageRate(creditsOverageRate: JsonField<Double>) = apply {
+            body.creditsOverageRate(creditsOverageRate)
+        }
+
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
@@ -1175,6 +2027,14 @@ constructor(
         fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
             defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+            body.defaultInvoiceMemo(defaultInvoiceMemo)
+        }
+
         /**
          * The external_plan_id of the plan that the given subscription should be switched to. Note
          * that either this property or `plan_id` must be specified.
@@ -1188,6 +2048,14 @@ constructor(
         fun externalPlanId(externalPlanId: Optional<String>) =
             externalPlanId(externalPlanId.orElse(null))
 
+        /**
+         * The external_plan_id of the plan that the given subscription should be switched to. Note
+         * that either this property or `plan_id` must be specified.
+         */
+        fun externalPlanId(externalPlanId: JsonField<String>) = apply {
+            body.externalPlanId(externalPlanId)
+        }
+
         /**
          * An additional filter to apply to usage queries. This filter must be expressed as a
          * boolean
@@ -1204,6 +2072,14 @@ constructor(
          */
         fun filter(filter: Optional<String>) = filter(filter.orElse(null))
 
+        /**
+         * An additional filter to apply to usage queries. This filter must be expressed as a
+         * boolean
+         * [computed property](../guides/extensibility/advanced-metrics#computed-properties). If
+         * null, usage queries will not include any additional filter.
+         */
+        fun filter(filter: JsonField<String>) = apply { body.filter(filter) }
+
         /** The phase of the plan to start with */
         fun initialPhaseOrder(initialPhaseOrder: Long?) = apply {
             body.initialPhaseOrder(initialPhaseOrder)
@@ -1218,6 +2094,11 @@ constructor(
         fun initialPhaseOrder(initialPhaseOrder: Optional<Long>) =
             initialPhaseOrder(initialPhaseOrder.orElse(null) as Long?)
 
+        /** The phase of the plan to start with */
+        fun initialPhaseOrder(initialPhaseOrder: JsonField<Long>) = apply {
+            body.initialPhaseOrder(initialPhaseOrder)
+        }
+
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
          * for the subscription. If not specified, invoices will only be issued at the end of the
@@ -1235,6 +2116,15 @@ constructor(
         fun invoicingThreshold(invoicingThreshold: Optional<String>) =
             invoicingThreshold(invoicingThreshold.orElse(null))
 
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+            body.invoicingThreshold(invoicingThreshold)
+        }
+
         /**
          * The net terms determines the difference between the invoice date and the issue date for
          * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
@@ -1257,6 +2147,13 @@ constructor(
         @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
         fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+        /**
+         * The net terms determines the difference between the invoice date and the issue date for
+         * the invoice. If you intend the invoice to be due on issue, set this to 0. If not
+         * provided, this defaults to the value specified in the plan.
+         */
+        fun netTerms(netTerms: JsonField<Long>) = apply { body.netTerms(netTerms) }
+
         fun perCreditOverageAmount(perCreditOverageAmount: Double?) = apply {
             body.perCreditOverageAmount(perCreditOverageAmount)
         }
@@ -1268,6 +2165,10 @@ constructor(
         fun perCreditOverageAmount(perCreditOverageAmount: Optional<Double>) =
             perCreditOverageAmount(perCreditOverageAmount.orElse(null) as Double?)
 
+        fun perCreditOverageAmount(perCreditOverageAmount: JsonField<Double>) = apply {
+            body.perCreditOverageAmount(perCreditOverageAmount)
+        }
+
         /**
          * The plan that the given subscription should be switched to. Note that either this
          * property or `external_plan_id` must be specified.
@@ -1280,6 +2181,12 @@ constructor(
          */
         fun planId(planId: Optional<String>) = planId(planId.orElse(null))
 
+        /**
+         * The plan that the given subscription should be switched to. Note that either this
+         * property or `external_plan_id` must be specified.
+         */
+        fun planId(planId: JsonField<String>) = apply { body.planId(planId) }
+
         /**
          * Specifies which version of the plan to change to. If null, the default version will be
          * used.
@@ -1303,6 +2210,14 @@ constructor(
         fun planVersionNumber(planVersionNumber: Optional<Long>) =
             planVersionNumber(planVersionNumber.orElse(null) as Long?)
 
+        /**
+         * Specifies which version of the plan to change to. If null, the default version will be
+         * used.
+         */
+        fun planVersionNumber(planVersionNumber: JsonField<Long>) = apply {
+            body.planVersionNumber(planVersionNumber)
+        }
+
         /** Optionally provide a list of overrides for prices on the plan */
         fun priceOverrides(priceOverrides: List<JsonValue>?) = apply {
             body.priceOverrides(priceOverrides)
@@ -1312,6 +2227,11 @@ constructor(
         fun priceOverrides(priceOverrides: Optional<List<JsonValue>>) =
             priceOverrides(priceOverrides.orElse(null))
 
+        /** Optionally provide a list of overrides for prices on the plan */
+        fun priceOverrides(priceOverrides: JsonField<List<JsonValue>>) = apply {
+            body.priceOverrides(priceOverrides)
+        }
+
         /** Optionally provide a list of overrides for prices on the plan */
         fun addPriceOverride(priceOverride: JsonValue) = apply {
             body.addPriceOverride(priceOverride)
@@ -1332,6 +2252,14 @@ constructor(
         fun removeAdjustments(removeAdjustments: Optional<List<RemoveAdjustment>>) =
             removeAdjustments(removeAdjustments.orElse(null))
 
+        /**
+         * Plan adjustments to be removed from the subscription. (Only available for accounts that
+         * have migrated off of legacy subscription overrides)
+         */
+        fun removeAdjustments(removeAdjustments: JsonField<List<RemoveAdjustment>>) = apply {
+            body.removeAdjustments(removeAdjustments)
+        }
+
         /**
          * Plan adjustments to be removed from the subscription. (Only available for accounts that
          * have migrated off of legacy subscription overrides)
@@ -1355,6 +2283,14 @@ constructor(
         fun removePrices(removePrices: Optional<List<RemovePrice>>) =
             removePrices(removePrices.orElse(null))
 
+        /**
+         * Plan prices to be removed from the subscription. (Only available for accounts that have
+         * migrated off of legacy subscription overrides)
+         */
+        fun removePrices(removePrices: JsonField<List<RemovePrice>>) = apply {
+            body.removePrices(removePrices)
+        }
+
         /**
          * Plan prices to be removed from the subscription. (Only available for accounts that have
          * migrated off of legacy subscription overrides)
@@ -1376,6 +2312,14 @@ constructor(
         fun replaceAdjustments(replaceAdjustments: Optional<List<ReplaceAdjustment>>) =
             replaceAdjustments(replaceAdjustments.orElse(null))
 
+        /**
+         * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
+         * available for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replaceAdjustments(replaceAdjustments: JsonField<List<ReplaceAdjustment>>) = apply {
+            body.replaceAdjustments(replaceAdjustments)
+        }
+
         /**
          * Plan adjustments to be replaced with additional adjustments on the subscription. (Only
          * available for accounts that have migrated off of legacy subscription overrides)
@@ -1399,6 +2343,14 @@ constructor(
         fun replacePrices(replacePrices: Optional<List<ReplacePrice>>) =
             replacePrices(replacePrices.orElse(null))
 
+        /**
+         * Plan prices to be replaced with additional prices on the subscription. (Only available
+         * for accounts that have migrated off of legacy subscription overrides)
+         */
+        fun replacePrices(replacePrices: JsonField<List<ReplacePrice>>) = apply {
+            body.replacePrices(replacePrices)
+        }
+
         /**
          * Plan prices to be replaced with additional prices on the subscription. (Only available
          * for accounts that have migrated off of legacy subscription overrides)
@@ -1430,6 +2382,33 @@ constructor(
         fun trialDurationDays(trialDurationDays: Optional<Long>) =
             trialDurationDays(trialDurationDays.orElse(null) as Long?)
 
+        /**
+         * The duration of the trial period in days. If not provided, this defaults to the value
+         * specified in the plan. If `0` is provided, the trial on the plan will be skipped.
+         */
+        fun trialDurationDays(trialDurationDays: JsonField<Long>) = apply {
+            body.trialDurationDays(trialDurationDays)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -1528,25 +2507,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionSchedulePlanChangeParams =
             SubscriptionSchedulePlanChangeParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
@@ -1623,16 +2583,49 @@ constructor(
     class AddAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment") private val adjustment: Adjustment,
-        @JsonProperty("end_date") private val endDate: OffsetDateTime?,
-        @JsonProperty("plan_phase_order") private val planPhaseOrder: Long?,
-        @JsonProperty("start_date") private val startDate: OffsetDateTime?,
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        private val adjustment: JsonField<Adjustment> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        private val planPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The definition of a new adjustment to create and add to the subscription. */
-        @JsonProperty("adjustment") fun adjustment(): Adjustment = adjustment
+        fun adjustment(): Adjustment = adjustment.getRequired("adjustment")
+
+        /**
+         * The end date of the adjustment interval. This is the date that the adjustment will stop
+         * affecting prices on the subscription. If null, the adjustment will start when the phase
+         * or subscription starts.
+         */
+        fun endDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The phase to add this adjustment to. */
+        fun planPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(planPhaseOrder.getNullable("plan_phase_order"))
+
+        /**
+         * The start date of the adjustment interval. This is the date that the adjustment will
+         * start affecting prices on the subscription. If null, the adjustment will start when the
+         * phase or subscription starts.
+         */
+        fun startDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
+        /** The definition of a new adjustment to create and add to the subscription. */
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /**
          * The end date of the adjustment interval. This is the date that the adjustment will stop
@@ -1640,11 +2633,13 @@ constructor(
          * or subscription starts.
          */
         @JsonProperty("end_date")
-        fun endDate(): Optional<OffsetDateTime> = Optional.ofNullable(endDate)
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The phase to add this adjustment to. */
         @JsonProperty("plan_phase_order")
-        fun planPhaseOrder(): Optional<Long> = Optional.ofNullable(planPhaseOrder)
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
         /**
          * The start date of the adjustment interval. This is the date that the adjustment will
@@ -1652,12 +2647,25 @@ constructor(
          * phase or subscription starts.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<OffsetDateTime> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddAdjustment = apply {
+            if (!validated) {
+                adjustment()
+                endDate()
+                planPhaseOrder()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -1667,10 +2675,10 @@ constructor(
 
         class Builder {
 
-            private var adjustment: Adjustment? = null
-            private var endDate: OffsetDateTime? = null
-            private var planPhaseOrder: Long? = null
-            private var startDate: OffsetDateTime? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -1683,34 +2691,34 @@ constructor(
             }
 
             /** The definition of a new adjustment to create and add to the subscription. */
-            fun adjustment(adjustment: Adjustment) = apply { this.adjustment = adjustment }
+            fun adjustment(adjustment: Adjustment) = adjustment(JsonField.of(adjustment))
 
-            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewPercentageDiscount(newPercentageDiscount)
+            /** The definition of a new adjustment to create and add to the subscription. */
+            fun adjustment(adjustment: JsonField<Adjustment>) = apply {
+                this.adjustment = adjustment
             }
 
-            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewUsageDiscount(newUsageDiscount)
-            }
+            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) =
+                adjustment(Adjustment.ofNewPercentageDiscount(newPercentageDiscount))
 
-            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) = apply {
-                this.adjustment = Adjustment.ofNewAmountDiscount(newAmountDiscount)
-            }
+            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) =
+                adjustment(Adjustment.ofNewUsageDiscount(newUsageDiscount))
 
-            fun adjustment(newMinimum: Adjustment.NewMinimum) = apply {
-                this.adjustment = Adjustment.ofNewMinimum(newMinimum)
-            }
+            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) =
+                adjustment(Adjustment.ofNewAmountDiscount(newAmountDiscount))
 
-            fun adjustment(newMaximum: Adjustment.NewMaximum) = apply {
-                this.adjustment = Adjustment.ofNewMaximum(newMaximum)
-            }
+            fun adjustment(newMinimum: Adjustment.NewMinimum) =
+                adjustment(Adjustment.ofNewMinimum(newMinimum))
+
+            fun adjustment(newMaximum: Adjustment.NewMaximum) =
+                adjustment(Adjustment.ofNewMaximum(newMaximum))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
              * stop affecting prices on the subscription. If null, the adjustment will start when
              * the phase or subscription starts.
              */
-            fun endDate(endDate: OffsetDateTime?) = apply { this.endDate = endDate }
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the adjustment interval. This is the date that the adjustment will
@@ -1719,10 +2727,16 @@ constructor(
              */
             fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
+            /**
+             * The end date of the adjustment interval. This is the date that the adjustment will
+             * stop affecting prices on the subscription. If null, the adjustment will start when
+             * the phase or subscription starts.
+             */
+            fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
+
             /** The phase to add this adjustment to. */
-            fun planPhaseOrder(planPhaseOrder: Long?) = apply {
-                this.planPhaseOrder = planPhaseOrder
-            }
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
 
             /** The phase to add this adjustment to. */
             fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
@@ -1732,12 +2746,17 @@ constructor(
             fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
                 planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
+            /** The phase to add this adjustment to. */
+            fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
+                this.planPhaseOrder = planPhaseOrder
+            }
+
             /**
              * The start date of the adjustment interval. This is the date that the adjustment will
              * start affecting prices on the subscription. If null, the adjustment will start when
              * the phase or subscription starts.
              */
-            fun startDate(startDate: OffsetDateTime?) = apply { this.startDate = startDate }
+            fun startDate(startDate: OffsetDateTime?) = startDate(JsonField.ofNullable(startDate))
 
             /**
              * The start date of the adjustment interval. This is the date that the adjustment will
@@ -1746,6 +2765,15 @@ constructor(
              */
             fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+            /**
+             * The start date of the adjustment interval. This is the date that the adjustment will
+             * start affecting prices on the subscription. If null, the adjustment will start when
+             * the phase or subscription starts.
+             */
+            fun startDate(startDate: JsonField<OffsetDateTime>) = apply {
+                this.startDate = startDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -1788,6 +2816,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newPercentageDiscount(): Optional<NewPercentageDiscount> =
                 Optional.ofNullable(newPercentageDiscount)
 
@@ -1838,6 +2868,26 @@ constructor(
                 }
             }
 
+            fun validate(): Adjustment = apply {
+                if (!validated) {
+                    if (
+                        newPercentageDiscount == null &&
+                            newUsageDiscount == null &&
+                            newAmountDiscount == null &&
+                            newMinimum == null &&
+                            newMaximum == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Adjustment: $_json")
+                    }
+                    newPercentageDiscount?.validate()
+                    newUsageDiscount?.validate()
+                    newAmountDiscount?.validate()
+                    newMinimum?.validate()
+                    newMaximum?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -1907,29 +2957,40 @@ constructor(
 
                     when (adjustmentType) {
                         "percentage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>())?.let {
-                                return Adjustment(newPercentageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newPercentageDiscount = it, _json = json)
+                                }
                         }
                         "usage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>())?.let {
-                                return Adjustment(newUsageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newUsageDiscount = it, _json = json)
+                                }
                         }
                         "amount_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>())?.let {
-                                return Adjustment(newAmountDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newAmountDiscount = it, _json = json)
+                                }
                         }
                         "minimum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMinimum>())?.let {
-                                return Adjustment(newMinimum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMinimum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMinimum = it, _json = json)
+                                }
                         }
                         "maximum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMaximum>())?.let {
-                                return Adjustment(newMaximum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMaximum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMaximum = it, _json = json)
+                                }
                         }
                     }
 
@@ -1963,35 +3024,75 @@ constructor(
             class NewPercentageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewPercentageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        percentageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2001,47 +3102,58 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var percentageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newPercentageDiscount: NewPercentageDiscount) = apply {
                         adjustmentType = newPercentageDiscount.adjustmentType
-                        appliesToPriceIds = newPercentageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newPercentageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         percentageDiscount = newPercentageDiscount.percentageDiscount
                         isInvoiceLevel = newPercentageDiscount.isInvoiceLevel
                         additionalProperties =
                             newPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
-                        this.percentageDiscount = percentageDiscount
-                    }
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                        this.percentageDiscount = percentageDiscount
                     }
 
                     /**
@@ -2049,15 +3161,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2089,7 +3201,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(percentageDiscount) {
                                 "`percentageDiscount` is required but was not set"
                             },
@@ -2172,34 +3284,74 @@ constructor(
             class NewUsageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewUsageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        usageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2209,46 +3361,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var usageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var usageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newUsageDiscount: NewUsageDiscount) = apply {
                         adjustmentType = newUsageDiscount.adjustmentType
-                        appliesToPriceIds = newUsageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newUsageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         usageDiscount = newUsageDiscount.usageDiscount
                         isInvoiceLevel = newUsageDiscount.isInvoiceLevel
                         additionalProperties = newUsageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun usageDiscount(usageDiscount: Double) = apply {
-                        this.usageDiscount = usageDiscount
-                    }
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                        this.usageDiscount = usageDiscount
                     }
 
                     /**
@@ -2256,15 +3419,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2296,7 +3459,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(usageDiscount) {
                                 "`usageDiscount` is required but was not set"
                             },
@@ -2379,34 +3542,74 @@ constructor(
             class NewAmountDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("amount_discount") private val amountDiscount: String,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
-                @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewAmountDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        amountDiscount()
+                        appliesToPriceIds()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2416,46 +3619,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var amountDiscount: String? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newAmountDiscount: NewAmountDiscount) = apply {
                         adjustmentType = newAmountDiscount.adjustmentType
                         amountDiscount = newAmountDiscount.amountDiscount
-                        appliesToPriceIds = newAmountDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newAmountDiscount.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = newAmountDiscount.isInvoiceLevel
                         additionalProperties = newAmountDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
-                    fun amountDiscount(amountDiscount: String) = apply {
+                    fun amountDiscount(amountDiscount: String) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
-                    }
-
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2463,15 +3677,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2506,7 +3720,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             isInvoiceLevel,
                             additionalProperties.toImmutable(),
                         )
@@ -2586,38 +3800,84 @@ constructor(
             class NewMinimum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /** The item ID that revenue from this minimum will be attributed to. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMinimum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        itemId()
+                        minimumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2627,51 +3887,64 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var itemId: String? = null
-                    private var minimumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMinimum: NewMinimum) = apply {
                         adjustmentType = newMinimum.adjustmentType
-                        appliesToPriceIds = newMinimum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMinimum.appliesToPriceIds.map { it.toMutableList() }
                         itemId = newMinimum.itemId
                         minimumAmount = newMinimum.minimumAmount
                         isInvoiceLevel = newMinimum.isInvoiceLevel
                         additionalProperties = newMinimum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /** The item ID that revenue from this minimum will be attributed to. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun minimumAmount(minimumAmount: String) = apply {
-                        this.minimumAmount = minimumAmount
-                    }
+                    /** The item ID that revenue from this minimum will be attributed to. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                        this.minimumAmount = minimumAmount
                     }
 
                     /**
@@ -2679,15 +3952,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2719,7 +3992,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(itemId) { "`itemId` is required but was not set" },
                             checkNotNull(minimumAmount) {
                                 "`minimumAmount` is required but was not set"
@@ -2803,34 +4076,74 @@ constructor(
             class NewMaximum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("maximum_amount") private val maximumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun maximumAmount(): String = maximumAmount.getRequired("maximum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("maximum_amount") fun maximumAmount(): String = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMaximum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        maximumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -2840,46 +4153,56 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var maximumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMaximum: NewMaximum) = apply {
                         adjustmentType = newMaximum.adjustmentType
-                        appliesToPriceIds = newMaximum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMaximum.appliesToPriceIds.map { it.toMutableList() }
                         maximumAmount = newMaximum.maximumAmount
                         isInvoiceLevel = newMaximum.isInvoiceLevel
                         additionalProperties = newMaximum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun maximumAmount(maximumAmount: String) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String) =
+                        maximumAmount(JsonField.of(maximumAmount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
                     /**
@@ -2887,15 +4210,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -2927,7 +4250,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(maximumAmount) {
                                 "`maximumAmount` is required but was not set"
                             },
@@ -3029,71 +4352,161 @@ constructor(
     class AddPrice
     @JsonCreator
     private constructor(
-        @JsonProperty("discounts") private val discounts: List<Discount>?,
-        @JsonProperty("end_date") private val endDate: OffsetDateTime?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-        @JsonProperty("minimum_amount") private val minimumAmount: String?,
-        @JsonProperty("plan_phase_order") private val planPhaseOrder: Long?,
-        @JsonProperty("price") private val price: Price?,
-        @JsonProperty("price_id") private val priceId: String?,
-        @JsonProperty("start_date") private val startDate: OffsetDateTime?,
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        private val discounts: JsonField<List<Discount>> = JsonMissing.of(),
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        private val endDate: JsonField<OffsetDateTime> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("plan_phase_order")
+        @ExcludeMissing
+        private val planPhaseOrder: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("price")
+        @ExcludeMissing
+        private val price: JsonField<Price> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        private val startDate: JsonField<OffsetDateTime> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this price.
+         */
+        fun discounts(): Optional<List<Discount>> =
+            Optional.ofNullable(discounts.getNullable("discounts"))
+
+        /**
+         * The end date of the price interval. This is the date that the price will stop billing on
+         * the subscription. If null, billing will end when the phase or subscription ends.
+         */
+        fun endDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(endDate.getNullable("end_date"))
+
+        /** The external price id of the price to add to the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
+         * price.
+         */
+        fun maximumAmount(): Optional<String> =
+            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
+         * price.
+         */
+        fun minimumAmount(): Optional<String> =
+            Optional.ofNullable(minimumAmount.getNullable("minimum_amount"))
+
+        /** The phase to add this price to. */
+        fun planPhaseOrder(): Optional<Long> =
+            Optional.ofNullable(planPhaseOrder.getNullable("plan_phase_order"))
+
+        /** The definition of a new price to create and add to the subscription. */
+        fun price(): Optional<Price> = Optional.ofNullable(price.getNullable("price"))
+
+        /** The id of the price to add to the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
+        /**
+         * The start date of the price interval. This is the date that the price will start billing
+         * on the subscription. If null, billing will start when the phase or subscription starts.
+         */
+        fun startDate(): Optional<OffsetDateTime> =
+            Optional.ofNullable(startDate.getNullable("start_date"))
+
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this price.
          */
         @JsonProperty("discounts")
-        fun discounts(): Optional<List<Discount>> = Optional.ofNullable(discounts)
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         /**
          * The end date of the price interval. This is the date that the price will stop billing on
          * the subscription. If null, billing will end when the phase or subscription ends.
          */
         @JsonProperty("end_date")
-        fun endDate(): Optional<OffsetDateTime> = Optional.ofNullable(endDate)
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The external price id of the price to add to the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
          * price.
          */
         @JsonProperty("maximum_amount")
-        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
          * price.
          */
         @JsonProperty("minimum_amount")
-        fun minimumAmount(): Optional<String> = Optional.ofNullable(minimumAmount)
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The phase to add this price to. */
         @JsonProperty("plan_phase_order")
-        fun planPhaseOrder(): Optional<Long> = Optional.ofNullable(planPhaseOrder)
+        @ExcludeMissing
+        fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
         /** The definition of a new price to create and add to the subscription. */
-        @JsonProperty("price") fun price(): Optional<Price> = Optional.ofNullable(price)
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /** The id of the price to add to the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         /**
          * The start date of the price interval. This is the date that the price will start billing
          * on the subscription. If null, billing will start when the phase or subscription starts.
          */
         @JsonProperty("start_date")
-        fun startDate(): Optional<OffsetDateTime> = Optional.ofNullable(startDate)
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): AddPrice = apply {
+            if (!validated) {
+                discounts().map { it.forEach { it.validate() } }
+                endDate()
+                externalPriceId()
+                maximumAmount()
+                minimumAmount()
+                planPhaseOrder()
+                price()
+                priceId()
+                startDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -3103,20 +4516,20 @@ constructor(
 
         class Builder {
 
-            private var discounts: MutableList<Discount>? = null
-            private var endDate: OffsetDateTime? = null
-            private var externalPriceId: String? = null
-            private var maximumAmount: String? = null
-            private var minimumAmount: String? = null
-            private var planPhaseOrder: Long? = null
-            private var price: Price? = null
-            private var priceId: String? = null
-            private var startDate: OffsetDateTime? = null
+            private var discounts: JsonField<MutableList<Discount>>? = null
+            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
+            private var price: JsonField<Price> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
+            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(addPrice: AddPrice) = apply {
-                discounts = addPrice.discounts?.toMutableList()
+                discounts = addPrice.discounts.map { it.toMutableList() }
                 endDate = addPrice.endDate
                 externalPriceId = addPrice.externalPriceId
                 maximumAmount = addPrice.maximumAmount
@@ -3132,9 +4545,7 @@ constructor(
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
              * price.
              */
-            fun discounts(discounts: List<Discount>?) = apply {
-                this.discounts = discounts?.toMutableList()
-            }
+            fun discounts(discounts: List<Discount>?) = discounts(JsonField.ofNullable(discounts))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
@@ -3142,19 +4553,36 @@ constructor(
              */
             fun discounts(discounts: Optional<List<Discount>>) = discounts(discounts.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
+             * price.
+             */
+            fun discounts(discounts: JsonField<List<Discount>>) = apply {
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for this
              * price.
              */
             fun addDiscount(discount: Discount) = apply {
-                discounts = (discounts ?: mutableListOf()).apply { add(discount) }
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
              * on the subscription. If null, billing will end when the phase or subscription ends.
              */
-            fun endDate(endDate: OffsetDateTime?) = apply { this.endDate = endDate }
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
 
             /**
              * The end date of the price interval. This is the date that the price will stop billing
@@ -3162,20 +4590,31 @@ constructor(
              */
             fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
+            /**
+             * The end date of the price interval. This is the date that the price will stop billing
+             * on the subscription. If null, billing will end when the phase or subscription ends.
+             */
+            fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
+
             /** The external price id of the price to add to the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to add to the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** The external price id of the price to add to the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
              * price.
              */
-            fun maximumAmount(maximumAmount: String?) = apply { this.maximumAmount = maximumAmount }
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
@@ -3184,11 +4623,20 @@ constructor(
             fun maximumAmount(maximumAmount: Optional<String>) =
                 maximumAmount(maximumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for this
+             * price.
+             */
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
              * price.
              */
-            fun minimumAmount(minimumAmount: String?) = apply { this.minimumAmount = minimumAmount }
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
@@ -3197,11 +4645,18 @@ constructor(
             fun minimumAmount(minimumAmount: Optional<String>) =
                 minimumAmount(minimumAmount.orElse(null))
 
-            /** The phase to add this price to. */
-            fun planPhaseOrder(planPhaseOrder: Long?) = apply {
-                this.planPhaseOrder = planPhaseOrder
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for this
+             * price.
+             */
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
             }
 
+            /** The phase to add this price to. */
+            fun planPhaseOrder(planPhaseOrder: Long?) =
+                planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
             /** The phase to add this price to. */
             fun planPhaseOrder(planPhaseOrder: Long) = planPhaseOrder(planPhaseOrder as Long?)
 
@@ -3210,144 +4665,144 @@ constructor(
             fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
                 planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
+            /** The phase to add this price to. */
+            fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
+                this.planPhaseOrder = planPhaseOrder
+            }
+
             /** The definition of a new price to create and add to the subscription. */
-            fun price(price: Price?) = apply { this.price = price }
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /** The definition of a new price to create and add to the subscription. */
             fun price(price: Optional<Price>) = price(price.orElse(null))
 
-            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) = apply {
-                this.price = Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice)
-            }
+            /** The definition of a new price to create and add to the subscription. */
+            fun price(price: JsonField<Price>) = apply { this.price = price }
 
-            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) = apply {
-                this.price = Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice)
-            }
+            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) =
+                price(Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice))
 
-            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) = apply {
-                this.price = Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice)
-            }
+            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) =
+                price(Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice))
 
-            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice)
-            }
+            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) =
+                price(Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice))
 
-            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice)
-            }
+            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) =
+                price(Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice))
 
-            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice)
-            }
+            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) =
+                price(Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice))
 
-            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice)
-            }
+            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) =
+                price(Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice))
 
-            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice)
-            }
+            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) =
+                price(Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice))
+
+            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) =
+                price(Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice))
 
             fun price(
                 newSubscriptionThresholdTotalAmountPrice:
                     Price.NewSubscriptionThresholdTotalAmountPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionThresholdTotalAmountPrice(
                         newSubscriptionThresholdTotalAmountPrice
                     )
-            }
+                )
 
             fun price(newSubscriptionTieredPackagePrice: Price.NewSubscriptionTieredPackagePrice) =
-                apply {
-                    this.price =
-                        Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice)
-                }
+                price(Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice))
 
             fun price(
                 newSubscriptionTieredWithMinimumPrice: Price.NewSubscriptionTieredWithMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTieredWithMinimumPrice(
                         newSubscriptionTieredWithMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithPercentPrice: Price.NewSubscriptionUnitWithPercentPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithPercentPrice(newSubscriptionUnitWithPercentPrice)
-            }
+                )
 
             fun price(
                 newSubscriptionPackageWithAllocationPrice:
                     Price.NewSubscriptionPackageWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionPackageWithAllocationPrice(
                         newSubscriptionPackageWithAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionTierWithProrationPrice: Price.NewSubscriptionTierWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTierWithProrationPrice(
                         newSubscriptionTierWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithProrationPrice: Price.NewSubscriptionUnitWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithProrationPrice(
                         newSubscriptionUnitWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedAllocationPrice: Price.NewSubscriptionGroupedAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedAllocationPrice(
                         newSubscriptionGroupedAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedWithProratedMinimumPrice:
                     Price.NewSubscriptionGroupedWithProratedMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedWithProratedMinimumPrice(
                         newSubscriptionGroupedWithProratedMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionBulkWithProrationPrice: Price.NewSubscriptionBulkWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionBulkWithProrationPrice(
                         newSubscriptionBulkWithProrationPrice
                     )
-            }
+                )
 
             /** The id of the price to add to the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to add to the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to add to the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             /**
              * The start date of the price interval. This is the date that the price will start
              * billing on the subscription. If null, billing will start when the phase or
              * subscription starts.
              */
-            fun startDate(startDate: OffsetDateTime?) = apply { this.startDate = startDate }
+            fun startDate(startDate: OffsetDateTime?) = startDate(JsonField.ofNullable(startDate))
 
             /**
              * The start date of the price interval. This is the date that the price will start
@@ -3356,6 +4811,15 @@ constructor(
              */
             fun startDate(startDate: Optional<OffsetDateTime>) = startDate(startDate.orElse(null))
 
+            /**
+             * The start date of the price interval. This is the date that the price will start
+             * billing on the subscription. If null, billing will start when the phase or
+             * subscription starts.
+             */
+            fun startDate(startDate: JsonField<OffsetDateTime>) = apply {
+                this.startDate = startDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -3377,7 +4841,7 @@ constructor(
 
             fun build(): AddPrice =
                 AddPrice(
-                    discounts?.toImmutable(),
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     endDate,
                     externalPriceId,
                     maximumAmount,
@@ -3394,37 +4858,81 @@ constructor(
         class Discount
         @JsonCreator
         private constructor(
-            @JsonProperty("discount_type") private val discountType: DiscountType,
-            @JsonProperty("amount_discount") private val amountDiscount: String?,
-            @JsonProperty("percentage_discount") private val percentageDiscount: Double?,
-            @JsonProperty("usage_discount") private val usageDiscount: Double?,
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            private val amountDiscount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("percentage_discount")
+            @ExcludeMissing
+            private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            private val usageDiscount: JsonField<Double> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+            /** Only available if discount_type is `amount`. */
+            fun amountDiscount(): Optional<String> =
+                Optional.ofNullable(amountDiscount.getNullable("amount_discount"))
+
+            /**
+             * Only available if discount_type is `percentage`. This is a number between 0 and 1.
+             */
+            fun percentageDiscount(): Optional<Double> =
+                Optional.ofNullable(percentageDiscount.getNullable("percentage_discount"))
+
+            /**
+             * Only available if discount_type is `usage`. Number of usage units that this discount
+             * is for
+             */
+            fun usageDiscount(): Optional<Double> =
+                Optional.ofNullable(usageDiscount.getNullable("usage_discount"))
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** Only available if discount_type is `amount`. */
             @JsonProperty("amount_discount")
-            fun amountDiscount(): Optional<String> = Optional.ofNullable(amountDiscount)
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /**
              * Only available if discount_type is `percentage`. This is a number between 0 and 1.
              */
             @JsonProperty("percentage_discount")
-            fun percentageDiscount(): Optional<Double> = Optional.ofNullable(percentageDiscount)
+            @ExcludeMissing
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
             @JsonProperty("usage_discount")
-            fun usageDiscount(): Optional<Double> = Optional.ofNullable(usageDiscount)
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Discount = apply {
+                if (!validated) {
+                    discountType()
+                    amountDiscount()
+                    percentageDiscount()
+                    usageDiscount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -3434,10 +4942,10 @@ constructor(
 
             class Builder {
 
-                private var discountType: DiscountType? = null
-                private var amountDiscount: String? = null
-                private var percentageDiscount: Double? = null
-                private var usageDiscount: Double? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var amountDiscount: JsonField<String> = JsonMissing.of()
+                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+                private var usageDiscount: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -3449,26 +4957,32 @@ constructor(
                     additionalProperties = discount.additionalProperties.toMutableMap()
                 }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
                 /** Only available if discount_type is `amount`. */
-                fun amountDiscount(amountDiscount: String?) = apply {
-                    this.amountDiscount = amountDiscount
-                }
+                fun amountDiscount(amountDiscount: String?) =
+                    amountDiscount(JsonField.ofNullable(amountDiscount))
 
                 /** Only available if discount_type is `amount`. */
                 fun amountDiscount(amountDiscount: Optional<String>) =
                     amountDiscount(amountDiscount.orElse(null))
 
+                /** Only available if discount_type is `amount`. */
+                fun amountDiscount(amountDiscount: JsonField<String>) = apply {
+                    this.amountDiscount = amountDiscount
+                }
+
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
                  * and 1.
                  */
-                fun percentageDiscount(percentageDiscount: Double?) = apply {
-                    this.percentageDiscount = percentageDiscount
-                }
+                fun percentageDiscount(percentageDiscount: Double?) =
+                    percentageDiscount(JsonField.ofNullable(percentageDiscount))
 
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
@@ -3485,13 +4999,20 @@ constructor(
                 fun percentageDiscount(percentageDiscount: Optional<Double>) =
                     percentageDiscount(percentageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `percentage`. This is a number between 0
+                 * and 1.
+                 */
+                fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                    this.percentageDiscount = percentageDiscount
+                }
+
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
                  * discount is for
                  */
-                fun usageDiscount(usageDiscount: Double?) = apply {
-                    this.usageDiscount = usageDiscount
-                }
+                fun usageDiscount(usageDiscount: Double?) =
+                    usageDiscount(JsonField.ofNullable(usageDiscount))
 
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
@@ -3507,6 +5028,14 @@ constructor(
                 fun usageDiscount(usageDiscount: Optional<Double>) =
                     usageDiscount(usageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `usage`. Number of usage units that this
+                 * discount is for
+                 */
+                fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                    this.usageDiscount = usageDiscount
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -3664,6 +5193,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newSubscriptionUnitPrice(): Optional<NewSubscriptionUnitPrice> =
                 Optional.ofNullable(newSubscriptionUnitPrice)
 
@@ -3912,6 +5443,52 @@ constructor(
                 }
             }
 
+            fun validate(): Price = apply {
+                if (!validated) {
+                    if (
+                        newSubscriptionUnitPrice == null &&
+                            newSubscriptionPackagePrice == null &&
+                            newSubscriptionMatrixPrice == null &&
+                            newSubscriptionTieredPrice == null &&
+                            newSubscriptionTieredBpsPrice == null &&
+                            newSubscriptionBpsPrice == null &&
+                            newSubscriptionBulkBpsPrice == null &&
+                            newSubscriptionBulkPrice == null &&
+                            newSubscriptionThresholdTotalAmountPrice == null &&
+                            newSubscriptionTieredPackagePrice == null &&
+                            newSubscriptionTieredWithMinimumPrice == null &&
+                            newSubscriptionUnitWithPercentPrice == null &&
+                            newSubscriptionPackageWithAllocationPrice == null &&
+                            newSubscriptionTierWithProrationPrice == null &&
+                            newSubscriptionUnitWithProrationPrice == null &&
+                            newSubscriptionGroupedAllocationPrice == null &&
+                            newSubscriptionGroupedWithProratedMinimumPrice == null &&
+                            newSubscriptionBulkWithProrationPrice == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Price: $_json")
+                    }
+                    newSubscriptionUnitPrice?.validate()
+                    newSubscriptionPackagePrice?.validate()
+                    newSubscriptionMatrixPrice?.validate()
+                    newSubscriptionTieredPrice?.validate()
+                    newSubscriptionTieredBpsPrice?.validate()
+                    newSubscriptionBpsPrice?.validate()
+                    newSubscriptionBulkBpsPrice?.validate()
+                    newSubscriptionBulkPrice?.validate()
+                    newSubscriptionThresholdTotalAmountPrice?.validate()
+                    newSubscriptionTieredPackagePrice?.validate()
+                    newSubscriptionTieredWithMinimumPrice?.validate()
+                    newSubscriptionUnitWithPercentPrice?.validate()
+                    newSubscriptionPackageWithAllocationPrice?.validate()
+                    newSubscriptionTierWithProrationPrice?.validate()
+                    newSubscriptionUnitWithProrationPrice?.validate()
+                    newSubscriptionGroupedAllocationPrice?.validate()
+                    newSubscriptionGroupedWithProratedMinimumPrice?.validate()
+                    newSubscriptionBulkWithProrationPrice?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -4180,55 +5757,76 @@ constructor(
 
                     when (modelType) {
                         "unit" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>())?.let {
-                                return Price(newSubscriptionUnitPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionUnitPrice = it, _json = json)
+                                }
                         }
                         "package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionPackagePrice = it, _json = json)
                                 }
                         }
                         "matrix" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionMatrixPrice = it, _json = json)
                                 }
                         }
                         "tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredPrice = it, _json = json)
                                 }
                         }
                         "tiered_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredBpsPrice = it, _json = json)
                                 }
                         }
                         "bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>())?.let {
-                                return Price(newSubscriptionBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionBulkBpsPrice = it, _json = json)
                                 }
                         }
                         "bulk" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>())?.let {
-                                return Price(newSubscriptionBulkPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBulkPrice = it, _json = json)
+                                }
                         }
                         "threshold_total_amount" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionThresholdTotalAmountPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionThresholdTotalAmountPrice = it,
@@ -4240,7 +5838,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredPackagePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredPackagePrice = it,
@@ -4252,7 +5852,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredWithMinimumPrice = it,
@@ -4264,7 +5866,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithPercentPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithPercentPrice = it,
@@ -4276,7 +5880,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionPackageWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionPackageWithAllocationPrice = it,
@@ -4288,7 +5894,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTierWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTierWithProrationPrice = it,
@@ -4300,7 +5908,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithProrationPrice = it,
@@ -4312,7 +5922,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedAllocationPrice = it,
@@ -4324,7 +5936,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedWithProratedMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedWithProratedMinimumPrice = it,
@@ -4336,7 +5950,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionBulkWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionBulkWithProrationPrice = it,
@@ -4406,96 +6022,229 @@ constructor(
             class NewSubscriptionUnitPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+                fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -4503,19 +6252,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -4525,22 +6300,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitConfig: UnitConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitConfig: JsonField<UnitConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -4568,25 +6346,41 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
-                    fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                    fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
+
+                    fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                        this.unitConfig = unitConfig
+                    }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -4595,13 +6389,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -4618,13 +6419,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -4634,12 +6443,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -4654,11 +6470,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -4666,22 +6489,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -4698,22 +6530,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -4723,12 +6570,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -4737,11 +6592,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -4750,6 +6613,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -4932,18 +6803,34 @@ constructor(
                 class UnitConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Rate per unit of usage */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Rate per unit of usage */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitConfig = apply {
+                        if (!validated) {
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -4953,7 +6840,7 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -4964,7 +6851,12 @@ constructor(
                         }
 
                         /** Rate per unit of usage */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Rate per unit of usage */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -5023,22 +6915,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5048,8 +6964,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5063,10 +6979,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -5187,22 +7110,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5212,8 +7159,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -5228,10 +7175,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -5361,6 +7315,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -5442,96 +7404,229 @@ constructor(
             class NewSubscriptionPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_config") private val packageConfig: PackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -5539,19 +7634,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -5561,22 +7682,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageConfig: PackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageConfig: JsonField<PackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -5605,17 +7729,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun packageConfig(packageConfig: PackageConfig) =
+                        packageConfig(JsonField.of(packageConfig))
 
-                    fun packageConfig(packageConfig: PackageConfig) = apply {
+                    fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                         this.packageConfig = packageConfig
                     }
 
@@ -5623,9 +7763,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -5634,13 +7773,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -5657,13 +7803,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -5673,12 +7827,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -5693,11 +7854,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -5705,22 +7873,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -5737,22 +7914,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -5762,12 +7954,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -5776,11 +7976,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -5789,6 +7997,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -5973,25 +8189,52 @@ constructor(
                 class PackageConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("package_amount") private val packageAmount: String,
-                    @JsonProperty("package_size") private val packageSize: Long,
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    private val packageAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    private val packageSize: JsonField<Long> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** A currency amount to rate usage by */
-                    @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                    fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                    /** A currency amount to rate usage by */
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    fun _packageAmount(): JsonField<String> = packageAmount
 
                     /**
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    fun _packageSize(): JsonField<Long> = packageSize
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageConfig = apply {
+                        if (!validated) {
+                            packageAmount()
+                            packageSize()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6001,8 +8244,8 @@ constructor(
 
                     class Builder {
 
-                        private var packageAmount: String? = null
-                        private var packageSize: Long? = null
+                        private var packageAmount: JsonField<String>? = null
+                        private var packageSize: JsonField<Long>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6014,7 +8257,11 @@ constructor(
                         }
 
                         /** A currency amount to rate usage by */
-                        fun packageAmount(packageAmount: String) = apply {
+                        fun packageAmount(packageAmount: String) =
+                            packageAmount(JsonField.of(packageAmount))
+
+                        /** A currency amount to rate usage by */
+                        fun packageAmount(packageAmount: JsonField<String>) = apply {
                             this.packageAmount = packageAmount
                         }
 
@@ -6022,7 +8269,13 @@ constructor(
                          * An integer amount to represent package size. For example, 1000 here would
                          * divide usage by 1000 before multiplying by package_amount in rating
                          */
-                        fun packageSize(packageSize: Long) = apply {
+                        fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                        /**
+                         * An integer amount to represent package size. For example, 1000 here would
+                         * divide usage by 1000 before multiplying by package_amount in rating
+                         */
+                        fun packageSize(packageSize: JsonField<Long>) = apply {
                             this.packageSize = packageSize
                         }
 
@@ -6086,22 +8339,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6111,8 +8388,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6126,10 +8403,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -6250,22 +8534,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6275,8 +8583,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -6291,10 +8599,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -6424,6 +8739,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -6505,96 +8828,229 @@ constructor(
             class NewSubscriptionMatrixPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -6602,19 +9058,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionMatrixPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        matrixConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -6624,22 +9106,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var matrixConfig: MatrixConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -6668,27 +9153,42 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixConfig(matrixConfig: MatrixConfig) =
+                        matrixConfig(JsonField.of(matrixConfig))
 
-                    fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                    fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                         this.matrixConfig = matrixConfig
                     }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -6697,13 +9197,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -6720,13 +9227,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -6736,12 +9251,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -6756,11 +9278,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -6768,22 +9297,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -6800,22 +9338,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -6825,12 +9378,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -6839,11 +9400,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -6852,6 +9421,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -6984,31 +9561,66 @@ constructor(
                 class MatrixConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixConfig = apply {
+                        if (!validated) {
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7018,17 +9630,17 @@ constructor(
 
                     class Builder {
 
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
                             defaultUnitAmount = matrixConfig.defaultUnitAmount
-                            dimensions = matrixConfig.dimensions.toMutableList()
-                            matrixValues = matrixConfig.matrixValues.toMutableList()
+                            dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                            matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -7036,29 +9648,61 @@ constructor(
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -7091,11 +9735,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -7105,28 +9749,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -7136,14 +9807,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -7154,8 +9826,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -7165,13 +9845,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -7202,7 +9892,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -7306,22 +9996,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7331,8 +10045,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7346,10 +10060,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7470,22 +10191,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7495,8 +10240,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -7511,10 +10256,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -7644,6 +10396,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -7725,96 +10485,229 @@ constructor(
             class NewSubscriptionTieredPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+                fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -7822,19 +10715,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -7844,22 +10763,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredConfig: TieredConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredConfig: JsonField<TieredConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -7888,17 +10810,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredConfig(tieredConfig: TieredConfig) =
+                        tieredConfig(JsonField.of(tieredConfig))
 
-                    fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                    fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                         this.tieredConfig = tieredConfig
                     }
 
@@ -7906,9 +10844,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -7917,13 +10854,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -7940,13 +10884,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -7956,12 +10908,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -7976,11 +10935,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -7988,22 +10954,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -8020,22 +10995,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -8045,12 +11035,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -8059,11 +11057,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -8072,6 +11078,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -8256,18 +11270,34 @@ constructor(
                 class TieredConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8277,26 +11307,42 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredConfig: TieredConfig) = apply {
-                            tiers = tieredConfig.tiers.toMutableList()
+                            tiers = tieredConfig.tiers.map { it.toMutableList() }
                             additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                         }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for rating based on total usage quantities into the specified tier
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -8324,7 +11370,7 @@ constructor(
                         fun build(): TieredConfig =
                             TieredConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -8333,30 +11379,64 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("first_unit") private val firstUnit: Double,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("last_unit") private val lastUnit: Double?,
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("last_unit")
+                        @ExcludeMissing
+                        private val lastUnit: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                        fun firstUnit(): Double = firstUnit.getRequired("first_unit")
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(): Optional<Double> =
+                            Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        fun _firstUnit(): JsonField<Double> = firstUnit
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
                         @JsonProperty("last_unit")
-                        fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                        @ExcludeMissing
+                        fun _lastUnit(): JsonField<Double> = lastUnit
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                firstUnit()
+                                unitAmount()
+                                lastUnit()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -8366,9 +11446,9 @@ constructor(
 
                         class Builder {
 
-                            private var firstUnit: Double? = null
-                            private var unitAmount: String? = null
-                            private var lastUnit: Double? = null
+                            private var firstUnit: JsonField<Double>? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var lastUnit: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -8381,10 +11461,19 @@ constructor(
                             }
 
                             /** Inclusive tier starting value */
-                            fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                            fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                            /** Inclusive tier starting value */
+                            fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                                this.firstUnit = firstUnit
+                            }
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -8392,7 +11481,8 @@ constructor(
                              * Exclusive tier ending value. If null, this is treated as the last
                              * tier
                              */
-                            fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                            fun lastUnit(lastUnit: Double?) =
+                                lastUnit(JsonField.ofNullable(lastUnit))
 
                             /**
                              * Exclusive tier ending value. If null, this is treated as the last
@@ -8410,6 +11500,14 @@ constructor(
                             fun lastUnit(lastUnit: Optional<Double>) =
                                 lastUnit(lastUnit.orElse(null) as Double?)
 
+                            /**
+                             * Exclusive tier ending value. If null, this is treated as the last
+                             * tier
+                             */
+                            fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                                this.lastUnit = lastUnit
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -8489,22 +11587,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8514,8 +11636,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8529,10 +11651,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8653,22 +11782,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8678,8 +11831,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -8694,10 +11847,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -8827,6 +11987,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -8908,97 +12076,230 @@ constructor(
             class NewSubscriptionTieredBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_bps_config")
+                @ExcludeMissing
+                private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredBpsConfig(): TieredBpsConfig =
+                    tieredBpsConfig.getRequired("tiered_bps_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_bps_config")
-                fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+                @ExcludeMissing
+                fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -9006,19 +12307,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredBpsPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredBpsConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -9028,22 +12355,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredBpsConfig: TieredBpsConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -9073,17 +12403,33 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                        tieredBpsConfig(JsonField.of(tieredBpsConfig))
 
-                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                    fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                         this.tieredBpsConfig = tieredBpsConfig
                     }
 
@@ -9091,9 +12437,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -9102,13 +12447,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -9125,13 +12477,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -9141,12 +12501,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -9161,11 +12528,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -9173,22 +12547,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -9205,22 +12588,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -9230,12 +12628,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -9244,11 +12650,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -9257,6 +12671,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -9441,7 +12863,9 @@ constructor(
                 class TieredBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -9450,12 +12874,29 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9465,13 +12906,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                            tiers = tieredBpsConfig.tiers.toMutableList()
+                            tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties =
                                 tieredBpsConfig.additionalProperties.toMutableMap()
                         }
@@ -9480,14 +12921,31 @@ constructor(
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                         * specified tiers
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -9515,7 +12973,7 @@ constructor(
                         fun build(): TieredBpsConfig =
                             TieredBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -9524,33 +12982,71 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("minimum_amount") private val minimumAmount: String,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Per-event basis point rate */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Inclusive tier starting value */
+                        fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Per-event basis point rate */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        fun _minimumAmount(): JsonField<String> = minimumAmount
 
                         /** Exclusive tier ending value */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** Per unit maximum to charge */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                minimumAmount()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -9560,10 +13056,10 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var minimumAmount: String? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var minimumAmount: JsonField<String>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -9577,31 +13073,46 @@ constructor(
                             }
 
                             /** Per-event basis point rate */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Per-event basis point rate */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
+
+                            /** Inclusive tier starting value */
+                            fun minimumAmount(minimumAmount: String) =
+                                minimumAmount(JsonField.of(minimumAmount))
 
                             /** Inclusive tier starting value */
-                            fun minimumAmount(minimumAmount: String) = apply {
+                            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                                 this.minimumAmount = minimumAmount
                             }
 
                             /** Exclusive tier ending value */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Exclusive tier ending value */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** Per unit maximum to charge */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Exclusive tier ending value */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** Per unit maximum to charge */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -9680,22 +13191,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9705,8 +13240,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9720,10 +13255,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -9844,22 +13386,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -9869,8 +13435,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -9885,10 +13451,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -10018,6 +13591,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10099,96 +13680,229 @@ constructor(
             class NewSubscriptionBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+                fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -10196,19 +13910,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBpsPrice = apply {
+                    if (!validated) {
+                        bpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -10218,22 +13958,25 @@ constructor(
 
                 class Builder {
 
-                    private var bpsConfig: BpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bpsConfig: JsonField<BpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -10260,26 +14003,42 @@ constructor(
                             newSubscriptionBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                    fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                    fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                        this.bpsConfig = bpsConfig
+                    }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -10288,13 +14047,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -10311,13 +14077,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -10327,12 +14101,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -10347,11 +14128,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -10359,22 +14147,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -10391,22 +14188,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -10416,12 +14228,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -10430,11 +14250,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -10443,6 +14271,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -10491,23 +14327,45 @@ constructor(
                 class BpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis point take rate per event */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis point take rate per event */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Optional currency amount maximum to cap spend per event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BpsConfig = apply {
+                        if (!validated) {
+                            bps()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10517,8 +14375,8 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10530,17 +14388,24 @@ constructor(
                         }
 
                         /** Basis point take rate per event */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis point take rate per event */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Optional currency amount maximum to cap spend per event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
-                        }
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                         /** Optional currency amount maximum to cap spend per event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Optional currency amount maximum to cap spend per event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -10731,22 +14596,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10756,8 +14645,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10771,10 +14660,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -10895,22 +14791,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -10920,8 +14840,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -10936,10 +14856,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -11069,6 +14996,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11150,96 +15085,229 @@ constructor(
             class NewSubscriptionBulkBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+                fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -11247,19 +15315,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkBpsPrice = apply {
+                    if (!validated) {
+                        bulkBpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -11269,22 +15363,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkBpsConfig: BulkBpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -11312,28 +15409,43 @@ constructor(
                                 newSubscriptionBulkBpsPrice.additionalProperties.toMutableMap()
                         }
 
-                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                        bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                    fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                         this.bulkBpsConfig = bulkBpsConfig
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -11342,13 +15454,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -11365,13 +15484,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -11381,12 +15508,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -11401,11 +15535,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -11413,22 +15554,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -11445,22 +15595,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -11470,12 +15635,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -11484,11 +15657,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -11497,6 +15678,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -11547,7 +15736,9 @@ constructor(
                 class BulkBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -11556,12 +15747,29 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11571,13 +15779,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                            tiers = bulkBpsConfig.tiers.toMutableList()
+                            tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                         }
 
@@ -11585,14 +15793,31 @@ constructor(
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a bulk BPS pricing model where all usage is aggregated to a
+                         * single tier based on total volume
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -11620,7 +15845,7 @@ constructor(
                         fun build(): BulkBpsConfig =
                             BulkBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -11629,29 +15854,59 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Basis points to rate on */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Upper bound for tier */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Basis points to rate on */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Upper bound for tier */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** The maximum amount to charge for any one event */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -11661,9 +15916,9 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -11676,26 +15931,37 @@ constructor(
                             }
 
                             /** Basis points to rate on */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Basis points to rate on */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Upper bound for tier */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Upper bound for tier */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** The maximum amount to charge for any one event */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Upper bound for tier */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** The maximum amount to charge for any one event */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -11905,22 +16171,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -11930,8 +16220,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -11945,10 +16235,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12069,22 +16366,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12094,8 +16415,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -12110,10 +16431,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -12243,6 +16571,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12324,96 +16660,229 @@ constructor(
             class NewSubscriptionBulkPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+                fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -12421,19 +16890,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkPrice = apply {
+                    if (!validated) {
+                        bulkConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -12443,22 +16938,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkConfig: BulkConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkConfig: JsonField<BulkConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -12485,26 +16983,42 @@ constructor(
                             newSubscriptionBulkPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                    fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                    fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                        this.bulkConfig = bulkConfig
+                    }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -12513,13 +17027,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -12536,13 +17057,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -12552,12 +17081,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -12572,11 +17108,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -12584,22 +17127,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -12616,22 +17168,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -12641,12 +17208,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -12655,11 +17230,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -12668,6 +17251,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -12716,18 +17307,34 @@ constructor(
                 class BulkConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Bulk tiers for rating based on total usage volume */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -12737,22 +17344,36 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkConfig: BulkConfig) = apply {
-                            tiers = bulkConfig.tiers.toMutableList()
+                            tiers = bulkConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                         }
 
                         /** Bulk tiers for rating based on total usage volume */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /** Bulk tiers for rating based on total usage volume */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /** Bulk tiers for rating based on total usage volume */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -12780,7 +17401,7 @@ constructor(
                         fun build(): BulkConfig =
                             BulkConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -12789,24 +17410,48 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_units")
+                        @ExcludeMissing
+                        private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /** Upper bound for this tier */
+                        fun maximumUnits(): Optional<Double> =
+                            Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /** Upper bound for this tier */
                         @JsonProperty("maximum_units")
-                        fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                        @ExcludeMissing
+                        fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                unitAmount()
+                                maximumUnits()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -12816,8 +17461,8 @@ constructor(
 
                         class Builder {
 
-                            private var unitAmount: String? = null
-                            private var maximumUnits: Double? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var maximumUnits: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -12829,14 +17474,17 @@ constructor(
                             }
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
                             /** Upper bound for this tier */
-                            fun maximumUnits(maximumUnits: Double?) = apply {
-                                this.maximumUnits = maximumUnits
-                            }
+                            fun maximumUnits(maximumUnits: Double?) =
+                                maximumUnits(JsonField.ofNullable(maximumUnits))
 
                             /** Upper bound for this tier */
                             fun maximumUnits(maximumUnits: Double) =
@@ -12849,6 +17497,11 @@ constructor(
                             fun maximumUnits(maximumUnits: Optional<Double>) =
                                 maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                            /** Upper bound for this tier */
+                            fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                                this.maximumUnits = maximumUnits
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -13059,22 +17712,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13084,8 +17761,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13099,10 +17776,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13223,22 +17907,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13248,8 +17956,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -13264,10 +17972,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -13397,6 +18112,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -13478,42 +18201,166 @@ constructor(
             class NewSubscriptionThresholdTotalAmountPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("threshold_total_amount_config")
-                private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("threshold_total_amount_config")
                 fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                    thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("threshold_total_amount_config")
+                @ExcludeMissing
+                fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                     thresholdTotalAmountConfig
 
                 /**
@@ -13521,56 +18368,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -13578,19 +18434,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionThresholdTotalAmountPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        thresholdTotalAmountConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -13600,22 +18482,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -13650,27 +18536,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun thresholdTotalAmountConfig(
                         thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                    ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                    fun thresholdTotalAmountConfig(
+                        thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                     ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -13679,13 +18581,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -13702,13 +18611,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -13718,12 +18635,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -13738,11 +18662,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -13750,22 +18681,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -13782,22 +18722,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -13807,12 +18762,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -13821,11 +18784,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -13834,6 +18805,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -14026,6 +19005,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): ThresholdTotalAmountConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14097,22 +19084,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14122,8 +19133,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14137,10 +19148,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14261,22 +19279,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14286,8 +19328,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -14302,10 +19344,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -14435,6 +19484,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -14516,98 +19573,230 @@ constructor(
             class NewSubscriptionTieredPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_package_config")
-                private val tieredPackageConfig: TieredPackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageConfig(): TieredPackageConfig =
+                    tieredPackageConfig.getRequired("tiered_package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_config")
-                fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+                @ExcludeMissing
+                fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -14615,19 +19804,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -14637,22 +19852,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageConfig: TieredPackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -14682,27 +19900,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                        this.tieredPackageConfig = tieredPackageConfig
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
                     }
 
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                        tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                    fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                        apply {
+                            this.tieredPackageConfig = tieredPackageConfig
+                        }
+
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -14711,13 +19945,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -14734,13 +19975,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -14750,12 +19999,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -14770,11 +20026,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -14782,22 +20045,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -14814,22 +20086,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -14839,12 +20126,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -14853,11 +20148,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -14866,6 +20169,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -15058,6 +20369,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15128,22 +20447,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15153,8 +20496,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15168,10 +20511,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15292,22 +20642,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15317,8 +20691,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -15333,10 +20707,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -15466,6 +20847,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -15547,98 +20936,232 @@ constructor(
             class NewSubscriptionTieredWithMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_minimum_config")
-                private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                    tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_minimum_config")
-                fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+                @ExcludeMissing
+                fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                    tieredWithMinimumConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -15646,19 +21169,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -15668,22 +21217,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -15717,28 +21269,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                        apply {
-                            this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                        }
+                        tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                    fun tieredWithMinimumConfig(
+                        tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                    ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -15747,13 +21313,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -15770,13 +21343,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -15786,12 +21367,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -15806,11 +21394,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -15818,22 +21413,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -15850,22 +21454,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -15875,12 +21494,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -15889,11 +21516,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -15902,6 +21537,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -16094,6 +21737,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16165,22 +21816,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16190,8 +21865,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16205,10 +21880,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16329,22 +22011,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16354,8 +22060,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -16370,10 +22076,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -16503,6 +22216,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -16584,98 +22305,232 @@ constructor(
             class NewSubscriptionUnitWithPercentPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_percent_config")
-                private val unitWithPercentConfig: UnitWithPercentConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithPercentConfig(): UnitWithPercentConfig =
+                    unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_percent_config")
-                fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+                @ExcludeMissing
+                fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> =
+                    unitWithPercentConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -16683,19 +22538,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithPercentPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithPercentConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -16705,22 +22586,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -16751,28 +22635,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
-                        apply {
-                            this.unitWithPercentConfig = unitWithPercentConfig
-                        }
+                        unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                    fun unitWithPercentConfig(
+                        unitWithPercentConfig: JsonField<UnitWithPercentConfig>
+                    ) = apply { this.unitWithPercentConfig = unitWithPercentConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -16781,13 +22679,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -16804,13 +22709,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -16820,12 +22733,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -16840,11 +22760,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -16852,22 +22779,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -16884,22 +22820,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -16909,12 +22860,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -16923,11 +22882,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -16936,6 +22903,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -17128,6 +23103,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithPercentConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17198,22 +23181,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17223,8 +23230,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17238,10 +23245,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17362,22 +23376,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17387,8 +23425,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -17403,10 +23441,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -17536,6 +23581,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -17617,42 +23670,166 @@ constructor(
             class NewSubscriptionPackageWithAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("package_with_allocation_config")
-                private val packageWithAllocationConfig: PackageWithAllocationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("package_with_allocation_config")
                 fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                    packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("package_with_allocation_config")
+                @ExcludeMissing
+                fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                     packageWithAllocationConfig
 
                 /**
@@ -17660,56 +23837,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -17717,19 +23903,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackageWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageWithAllocationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -17739,22 +23951,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageWithAllocationConfig:
+                        JsonField<PackageWithAllocationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -17790,27 +24007,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun packageWithAllocationConfig(
                         packageWithAllocationConfig: PackageWithAllocationConfig
+                    ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                    fun packageWithAllocationConfig(
+                        packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                     ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -17819,13 +24052,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -17842,13 +24082,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -17858,12 +24106,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -17878,11 +24133,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -17890,22 +24152,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -17922,22 +24193,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -17947,12 +24233,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -17961,11 +24255,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -17974,6 +24276,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -18166,6 +24476,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageWithAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18238,22 +24556,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18263,8 +24605,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18278,10 +24620,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18402,22 +24751,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18427,8 +24800,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -18443,10 +24816,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -18576,6 +24956,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -18657,42 +25045,166 @@ constructor(
             class NewSubscriptionTierWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_proration_config")
-                private val tieredWithProrationConfig: TieredWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_with_proration_config")
                 fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                    tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_with_proration_config")
+                @ExcludeMissing
+                fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
                     tieredWithProrationConfig
 
                 /**
@@ -18700,56 +25212,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -18757,19 +25278,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTierWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -18779,22 +25326,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -18828,27 +25379,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithProrationConfig(
                         tieredWithProrationConfig: TieredWithProrationConfig
+                    ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                    fun tieredWithProrationConfig(
+                        tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                     ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -18857,13 +25424,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -18880,13 +25454,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -18896,12 +25478,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -18916,11 +25505,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -18928,22 +25524,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -18960,22 +25565,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -18985,12 +25605,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -18999,11 +25627,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -19012,6 +25648,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -19204,6 +25848,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19275,22 +25927,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19300,8 +25976,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19315,10 +25991,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19439,22 +26122,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19464,8 +26171,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -19480,10 +26187,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -19613,6 +26327,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -19694,98 +26416,232 @@ constructor(
             class NewSubscriptionUnitWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_proration_config")
-                private val unitWithProrationConfig: UnitWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithProrationConfig(): UnitWithProrationConfig =
+                    unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_proration_config")
-                fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+                @ExcludeMissing
+                fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                    unitWithProrationConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -19793,19 +26649,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -19815,22 +26697,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -19864,28 +26749,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                        apply {
-                            this.unitWithProrationConfig = unitWithProrationConfig
-                        }
+                        unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                    fun unitWithProrationConfig(
+                        unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                    ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -19894,13 +26793,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -19917,13 +26823,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -19933,12 +26847,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -19953,11 +26874,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -19965,22 +26893,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -19997,22 +26934,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -20022,12 +26974,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -20036,11 +26996,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -20049,6 +27017,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -20241,6 +27217,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20312,22 +27296,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20337,8 +27345,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20352,10 +27360,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20476,22 +27491,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20501,8 +27540,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -20517,10 +27556,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -20650,6 +27696,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -20731,98 +27785,232 @@ constructor(
             class NewSubscriptionGroupedAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_allocation_config")
-                private val groupedAllocationConfig: GroupedAllocationConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                fun groupedAllocationConfig(): GroupedAllocationConfig =
+                    groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 @JsonProperty("grouped_allocation_config")
-                fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+                @ExcludeMissing
+                fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                    groupedAllocationConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -20830,19 +28018,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedAllocationConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -20852,22 +28066,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -20901,28 +28118,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                        apply {
-                            this.groupedAllocationConfig = groupedAllocationConfig
-                        }
+                        groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                    fun groupedAllocationConfig(
+                        groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                    ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -20931,13 +28162,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -20954,13 +28192,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -20970,12 +28216,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -20990,11 +28243,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -21002,22 +28262,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -21034,22 +28303,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -21059,12 +28343,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -21073,11 +28365,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -21086,6 +28386,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -21226,6 +28534,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21349,22 +28665,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21374,8 +28714,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21389,10 +28729,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21513,22 +28860,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21538,8 +28909,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -21554,10 +28925,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -21687,6 +29065,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -21768,99 +29154,235 @@ constructor(
             class NewSubscriptionGroupedWithProratedMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_with_prorated_minimum_config")
-                private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
-                @JsonProperty("grouped_with_prorated_minimum_config")
                 fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
-                    groupedWithProratedMinimumConfig
+                    groupedWithProratedMinimumConfig.getRequired(
+                        "grouped_with_prorated_minimum_config"
+                    )
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                @JsonProperty("grouped_with_prorated_minimum_config")
+                @ExcludeMissing
+                fun _groupedWithProratedMinimumConfig():
+                    JsonField<GroupedWithProratedMinimumConfig> = groupedWithProratedMinimumConfig
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -21868,19 +29390,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedWithProratedMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedWithProratedMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -21890,24 +29438,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
+                    private var cadence: JsonField<Cadence>? = null
                     private var groupedWithProratedMinimumConfig:
-                        GroupedWithProratedMinimumConfig? =
+                        JsonField<GroupedWithProratedMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -21948,29 +29499,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedWithProratedMinimumConfig(
                         groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                    ) =
+                        groupedWithProratedMinimumConfig(
+                            JsonField.of(groupedWithProratedMinimumConfig)
+                        )
+
+                    fun groupedWithProratedMinimumConfig(
+                        groupedWithProratedMinimumConfig:
+                            JsonField<GroupedWithProratedMinimumConfig>
                     ) = apply {
                         this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -21979,13 +29550,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -22002,13 +29580,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -22018,12 +29604,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -22038,11 +29631,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -22050,22 +29650,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -22082,22 +29691,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -22107,12 +29731,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -22121,11 +29753,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -22134,6 +29774,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -22274,6 +29922,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithProratedMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22399,22 +30055,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22424,8 +30104,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22439,10 +30119,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22563,22 +30250,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22588,8 +30299,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -22604,10 +30315,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -22737,6 +30455,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -22819,97 +30545,231 @@ constructor(
             @JsonCreator
             private constructor(
                 @JsonProperty("bulk_with_proration_config")
-                private val bulkWithProrationConfig: BulkWithProrationConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                    bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
                 @JsonProperty("bulk_with_proration_config")
-                fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+                @ExcludeMissing
+                fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                    bulkWithProrationConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -22917,19 +30777,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkWithProrationPrice = apply {
+                    if (!validated) {
+                        bulkWithProrationConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -22939,22 +30825,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -22988,28 +30877,42 @@ constructor(
                     }
 
                     fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                        apply {
-                            this.bulkWithProrationConfig = bulkWithProrationConfig
-                        }
+                        bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                    fun bulkWithProrationConfig(
+                        bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                    ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -23018,13 +30921,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -23041,13 +30951,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -23057,12 +30975,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -23077,11 +31002,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -23089,22 +31021,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -23121,22 +31062,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -23146,12 +31102,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -23160,11 +31124,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -23173,6 +31145,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -23231,6 +31211,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23436,22 +31424,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23461,8 +31473,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23476,10 +31488,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23600,22 +31619,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23625,8 +31668,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -23641,10 +31684,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -23774,6 +31824,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -23937,9 +31995,11 @@ constructor(
     class BillingCycleAnchorConfiguration
     @JsonCreator
     private constructor(
-        @JsonProperty("day") private val day: Long,
-        @JsonProperty("month") private val month: Long?,
-        @JsonProperty("year") private val year: Long?,
+        @JsonProperty("day") @ExcludeMissing private val day: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("month")
+        @ExcludeMissing
+        private val month: JsonField<Long> = JsonMissing.of(),
+        @JsonProperty("year") @ExcludeMissing private val year: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -23950,24 +32010,55 @@ constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") fun day(): Long = day
+        fun day(): Long = day.getRequired("day")
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") fun month(): Optional<Long> = Optional.ofNullable(month)
+        fun month(): Optional<Long> = Optional.ofNullable(month.getNullable("month"))
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") fun year(): Optional<Long> = Optional.ofNullable(year)
+        fun year(): Optional<Long> = Optional.ofNullable(year.getNullable("year"))
+
+        /**
+         * The day of the month on which the billing cycle is anchored. If the maximum number of
+         * days in a month is greater than this value, the last day of the month is the billing
+         * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
+         * 30th.
+         */
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
+
+        /**
+         * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+         * February would have cycles starting February, May, August, and November).
+         */
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
+
+        /**
+         * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
+         * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+         */
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): BillingCycleAnchorConfiguration = apply {
+            if (!validated) {
+                day()
+                month()
+                year()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -23977,9 +32068,9 @@ constructor(
 
         class Builder {
 
-            private var day: Long? = null
-            private var month: Long? = null
-            private var year: Long? = null
+            private var day: JsonField<Long>? = null
+            private var month: JsonField<Long> = JsonMissing.of()
+            private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -23998,13 +32089,21 @@ constructor(
              * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
              * 30th.
              */
-            fun day(day: Long) = apply { this.day = day }
+            fun day(day: Long) = day(JsonField.of(day))
+
+            /**
+             * The day of the month on which the billing cycle is anchored. If the maximum number of
+             * days in a month is greater than this value, the last day of the month is the billing
+             * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
+             * 30th.
+             */
+            fun day(day: JsonField<Long>) = apply { this.day = day }
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long?) = apply { this.month = month }
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -24019,11 +32118,17 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: JsonField<Long>) = apply { this.month = month }
+
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long?) = apply { this.year = year }
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -24038,6 +32143,12 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: JsonField<Long>) = apply { this.year = year }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -24088,18 +32199,34 @@ constructor(
     class RemoveAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment_id") private val adjustmentId: String,
+        @JsonProperty("adjustment_id")
+        @ExcludeMissing
+        private val adjustmentId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The id of the adjustment to remove on the subscription. */
-        @JsonProperty("adjustment_id") fun adjustmentId(): String = adjustmentId
+        fun adjustmentId(): String = adjustmentId.getRequired("adjustment_id")
+
+        /** The id of the adjustment to remove on the subscription. */
+        @JsonProperty("adjustment_id")
+        @ExcludeMissing
+        fun _adjustmentId(): JsonField<String> = adjustmentId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): RemoveAdjustment = apply {
+            if (!validated) {
+                adjustmentId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24109,7 +32236,7 @@ constructor(
 
         class Builder {
 
-            private var adjustmentId: String? = null
+            private var adjustmentId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24119,7 +32246,12 @@ constructor(
             }
 
             /** The id of the adjustment to remove on the subscription. */
-            fun adjustmentId(adjustmentId: String) = apply { this.adjustmentId = adjustmentId }
+            fun adjustmentId(adjustmentId: String) = adjustmentId(JsonField.of(adjustmentId))
+
+            /** The id of the adjustment to remove on the subscription. */
+            fun adjustmentId(adjustmentId: JsonField<String>) = apply {
+                this.adjustmentId = adjustmentId
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -24169,23 +32301,45 @@ constructor(
     class RemovePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("price_id") private val priceId: String?,
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /** The external price id of the price to remove on the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** The id of the price to remove on the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
         /** The external price id of the price to remove on the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** The id of the price to remove on the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): RemovePrice = apply {
+            if (!validated) {
+                externalPriceId()
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24195,8 +32349,8 @@ constructor(
 
         class Builder {
 
-            private var externalPriceId: String? = null
-            private var priceId: String? = null
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24207,20 +32361,27 @@ constructor(
             }
 
             /** The external price id of the price to remove on the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to remove on the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
+            /** The external price id of the price to remove on the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
+            }
+
             /** The id of the price to remove on the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to remove on the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to remove on the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -24270,23 +32431,47 @@ constructor(
     class ReplaceAdjustment
     @JsonCreator
     private constructor(
-        @JsonProperty("adjustment") private val adjustment: Adjustment,
-        @JsonProperty("replaces_adjustment_id") private val replacesAdjustmentId: String,
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        private val adjustment: JsonField<Adjustment> = JsonMissing.of(),
+        @JsonProperty("replaces_adjustment_id")
+        @ExcludeMissing
+        private val replacesAdjustmentId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The definition of a new adjustment to create and add to the subscription. */
-        @JsonProperty("adjustment") fun adjustment(): Adjustment = adjustment
+        fun adjustment(): Adjustment = adjustment.getRequired("adjustment")
+
+        /** The id of the adjustment on the plan to replace in the subscription. */
+        fun replacesAdjustmentId(): String =
+            replacesAdjustmentId.getRequired("replaces_adjustment_id")
+
+        /** The definition of a new adjustment to create and add to the subscription. */
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The id of the adjustment on the plan to replace in the subscription. */
         @JsonProperty("replaces_adjustment_id")
-        fun replacesAdjustmentId(): String = replacesAdjustmentId
+        @ExcludeMissing
+        fun _replacesAdjustmentId(): JsonField<String> = replacesAdjustmentId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReplaceAdjustment = apply {
+            if (!validated) {
+                adjustment()
+                replacesAdjustmentId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -24296,8 +32481,8 @@ constructor(
 
         class Builder {
 
-            private var adjustment: Adjustment? = null
-            private var replacesAdjustmentId: String? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var replacesAdjustmentId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -24308,30 +32493,34 @@ constructor(
             }
 
             /** The definition of a new adjustment to create and add to the subscription. */
-            fun adjustment(adjustment: Adjustment) = apply { this.adjustment = adjustment }
+            fun adjustment(adjustment: Adjustment) = adjustment(JsonField.of(adjustment))
 
-            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewPercentageDiscount(newPercentageDiscount)
+            /** The definition of a new adjustment to create and add to the subscription. */
+            fun adjustment(adjustment: JsonField<Adjustment>) = apply {
+                this.adjustment = adjustment
             }
 
-            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) = apply {
-                this.adjustment = Adjustment.ofNewUsageDiscount(newUsageDiscount)
-            }
+            fun adjustment(newPercentageDiscount: Adjustment.NewPercentageDiscount) =
+                adjustment(Adjustment.ofNewPercentageDiscount(newPercentageDiscount))
 
-            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) = apply {
-                this.adjustment = Adjustment.ofNewAmountDiscount(newAmountDiscount)
-            }
+            fun adjustment(newUsageDiscount: Adjustment.NewUsageDiscount) =
+                adjustment(Adjustment.ofNewUsageDiscount(newUsageDiscount))
 
-            fun adjustment(newMinimum: Adjustment.NewMinimum) = apply {
-                this.adjustment = Adjustment.ofNewMinimum(newMinimum)
-            }
+            fun adjustment(newAmountDiscount: Adjustment.NewAmountDiscount) =
+                adjustment(Adjustment.ofNewAmountDiscount(newAmountDiscount))
 
-            fun adjustment(newMaximum: Adjustment.NewMaximum) = apply {
-                this.adjustment = Adjustment.ofNewMaximum(newMaximum)
-            }
+            fun adjustment(newMinimum: Adjustment.NewMinimum) =
+                adjustment(Adjustment.ofNewMinimum(newMinimum))
+
+            fun adjustment(newMaximum: Adjustment.NewMaximum) =
+                adjustment(Adjustment.ofNewMaximum(newMaximum))
+
+            /** The id of the adjustment on the plan to replace in the subscription. */
+            fun replacesAdjustmentId(replacesAdjustmentId: String) =
+                replacesAdjustmentId(JsonField.of(replacesAdjustmentId))
 
             /** The id of the adjustment on the plan to replace in the subscription. */
-            fun replacesAdjustmentId(replacesAdjustmentId: String) = apply {
+            fun replacesAdjustmentId(replacesAdjustmentId: JsonField<String>) = apply {
                 this.replacesAdjustmentId = replacesAdjustmentId
             }
 
@@ -24377,6 +32566,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newPercentageDiscount(): Optional<NewPercentageDiscount> =
                 Optional.ofNullable(newPercentageDiscount)
 
@@ -24427,6 +32618,26 @@ constructor(
                 }
             }
 
+            fun validate(): Adjustment = apply {
+                if (!validated) {
+                    if (
+                        newPercentageDiscount == null &&
+                            newUsageDiscount == null &&
+                            newAmountDiscount == null &&
+                            newMinimum == null &&
+                            newMaximum == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Adjustment: $_json")
+                    }
+                    newPercentageDiscount?.validate()
+                    newUsageDiscount?.validate()
+                    newAmountDiscount?.validate()
+                    newMinimum?.validate()
+                    newMaximum?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -24496,29 +32707,40 @@ constructor(
 
                     when (adjustmentType) {
                         "percentage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>())?.let {
-                                return Adjustment(newPercentageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewPercentageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newPercentageDiscount = it, _json = json)
+                                }
                         }
                         "usage_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>())?.let {
-                                return Adjustment(newUsageDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewUsageDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newUsageDiscount = it, _json = json)
+                                }
                         }
                         "amount_discount" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>())?.let {
-                                return Adjustment(newAmountDiscount = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewAmountDiscount>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Adjustment(newAmountDiscount = it, _json = json)
+                                }
                         }
                         "minimum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMinimum>())?.let {
-                                return Adjustment(newMinimum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMinimum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMinimum = it, _json = json)
+                                }
                         }
                         "maximum" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewMaximum>())?.let {
-                                return Adjustment(newMaximum = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewMaximum>()) { it.validate() }
+                                ?.let {
+                                    return Adjustment(newMaximum = it, _json = json)
+                                }
                         }
                     }
 
@@ -24552,35 +32774,75 @@ constructor(
             class NewPercentageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("percentage_discount") private val percentageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("percentage_discount")
+                @ExcludeMissing
+                private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun percentageDiscount(): Double =
+                    percentageDiscount.getRequired("percentage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 @JsonProperty("percentage_discount")
-                fun percentageDiscount(): Double = percentageDiscount
+                @ExcludeMissing
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewPercentageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        percentageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -24590,47 +32852,58 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var percentageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newPercentageDiscount: NewPercentageDiscount) = apply {
                         adjustmentType = newPercentageDiscount.adjustmentType
-                        appliesToPriceIds = newPercentageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newPercentageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         percentageDiscount = newPercentageDiscount.percentageDiscount
                         isInvoiceLevel = newPercentageDiscount.isInvoiceLevel
                         additionalProperties =
                             newPercentageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun percentageDiscount(percentageDiscount: Double) = apply {
-                        this.percentageDiscount = percentageDiscount
-                    }
+                    fun percentageDiscount(percentageDiscount: Double) =
+                        percentageDiscount(JsonField.of(percentageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                        this.percentageDiscount = percentageDiscount
                     }
 
                     /**
@@ -24638,15 +32911,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -24678,7 +32951,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(percentageDiscount) {
                                 "`percentageDiscount` is required but was not set"
                             },
@@ -24761,34 +33034,74 @@ constructor(
             class NewUsageDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("usage_discount") private val usageDiscount: Double,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                private val usageDiscount: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("usage_discount") fun usageDiscount(): Double = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewUsageDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        usageDiscount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -24798,46 +33111,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var usageDiscount: Double? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var usageDiscount: JsonField<Double>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newUsageDiscount: NewUsageDiscount) = apply {
                         adjustmentType = newUsageDiscount.adjustmentType
-                        appliesToPriceIds = newUsageDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newUsageDiscount.appliesToPriceIds.map { it.toMutableList() }
                         usageDiscount = newUsageDiscount.usageDiscount
                         isInvoiceLevel = newUsageDiscount.isInvoiceLevel
                         additionalProperties = newUsageDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun usageDiscount(usageDiscount: Double) = apply {
-                        this.usageDiscount = usageDiscount
-                    }
+                    fun usageDiscount(usageDiscount: Double) =
+                        usageDiscount(JsonField.of(usageDiscount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                        this.usageDiscount = usageDiscount
                     }
 
                     /**
@@ -24845,15 +33169,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -24885,7 +33209,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(usageDiscount) {
                                 "`usageDiscount` is required but was not set"
                             },
@@ -24968,34 +33292,74 @@ constructor(
             class NewAmountDiscount
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("amount_discount") private val amountDiscount: String,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                private val amountDiscount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                fun amountDiscount(): String = amountDiscount.getRequired("amount_discount")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
-                @JsonProperty("amount_discount") fun amountDiscount(): String = amountDiscount
+                @JsonProperty("amount_discount")
+                @ExcludeMissing
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewAmountDiscount = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        amountDiscount()
+                        appliesToPriceIds()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25005,46 +33369,57 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var amountDiscount: String? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newAmountDiscount: NewAmountDiscount) = apply {
                         adjustmentType = newAmountDiscount.adjustmentType
                         amountDiscount = newAmountDiscount.amountDiscount
-                        appliesToPriceIds = newAmountDiscount.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds =
+                            newAmountDiscount.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = newAmountDiscount.isInvoiceLevel
                         additionalProperties = newAmountDiscount.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
-                    fun amountDiscount(amountDiscount: String) = apply {
+                    fun amountDiscount(amountDiscount: String) =
+                        amountDiscount(JsonField.of(amountDiscount))
+
+                    fun amountDiscount(amountDiscount: JsonField<String>) = apply {
                         this.amountDiscount = amountDiscount
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
-                    }
-
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -25052,15 +33427,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25095,7 +33470,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             isInvoiceLevel,
                             additionalProperties.toImmutable(),
                         )
@@ -25175,38 +33550,84 @@ constructor(
             class NewMinimum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("minimum_amount") private val minimumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                /** The item ID that revenue from this minimum will be attributed to. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMinimum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        itemId()
+                        minimumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25216,51 +33637,64 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var itemId: String? = null
-                    private var minimumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMinimum: NewMinimum) = apply {
                         adjustmentType = newMinimum.adjustmentType
-                        appliesToPriceIds = newMinimum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMinimum.appliesToPriceIds.map { it.toMutableList() }
                         itemId = newMinimum.itemId
                         minimumAmount = newMinimum.minimumAmount
                         isInvoiceLevel = newMinimum.isInvoiceLevel
                         additionalProperties = newMinimum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /** The item ID that revenue from this minimum will be attributed to. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun minimumAmount(minimumAmount: String) = apply {
-                        this.minimumAmount = minimumAmount
-                    }
+                    /** The item ID that revenue from this minimum will be attributed to. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun minimumAmount(minimumAmount: String) =
+                        minimumAmount(JsonField.of(minimumAmount))
+
+                    fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                        this.minimumAmount = minimumAmount
                     }
 
                     /**
@@ -25268,15 +33702,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25308,7 +33742,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(itemId) { "`itemId` is required but was not set" },
                             checkNotNull(minimumAmount) {
                                 "`minimumAmount` is required but was not set"
@@ -25392,34 +33826,74 @@ constructor(
             class NewMaximum
             @JsonCreator
             private constructor(
-                @JsonProperty("adjustment_type") private val adjustmentType: AdjustmentType,
-                @JsonProperty("applies_to_price_ids") private val appliesToPriceIds: List<String>,
-                @JsonProperty("maximum_amount") private val maximumAmount: String,
-                @JsonProperty("is_invoice_level") private val isInvoiceLevel: Boolean?,
+                @JsonProperty("adjustment_type")
+                @ExcludeMissing
+                private val adjustmentType: JsonField<AdjustmentType> = JsonMissing.of(),
+                @JsonProperty("applies_to_price_ids")
+                @ExcludeMissing
+                private val appliesToPriceIds: JsonField<List<String>> = JsonMissing.of(),
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("is_invoice_level")
+                @ExcludeMissing
+                private val isInvoiceLevel: JsonField<Boolean> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun adjustmentType(): AdjustmentType = adjustmentType.getRequired("adjustment_type")
+
+                /** The set of price IDs to which this adjustment applies. */
+                fun appliesToPriceIds(): List<String> =
+                    appliesToPriceIds.getRequired("applies_to_price_ids")
+
+                fun maximumAmount(): String = maximumAmount.getRequired("maximum_amount")
+
+                /**
+                 * When false, this adjustment will be applied to a single price. Otherwise, it will
+                 * be applied at the invoice level, possibly to multiple prices.
+                 */
+                fun isInvoiceLevel(): Optional<Boolean> =
+                    Optional.ofNullable(isInvoiceLevel.getNullable("is_invoice_level"))
+
                 @JsonProperty("adjustment_type")
-                fun adjustmentType(): AdjustmentType = adjustmentType
+                @ExcludeMissing
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The set of price IDs to which this adjustment applies. */
                 @JsonProperty("applies_to_price_ids")
-                fun appliesToPriceIds(): List<String> = appliesToPriceIds
+                @ExcludeMissing
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-                @JsonProperty("maximum_amount") fun maximumAmount(): String = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /**
                  * When false, this adjustment will be applied to a single price. Otherwise, it will
                  * be applied at the invoice level, possibly to multiple prices.
                  */
                 @JsonProperty("is_invoice_level")
-                fun isInvoiceLevel(): Optional<Boolean> = Optional.ofNullable(isInvoiceLevel)
+                @ExcludeMissing
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewMaximum = apply {
+                    if (!validated) {
+                        adjustmentType()
+                        appliesToPriceIds()
+                        maximumAmount()
+                        isInvoiceLevel()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -25429,46 +33903,56 @@ constructor(
 
                 class Builder {
 
-                    private var adjustmentType: AdjustmentType? = null
-                    private var appliesToPriceIds: MutableList<String>? = null
-                    private var maximumAmount: String? = null
-                    private var isInvoiceLevel: Boolean? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(newMaximum: NewMaximum) = apply {
                         adjustmentType = newMaximum.adjustmentType
-                        appliesToPriceIds = newMaximum.appliesToPriceIds.toMutableList()
+                        appliesToPriceIds = newMaximum.appliesToPriceIds.map { it.toMutableList() }
                         maximumAmount = newMaximum.maximumAmount
                         isInvoiceLevel = newMaximum.isInvoiceLevel
                         additionalProperties = newMaximum.additionalProperties.toMutableMap()
                     }
 
-                    fun adjustmentType(adjustmentType: AdjustmentType) = apply {
+                    fun adjustmentType(adjustmentType: AdjustmentType) =
+                        adjustmentType(JsonField.of(adjustmentType))
+
+                    fun adjustmentType(adjustmentType: JsonField<AdjustmentType>) = apply {
                         this.adjustmentType = adjustmentType
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
-                    fun appliesToPriceIds(appliesToPriceIds: List<String>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds.toMutableList()
+                    fun appliesToPriceIds(appliesToPriceIds: List<String>) =
+                        appliesToPriceIds(JsonField.of(appliesToPriceIds))
+
+                    /** The set of price IDs to which this adjustment applies. */
+                    fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
                     }
 
                     /** The set of price IDs to which this adjustment applies. */
                     fun addAppliesToPriceId(appliesToPriceId: String) = apply {
                         appliesToPriceIds =
-                            (appliesToPriceIds ?: mutableListOf()).apply { add(appliesToPriceId) }
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
-                    fun maximumAmount(maximumAmount: String) = apply {
-                        this.maximumAmount = maximumAmount
-                    }
+                    fun maximumAmount(maximumAmount: String) =
+                        maximumAmount(JsonField.of(maximumAmount))
 
-                    /**
-                     * When false, this adjustment will be applied to a single price. Otherwise, it
-                     * will be applied at the invoice level, possibly to multiple prices.
-                     */
-                    fun isInvoiceLevel(isInvoiceLevel: Boolean?) = apply {
-                        this.isInvoiceLevel = isInvoiceLevel
+                    fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                        this.maximumAmount = maximumAmount
                     }
 
                     /**
@@ -25476,15 +33960,15 @@ constructor(
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
                     fun isInvoiceLevel(isInvoiceLevel: Boolean) =
-                        isInvoiceLevel(isInvoiceLevel as Boolean?)
+                        isInvoiceLevel(JsonField.of(isInvoiceLevel))
 
                     /**
                      * When false, this adjustment will be applied to a single price. Otherwise, it
                      * will be applied at the invoice level, possibly to multiple prices.
                      */
-                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-                    fun isInvoiceLevel(isInvoiceLevel: Optional<Boolean>) =
-                        isInvoiceLevel(isInvoiceLevel.orElse(null) as Boolean?)
+                    fun isInvoiceLevel(isInvoiceLevel: JsonField<Boolean>) = apply {
+                        this.isInvoiceLevel = isInvoiceLevel
+                    }
 
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
@@ -25516,7 +34000,7 @@ constructor(
                             checkNotNull(appliesToPriceIds) {
                                     "`appliesToPriceIds` is required but was not set"
                                 }
-                                .toImmutable(),
+                                .map { it.toImmutable() },
                             checkNotNull(maximumAmount) {
                                 "`maximumAmount` is required but was not set"
                             },
@@ -25618,60 +34102,137 @@ constructor(
     class ReplacePrice
     @JsonCreator
     private constructor(
-        @JsonProperty("replaces_price_id") private val replacesPriceId: String,
-        @JsonProperty("discounts") private val discounts: List<Discount>?,
-        @JsonProperty("external_price_id") private val externalPriceId: String?,
-        @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-        @JsonProperty("minimum_amount") private val minimumAmount: String?,
-        @JsonProperty("price") private val price: Price?,
-        @JsonProperty("price_id") private val priceId: String?,
+        @JsonProperty("replaces_price_id")
+        @ExcludeMissing
+        private val replacesPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("discounts")
+        @ExcludeMissing
+        private val discounts: JsonField<List<Discount>> = JsonMissing.of(),
+        @JsonProperty("external_price_id")
+        @ExcludeMissing
+        private val externalPriceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("fixed_price_quantity")
+        @ExcludeMissing
+        private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("price")
+        @ExcludeMissing
+        private val price: JsonField<Price> = JsonMissing.of(),
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** The id of the price on the plan to replace in the subscription. */
-        @JsonProperty("replaces_price_id") fun replacesPriceId(): String = replacesPriceId
+        fun replacesPriceId(): String = replacesPriceId.getRequired("replaces_price_id")
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
+         * replacement price.
+         */
+        fun discounts(): Optional<List<Discount>> =
+            Optional.ofNullable(discounts.getNullable("discounts"))
+
+        /** The external price id of the price to add to the subscription. */
+        fun externalPriceId(): Optional<String> =
+            Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+        /** The new quantity of the price, if the price is a fixed price. */
+        fun fixedPriceQuantity(): Optional<Double> =
+            Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
+         * replacement price.
+         */
+        fun maximumAmount(): Optional<String> =
+            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+        /**
+         * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
+         * replacement price.
+         */
+        fun minimumAmount(): Optional<String> =
+            Optional.ofNullable(minimumAmount.getNullable("minimum_amount"))
+
+        /** The definition of a new price to create and add to the subscription. */
+        fun price(): Optional<Price> = Optional.ofNullable(price.getNullable("price"))
+
+        /** The id of the price to add to the subscription. */
+        fun priceId(): Optional<String> = Optional.ofNullable(priceId.getNullable("price_id"))
+
+        /** The id of the price on the plan to replace in the subscription. */
+        @JsonProperty("replaces_price_id")
+        @ExcludeMissing
+        fun _replacesPriceId(): JsonField<String> = replacesPriceId
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
          * replacement price.
          */
         @JsonProperty("discounts")
-        fun discounts(): Optional<List<Discount>> = Optional.ofNullable(discounts)
+        @ExcludeMissing
+        fun _discounts(): JsonField<List<Discount>> = discounts
 
         /** The external price id of the price to add to the subscription. */
         @JsonProperty("external_price_id")
-        fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+        @ExcludeMissing
+        fun _externalPriceId(): JsonField<String> = externalPriceId
 
         /** The new quantity of the price, if the price is a fixed price. */
         @JsonProperty("fixed_price_quantity")
-        fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+        @ExcludeMissing
+        fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
          * replacement price.
          */
         @JsonProperty("maximum_amount")
-        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /**
          * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
          * replacement price.
          */
         @JsonProperty("minimum_amount")
-        fun minimumAmount(): Optional<String> = Optional.ofNullable(minimumAmount)
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The definition of a new price to create and add to the subscription. */
-        @JsonProperty("price") fun price(): Optional<Price> = Optional.ofNullable(price)
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /** The id of the price to add to the subscription. */
-        @JsonProperty("price_id") fun priceId(): Optional<String> = Optional.ofNullable(priceId)
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): ReplacePrice = apply {
+            if (!validated) {
+                replacesPriceId()
+                discounts().map { it.forEach { it.validate() } }
+                externalPriceId()
+                fixedPriceQuantity()
+                maximumAmount()
+                minimumAmount()
+                price()
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -25681,20 +34242,20 @@ constructor(
 
         class Builder {
 
-            private var replacesPriceId: String? = null
-            private var discounts: MutableList<Discount>? = null
-            private var externalPriceId: String? = null
-            private var fixedPriceQuantity: Double? = null
-            private var maximumAmount: String? = null
-            private var minimumAmount: String? = null
-            private var price: Price? = null
-            private var priceId: String? = null
+            private var replacesPriceId: JsonField<String>? = null
+            private var discounts: JsonField<MutableList<Discount>>? = null
+            private var externalPriceId: JsonField<String> = JsonMissing.of()
+            private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+            private var maximumAmount: JsonField<String> = JsonMissing.of()
+            private var minimumAmount: JsonField<String> = JsonMissing.of()
+            private var price: JsonField<Price> = JsonMissing.of()
+            private var priceId: JsonField<String> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(replacePrice: ReplacePrice) = apply {
                 replacesPriceId = replacePrice.replacesPriceId
-                discounts = replacePrice.discounts?.toMutableList()
+                discounts = replacePrice.discounts.map { it.toMutableList() }
                 externalPriceId = replacePrice.externalPriceId
                 fixedPriceQuantity = replacePrice.fixedPriceQuantity
                 maximumAmount = replacePrice.maximumAmount
@@ -25705,7 +34266,11 @@ constructor(
             }
 
             /** The id of the price on the plan to replace in the subscription. */
-            fun replacesPriceId(replacesPriceId: String) = apply {
+            fun replacesPriceId(replacesPriceId: String) =
+                replacesPriceId(JsonField.of(replacesPriceId))
+
+            /** The id of the price on the plan to replace in the subscription. */
+            fun replacesPriceId(replacesPriceId: JsonField<String>) = apply {
                 this.replacesPriceId = replacesPriceId
             }
 
@@ -25713,9 +34278,7 @@ constructor(
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
              * replacement price.
              */
-            fun discounts(discounts: List<Discount>?) = apply {
-                this.discounts = discounts?.toMutableList()
-            }
+            fun discounts(discounts: List<Discount>?) = discounts(JsonField.ofNullable(discounts))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
@@ -25723,28 +34286,48 @@ constructor(
              */
             fun discounts(discounts: Optional<List<Discount>>) = discounts(discounts.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
+             * replacement price.
+             */
+            fun discounts(discounts: JsonField<List<Discount>>) = apply {
+                this.discounts = discounts.map { it.toMutableList() }
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's discounts for the
              * replacement price.
              */
             fun addDiscount(discount: Discount) = apply {
-                discounts = (discounts ?: mutableListOf()).apply { add(discount) }
+                discounts =
+                    (discounts ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(discount)
+                    }
             }
 
             /** The external price id of the price to add to the subscription. */
-            fun externalPriceId(externalPriceId: String?) = apply {
-                this.externalPriceId = externalPriceId
-            }
+            fun externalPriceId(externalPriceId: String?) =
+                externalPriceId(JsonField.ofNullable(externalPriceId))
 
             /** The external price id of the price to add to the subscription. */
             fun externalPriceId(externalPriceId: Optional<String>) =
                 externalPriceId(externalPriceId.orElse(null))
 
-            /** The new quantity of the price, if the price is a fixed price. */
-            fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                this.fixedPriceQuantity = fixedPriceQuantity
+            /** The external price id of the price to add to the subscription. */
+            fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                this.externalPriceId = externalPriceId
             }
 
+            /** The new quantity of the price, if the price is a fixed price. */
+            fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
+
             /** The new quantity of the price, if the price is a fixed price. */
             fun fixedPriceQuantity(fixedPriceQuantity: Double) =
                 fixedPriceQuantity(fixedPriceQuantity as Double?)
@@ -25754,11 +34337,17 @@ constructor(
             fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                 fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
+            /** The new quantity of the price, if the price is a fixed price. */
+            fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                this.fixedPriceQuantity = fixedPriceQuantity
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
              * replacement price.
              */
-            fun maximumAmount(maximumAmount: String?) = apply { this.maximumAmount = maximumAmount }
+            fun maximumAmount(maximumAmount: String?) =
+                maximumAmount(JsonField.ofNullable(maximumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
@@ -25767,11 +34356,20 @@ constructor(
             fun maximumAmount(maximumAmount: Optional<String>) =
                 maximumAmount(maximumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's maximum amount for the
+             * replacement price.
+             */
+            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                this.maximumAmount = maximumAmount
+            }
+
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
              * replacement price.
              */
-            fun minimumAmount(minimumAmount: String?) = apply { this.minimumAmount = minimumAmount }
+            fun minimumAmount(minimumAmount: String?) =
+                minimumAmount(JsonField.ofNullable(minimumAmount))
 
             /**
              * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
@@ -25780,138 +34378,141 @@ constructor(
             fun minimumAmount(minimumAmount: Optional<String>) =
                 minimumAmount(minimumAmount.orElse(null))
 
+            /**
+             * [DEPRECATED] Use add_adjustments instead. The subscription's minimum amount for the
+             * replacement price.
+             */
+            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
+                this.minimumAmount = minimumAmount
+            }
+
             /** The definition of a new price to create and add to the subscription. */
-            fun price(price: Price?) = apply { this.price = price }
+            fun price(price: Price?) = price(JsonField.ofNullable(price))
 
             /** The definition of a new price to create and add to the subscription. */
             fun price(price: Optional<Price>) = price(price.orElse(null))
 
-            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) = apply {
-                this.price = Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice)
-            }
+            /** The definition of a new price to create and add to the subscription. */
+            fun price(price: JsonField<Price>) = apply { this.price = price }
 
-            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) = apply {
-                this.price = Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice)
-            }
+            fun price(newSubscriptionUnitPrice: Price.NewSubscriptionUnitPrice) =
+                price(Price.ofNewSubscriptionUnitPrice(newSubscriptionUnitPrice))
 
-            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) = apply {
-                this.price = Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice)
-            }
+            fun price(newSubscriptionPackagePrice: Price.NewSubscriptionPackagePrice) =
+                price(Price.ofNewSubscriptionPackagePrice(newSubscriptionPackagePrice))
 
-            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice)
-            }
+            fun price(newSubscriptionMatrixPrice: Price.NewSubscriptionMatrixPrice) =
+                price(Price.ofNewSubscriptionMatrixPrice(newSubscriptionMatrixPrice))
 
-            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice)
-            }
+            fun price(newSubscriptionTieredPrice: Price.NewSubscriptionTieredPrice) =
+                price(Price.ofNewSubscriptionTieredPrice(newSubscriptionTieredPrice))
 
-            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice)
-            }
+            fun price(newSubscriptionTieredBpsPrice: Price.NewSubscriptionTieredBpsPrice) =
+                price(Price.ofNewSubscriptionTieredBpsPrice(newSubscriptionTieredBpsPrice))
 
-            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice)
-            }
+            fun price(newSubscriptionBpsPrice: Price.NewSubscriptionBpsPrice) =
+                price(Price.ofNewSubscriptionBpsPrice(newSubscriptionBpsPrice))
 
-            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) = apply {
-                this.price = Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice)
-            }
+            fun price(newSubscriptionBulkBpsPrice: Price.NewSubscriptionBulkBpsPrice) =
+                price(Price.ofNewSubscriptionBulkBpsPrice(newSubscriptionBulkBpsPrice))
+
+            fun price(newSubscriptionBulkPrice: Price.NewSubscriptionBulkPrice) =
+                price(Price.ofNewSubscriptionBulkPrice(newSubscriptionBulkPrice))
 
             fun price(
                 newSubscriptionThresholdTotalAmountPrice:
                     Price.NewSubscriptionThresholdTotalAmountPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionThresholdTotalAmountPrice(
                         newSubscriptionThresholdTotalAmountPrice
                     )
-            }
+                )
 
             fun price(newSubscriptionTieredPackagePrice: Price.NewSubscriptionTieredPackagePrice) =
-                apply {
-                    this.price =
-                        Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice)
-                }
+                price(Price.ofNewSubscriptionTieredPackagePrice(newSubscriptionTieredPackagePrice))
 
             fun price(
                 newSubscriptionTieredWithMinimumPrice: Price.NewSubscriptionTieredWithMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTieredWithMinimumPrice(
                         newSubscriptionTieredWithMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithPercentPrice: Price.NewSubscriptionUnitWithPercentPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithPercentPrice(newSubscriptionUnitWithPercentPrice)
-            }
+                )
 
             fun price(
                 newSubscriptionPackageWithAllocationPrice:
                     Price.NewSubscriptionPackageWithAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionPackageWithAllocationPrice(
                         newSubscriptionPackageWithAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionTierWithProrationPrice: Price.NewSubscriptionTierWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionTierWithProrationPrice(
                         newSubscriptionTierWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionUnitWithProrationPrice: Price.NewSubscriptionUnitWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionUnitWithProrationPrice(
                         newSubscriptionUnitWithProrationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedAllocationPrice: Price.NewSubscriptionGroupedAllocationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedAllocationPrice(
                         newSubscriptionGroupedAllocationPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionGroupedWithProratedMinimumPrice:
                     Price.NewSubscriptionGroupedWithProratedMinimumPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionGroupedWithProratedMinimumPrice(
                         newSubscriptionGroupedWithProratedMinimumPrice
                     )
-            }
+                )
 
             fun price(
                 newSubscriptionBulkWithProrationPrice: Price.NewSubscriptionBulkWithProrationPrice
-            ) = apply {
-                this.price =
+            ) =
+                price(
                     Price.ofNewSubscriptionBulkWithProrationPrice(
                         newSubscriptionBulkWithProrationPrice
                     )
-            }
+                )
 
             /** The id of the price to add to the subscription. */
-            fun priceId(priceId: String?) = apply { this.priceId = priceId }
+            fun priceId(priceId: String?) = priceId(JsonField.ofNullable(priceId))
 
             /** The id of the price to add to the subscription. */
             fun priceId(priceId: Optional<String>) = priceId(priceId.orElse(null))
 
+            /** The id of the price to add to the subscription. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -25936,7 +34537,7 @@ constructor(
                     checkNotNull(replacesPriceId) {
                         "`replacesPriceId` is required but was not set"
                     },
-                    discounts?.toImmutable(),
+                    (discounts ?: JsonMissing.of()).map { it.toImmutable() },
                     externalPriceId,
                     fixedPriceQuantity,
                     maximumAmount,
@@ -25951,37 +34552,81 @@ constructor(
         class Discount
         @JsonCreator
         private constructor(
-            @JsonProperty("discount_type") private val discountType: DiscountType,
-            @JsonProperty("amount_discount") private val amountDiscount: String?,
-            @JsonProperty("percentage_discount") private val percentageDiscount: Double?,
-            @JsonProperty("usage_discount") private val usageDiscount: Double?,
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            private val discountType: JsonField<DiscountType> = JsonMissing.of(),
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            private val amountDiscount: JsonField<String> = JsonMissing.of(),
+            @JsonProperty("percentage_discount")
+            @ExcludeMissing
+            private val percentageDiscount: JsonField<Double> = JsonMissing.of(),
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            private val usageDiscount: JsonField<Double> = JsonMissing.of(),
             @JsonAnySetter
             private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
         ) {
 
-            @JsonProperty("discount_type") fun discountType(): DiscountType = discountType
+            fun discountType(): DiscountType = discountType.getRequired("discount_type")
+
+            /** Only available if discount_type is `amount`. */
+            fun amountDiscount(): Optional<String> =
+                Optional.ofNullable(amountDiscount.getNullable("amount_discount"))
+
+            /**
+             * Only available if discount_type is `percentage`. This is a number between 0 and 1.
+             */
+            fun percentageDiscount(): Optional<Double> =
+                Optional.ofNullable(percentageDiscount.getNullable("percentage_discount"))
+
+            /**
+             * Only available if discount_type is `usage`. Number of usage units that this discount
+             * is for
+             */
+            fun usageDiscount(): Optional<Double> =
+                Optional.ofNullable(usageDiscount.getNullable("usage_discount"))
+
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** Only available if discount_type is `amount`. */
             @JsonProperty("amount_discount")
-            fun amountDiscount(): Optional<String> = Optional.ofNullable(amountDiscount)
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /**
              * Only available if discount_type is `percentage`. This is a number between 0 and 1.
              */
             @JsonProperty("percentage_discount")
-            fun percentageDiscount(): Optional<Double> = Optional.ofNullable(percentageDiscount)
+            @ExcludeMissing
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
             @JsonProperty("usage_discount")
-            fun usageDiscount(): Optional<Double> = Optional.ofNullable(usageDiscount)
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
             fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+            private var validated: Boolean = false
+
+            fun validate(): Discount = apply {
+                if (!validated) {
+                    discountType()
+                    amountDiscount()
+                    percentageDiscount()
+                    usageDiscount()
+                    validated = true
+                }
+            }
+
             fun toBuilder() = Builder().from(this)
 
             companion object {
@@ -25991,10 +34636,10 @@ constructor(
 
             class Builder {
 
-                private var discountType: DiscountType? = null
-                private var amountDiscount: String? = null
-                private var percentageDiscount: Double? = null
-                private var usageDiscount: Double? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var amountDiscount: JsonField<String> = JsonMissing.of()
+                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
+                private var usageDiscount: JsonField<Double> = JsonMissing.of()
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -26006,26 +34651,32 @@ constructor(
                     additionalProperties = discount.additionalProperties.toMutableMap()
                 }
 
-                fun discountType(discountType: DiscountType) = apply {
+                fun discountType(discountType: DiscountType) =
+                    discountType(JsonField.of(discountType))
+
+                fun discountType(discountType: JsonField<DiscountType>) = apply {
                     this.discountType = discountType
                 }
 
                 /** Only available if discount_type is `amount`. */
-                fun amountDiscount(amountDiscount: String?) = apply {
-                    this.amountDiscount = amountDiscount
-                }
+                fun amountDiscount(amountDiscount: String?) =
+                    amountDiscount(JsonField.ofNullable(amountDiscount))
 
                 /** Only available if discount_type is `amount`. */
                 fun amountDiscount(amountDiscount: Optional<String>) =
                     amountDiscount(amountDiscount.orElse(null))
 
+                /** Only available if discount_type is `amount`. */
+                fun amountDiscount(amountDiscount: JsonField<String>) = apply {
+                    this.amountDiscount = amountDiscount
+                }
+
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
                  * and 1.
                  */
-                fun percentageDiscount(percentageDiscount: Double?) = apply {
-                    this.percentageDiscount = percentageDiscount
-                }
+                fun percentageDiscount(percentageDiscount: Double?) =
+                    percentageDiscount(JsonField.ofNullable(percentageDiscount))
 
                 /**
                  * Only available if discount_type is `percentage`. This is a number between 0
@@ -26042,13 +34693,20 @@ constructor(
                 fun percentageDiscount(percentageDiscount: Optional<Double>) =
                     percentageDiscount(percentageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `percentage`. This is a number between 0
+                 * and 1.
+                 */
+                fun percentageDiscount(percentageDiscount: JsonField<Double>) = apply {
+                    this.percentageDiscount = percentageDiscount
+                }
+
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
                  * discount is for
                  */
-                fun usageDiscount(usageDiscount: Double?) = apply {
-                    this.usageDiscount = usageDiscount
-                }
+                fun usageDiscount(usageDiscount: Double?) =
+                    usageDiscount(JsonField.ofNullable(usageDiscount))
 
                 /**
                  * Only available if discount_type is `usage`. Number of usage units that this
@@ -26064,6 +34722,14 @@ constructor(
                 fun usageDiscount(usageDiscount: Optional<Double>) =
                     usageDiscount(usageDiscount.orElse(null) as Double?)
 
+                /**
+                 * Only available if discount_type is `usage`. Number of usage units that this
+                 * discount is for
+                 */
+                fun usageDiscount(usageDiscount: JsonField<Double>) = apply {
+                    this.usageDiscount = usageDiscount
+                }
+
                 fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                     this.additionalProperties.clear()
                     putAllAdditionalProperties(additionalProperties)
@@ -26221,6 +34887,8 @@ constructor(
             private val _json: JsonValue? = null,
         ) {
 
+            private var validated: Boolean = false
+
             fun newSubscriptionUnitPrice(): Optional<NewSubscriptionUnitPrice> =
                 Optional.ofNullable(newSubscriptionUnitPrice)
 
@@ -26469,6 +35137,52 @@ constructor(
                 }
             }
 
+            fun validate(): Price = apply {
+                if (!validated) {
+                    if (
+                        newSubscriptionUnitPrice == null &&
+                            newSubscriptionPackagePrice == null &&
+                            newSubscriptionMatrixPrice == null &&
+                            newSubscriptionTieredPrice == null &&
+                            newSubscriptionTieredBpsPrice == null &&
+                            newSubscriptionBpsPrice == null &&
+                            newSubscriptionBulkBpsPrice == null &&
+                            newSubscriptionBulkPrice == null &&
+                            newSubscriptionThresholdTotalAmountPrice == null &&
+                            newSubscriptionTieredPackagePrice == null &&
+                            newSubscriptionTieredWithMinimumPrice == null &&
+                            newSubscriptionUnitWithPercentPrice == null &&
+                            newSubscriptionPackageWithAllocationPrice == null &&
+                            newSubscriptionTierWithProrationPrice == null &&
+                            newSubscriptionUnitWithProrationPrice == null &&
+                            newSubscriptionGroupedAllocationPrice == null &&
+                            newSubscriptionGroupedWithProratedMinimumPrice == null &&
+                            newSubscriptionBulkWithProrationPrice == null
+                    ) {
+                        throw OrbInvalidDataException("Unknown Price: $_json")
+                    }
+                    newSubscriptionUnitPrice?.validate()
+                    newSubscriptionPackagePrice?.validate()
+                    newSubscriptionMatrixPrice?.validate()
+                    newSubscriptionTieredPrice?.validate()
+                    newSubscriptionTieredBpsPrice?.validate()
+                    newSubscriptionBpsPrice?.validate()
+                    newSubscriptionBulkBpsPrice?.validate()
+                    newSubscriptionBulkPrice?.validate()
+                    newSubscriptionThresholdTotalAmountPrice?.validate()
+                    newSubscriptionTieredPackagePrice?.validate()
+                    newSubscriptionTieredWithMinimumPrice?.validate()
+                    newSubscriptionUnitWithPercentPrice?.validate()
+                    newSubscriptionPackageWithAllocationPrice?.validate()
+                    newSubscriptionTierWithProrationPrice?.validate()
+                    newSubscriptionUnitWithProrationPrice?.validate()
+                    newSubscriptionGroupedAllocationPrice?.validate()
+                    newSubscriptionGroupedWithProratedMinimumPrice?.validate()
+                    newSubscriptionBulkWithProrationPrice?.validate()
+                    validated = true
+                }
+            }
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) {
                     return true
@@ -26737,55 +35451,76 @@ constructor(
 
                     when (modelType) {
                         "unit" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>())?.let {
-                                return Price(newSubscriptionUnitPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionUnitPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionUnitPrice = it, _json = json)
+                                }
                         }
                         "package" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionPackagePrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionPackagePrice = it, _json = json)
                                 }
                         }
                         "matrix" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionMatrixPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionMatrixPrice = it, _json = json)
                                 }
                         }
                         "tiered" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredPrice = it, _json = json)
                                 }
                         }
                         "tiered_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionTieredBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionTieredBpsPrice = it, _json = json)
                                 }
                         }
                         "bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>())?.let {
-                                return Price(newSubscriptionBpsPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBpsPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBpsPrice = it, _json = json)
+                                }
                         }
                         "bulk_bps" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>())
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkBpsPrice>()) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(newSubscriptionBulkBpsPrice = it, _json = json)
                                 }
                         }
                         "bulk" -> {
-                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>())?.let {
-                                return Price(newSubscriptionBulkPrice = it, _json = json)
-                            }
+                            tryDeserialize(node, jacksonTypeRef<NewSubscriptionBulkPrice>()) {
+                                    it.validate()
+                                }
+                                ?.let {
+                                    return Price(newSubscriptionBulkPrice = it, _json = json)
+                                }
                         }
                         "threshold_total_amount" -> {
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionThresholdTotalAmountPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionThresholdTotalAmountPrice = it,
@@ -26797,7 +35532,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredPackagePrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredPackagePrice = it,
@@ -26809,7 +35546,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTieredWithMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTieredWithMinimumPrice = it,
@@ -26821,7 +35560,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithPercentPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithPercentPrice = it,
@@ -26833,7 +35574,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionPackageWithAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionPackageWithAllocationPrice = it,
@@ -26845,7 +35588,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionTierWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionTierWithProrationPrice = it,
@@ -26857,7 +35602,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionUnitWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionUnitWithProrationPrice = it,
@@ -26869,7 +35616,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedAllocationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedAllocationPrice = it,
@@ -26881,7 +35630,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionGroupedWithProratedMinimumPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionGroupedWithProratedMinimumPrice = it,
@@ -26893,7 +35644,9 @@ constructor(
                             tryDeserialize(
                                     node,
                                     jacksonTypeRef<NewSubscriptionBulkWithProrationPrice>()
-                                )
+                                ) {
+                                    it.validate()
+                                }
                                 ?.let {
                                     return Price(
                                         newSubscriptionBulkWithProrationPrice = it,
@@ -26963,96 +35716,229 @@ constructor(
             class NewSubscriptionUnitPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("unit_config") private val unitConfig: UnitConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                private val unitConfig: JsonField<UnitConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("unit_config") fun unitConfig(): UnitConfig = unitConfig
+                fun unitConfig(): UnitConfig = unitConfig.getRequired("unit_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("unit_config")
+                @ExcludeMissing
+                fun _unitConfig(): JsonField<UnitConfig> = unitConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -27060,19 +35946,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -27082,22 +35994,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitConfig: UnitConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitConfig: JsonField<UnitConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -27125,25 +36040,41 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
-                    fun unitConfig(unitConfig: UnitConfig) = apply { this.unitConfig = unitConfig }
+                    fun unitConfig(unitConfig: UnitConfig) = unitConfig(JsonField.of(unitConfig))
+
+                    fun unitConfig(unitConfig: JsonField<UnitConfig>) = apply {
+                        this.unitConfig = unitConfig
+                    }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -27152,13 +36083,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -27175,13 +36113,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -27191,12 +36137,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -27211,11 +36164,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -27223,22 +36183,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -27255,22 +36224,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -27280,12 +36264,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -27294,11 +36286,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -27307,6 +36307,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -27489,18 +36497,34 @@ constructor(
                 class UnitConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("unit_amount") private val unitAmount: String,
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    private val unitAmount: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Rate per unit of usage */
-                    @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                    fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                    /** Rate per unit of usage */
+                    @JsonProperty("unit_amount")
+                    @ExcludeMissing
+                    fun _unitAmount(): JsonField<String> = unitAmount
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitConfig = apply {
+                        if (!validated) {
+                            unitAmount()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27510,7 +36534,7 @@ constructor(
 
                     class Builder {
 
-                        private var unitAmount: String? = null
+                        private var unitAmount: JsonField<String>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27521,7 +36545,12 @@ constructor(
                         }
 
                         /** Rate per unit of usage */
-                        fun unitAmount(unitAmount: String) = apply { this.unitAmount = unitAmount }
+                        fun unitAmount(unitAmount: String) = unitAmount(JsonField.of(unitAmount))
+
+                        /** Rate per unit of usage */
+                        fun unitAmount(unitAmount: JsonField<String>) = apply {
+                            this.unitAmount = unitAmount
+                        }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
@@ -27580,22 +36609,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27605,8 +36658,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27620,10 +36673,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27744,22 +36804,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27769,8 +36853,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -27785,10 +36869,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -27918,6 +37009,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -27999,96 +37098,229 @@ constructor(
             class NewSubscriptionPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("package_config") private val packageConfig: PackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                private val packageConfig: JsonField<PackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun packageConfig(): PackageConfig = packageConfig.getRequired("package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
-                @JsonProperty("package_config") fun packageConfig(): PackageConfig = packageConfig
+                @JsonProperty("package_config")
+                @ExcludeMissing
+                fun _packageConfig(): JsonField<PackageConfig> = packageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -28096,19 +37328,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -28118,22 +37376,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageConfig: PackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageConfig: JsonField<PackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -28162,17 +37423,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun packageConfig(packageConfig: PackageConfig) =
+                        packageConfig(JsonField.of(packageConfig))
 
-                    fun packageConfig(packageConfig: PackageConfig) = apply {
+                    fun packageConfig(packageConfig: JsonField<PackageConfig>) = apply {
                         this.packageConfig = packageConfig
                     }
 
@@ -28180,9 +37457,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -28191,13 +37467,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -28214,13 +37497,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -28230,12 +37521,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -28250,11 +37548,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -28262,22 +37567,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -28294,22 +37608,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -28319,12 +37648,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -28333,11 +37670,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -28346,6 +37691,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -28530,25 +37883,52 @@ constructor(
                 class PackageConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("package_amount") private val packageAmount: String,
-                    @JsonProperty("package_size") private val packageSize: Long,
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    private val packageAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    private val packageSize: JsonField<Long> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** A currency amount to rate usage by */
-                    @JsonProperty("package_amount") fun packageAmount(): String = packageAmount
+                    fun packageAmount(): String = packageAmount.getRequired("package_amount")
+
+                    /**
+                     * An integer amount to represent package size. For example, 1000 here would
+                     * divide usage by 1000 before multiplying by package_amount in rating
+                     */
+                    fun packageSize(): Long = packageSize.getRequired("package_size")
+
+                    /** A currency amount to rate usage by */
+                    @JsonProperty("package_amount")
+                    @ExcludeMissing
+                    fun _packageAmount(): JsonField<String> = packageAmount
 
                     /**
                      * An integer amount to represent package size. For example, 1000 here would
                      * divide usage by 1000 before multiplying by package_amount in rating
                      */
-                    @JsonProperty("package_size") fun packageSize(): Long = packageSize
+                    @JsonProperty("package_size")
+                    @ExcludeMissing
+                    fun _packageSize(): JsonField<Long> = packageSize
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageConfig = apply {
+                        if (!validated) {
+                            packageAmount()
+                            packageSize()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28558,8 +37938,8 @@ constructor(
 
                     class Builder {
 
-                        private var packageAmount: String? = null
-                        private var packageSize: Long? = null
+                        private var packageAmount: JsonField<String>? = null
+                        private var packageSize: JsonField<Long>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28571,7 +37951,11 @@ constructor(
                         }
 
                         /** A currency amount to rate usage by */
-                        fun packageAmount(packageAmount: String) = apply {
+                        fun packageAmount(packageAmount: String) =
+                            packageAmount(JsonField.of(packageAmount))
+
+                        /** A currency amount to rate usage by */
+                        fun packageAmount(packageAmount: JsonField<String>) = apply {
                             this.packageAmount = packageAmount
                         }
 
@@ -28579,7 +37963,13 @@ constructor(
                          * An integer amount to represent package size. For example, 1000 here would
                          * divide usage by 1000 before multiplying by package_amount in rating
                          */
-                        fun packageSize(packageSize: Long) = apply {
+                        fun packageSize(packageSize: Long) = packageSize(JsonField.of(packageSize))
+
+                        /**
+                         * An integer amount to represent package size. For example, 1000 here would
+                         * divide usage by 1000 before multiplying by package_amount in rating
+                         */
+                        fun packageSize(packageSize: JsonField<Long>) = apply {
                             this.packageSize = packageSize
                         }
 
@@ -28643,22 +38033,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28668,8 +38082,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28683,10 +38097,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -28807,22 +38228,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -28832,8 +38277,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -28848,10 +38293,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -28981,6 +38433,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29062,96 +38522,229 @@ constructor(
             class NewSubscriptionMatrixPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("matrix_config") private val matrixConfig: MatrixConfig,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                private val matrixConfig: JsonField<MatrixConfig> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun matrixConfig(): MatrixConfig = matrixConfig.getRequired("matrix_config")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("matrix_config") fun matrixConfig(): MatrixConfig = matrixConfig
+                @JsonProperty("matrix_config")
+                @ExcludeMissing
+                fun _matrixConfig(): JsonField<MatrixConfig> = matrixConfig
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -29159,19 +38752,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionMatrixPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        matrixConfig().validate()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -29181,22 +38800,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var matrixConfig: MatrixConfig? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var matrixConfig: JsonField<MatrixConfig>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -29225,27 +38847,42 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun matrixConfig(matrixConfig: MatrixConfig) =
+                        matrixConfig(JsonField.of(matrixConfig))
 
-                    fun matrixConfig(matrixConfig: MatrixConfig) = apply {
+                    fun matrixConfig(matrixConfig: JsonField<MatrixConfig>) = apply {
                         this.matrixConfig = matrixConfig
                     }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -29254,13 +38891,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -29277,13 +38921,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -29293,12 +38945,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -29313,11 +38972,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -29325,22 +38991,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -29357,22 +39032,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -29382,12 +39072,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -29396,11 +39094,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -29409,6 +39115,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -29541,31 +39255,66 @@ constructor(
                 class MatrixConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("default_unit_amount") private val defaultUnitAmount: String,
-                    @JsonProperty("dimensions") private val dimensions: List<String?>,
-                    @JsonProperty("matrix_values") private val matrixValues: List<MatrixValue>,
+                    @JsonProperty("default_unit_amount")
+                    @ExcludeMissing
+                    private val defaultUnitAmount: JsonField<String> = JsonMissing.of(),
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    private val dimensions: JsonField<List<String?>> = JsonMissing.of(),
+                    @JsonProperty("matrix_values")
+                    @ExcludeMissing
+                    private val matrixValues: JsonField<List<MatrixValue>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
+                    /**
+                     * Default per unit rate for any usage not bucketed into a specified
+                     * matrix_value
+                     */
+                    fun defaultUnitAmount(): String =
+                        defaultUnitAmount.getRequired("default_unit_amount")
+
+                    /** One or two event property values to evaluate matrix groups by */
+                    fun dimensions(): List<String?> = dimensions.getRequired("dimensions")
+
+                    /** Matrix values for specified matrix grouping keys */
+                    fun matrixValues(): List<MatrixValue> =
+                        matrixValues.getRequired("matrix_values")
+
                     /**
                      * Default per unit rate for any usage not bucketed into a specified
                      * matrix_value
                      */
                     @JsonProperty("default_unit_amount")
-                    fun defaultUnitAmount(): String = defaultUnitAmount
+                    @ExcludeMissing
+                    fun _defaultUnitAmount(): JsonField<String> = defaultUnitAmount
 
                     /** One or two event property values to evaluate matrix groups by */
-                    @JsonProperty("dimensions") fun dimensions(): List<String?> = dimensions
+                    @JsonProperty("dimensions")
+                    @ExcludeMissing
+                    fun _dimensions(): JsonField<List<String?>> = dimensions
 
                     /** Matrix values for specified matrix grouping keys */
                     @JsonProperty("matrix_values")
-                    fun matrixValues(): List<MatrixValue> = matrixValues
+                    @ExcludeMissing
+                    fun _matrixValues(): JsonField<List<MatrixValue>> = matrixValues
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): MatrixConfig = apply {
+                        if (!validated) {
+                            defaultUnitAmount()
+                            dimensions()
+                            matrixValues().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29575,17 +39324,17 @@ constructor(
 
                     class Builder {
 
-                        private var defaultUnitAmount: String? = null
-                        private var dimensions: MutableList<String?>? = null
-                        private var matrixValues: MutableList<MatrixValue>? = null
+                        private var defaultUnitAmount: JsonField<String>? = null
+                        private var dimensions: JsonField<MutableList<String?>>? = null
+                        private var matrixValues: JsonField<MutableList<MatrixValue>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(matrixConfig: MatrixConfig) = apply {
                             defaultUnitAmount = matrixConfig.defaultUnitAmount
-                            dimensions = matrixConfig.dimensions.toMutableList()
-                            matrixValues = matrixConfig.matrixValues.toMutableList()
+                            dimensions = matrixConfig.dimensions.map { it.toMutableList() }
+                            matrixValues = matrixConfig.matrixValues.map { it.toMutableList() }
                             additionalProperties = matrixConfig.additionalProperties.toMutableMap()
                         }
 
@@ -29593,29 +39342,61 @@ constructor(
                          * Default per unit rate for any usage not bucketed into a specified
                          * matrix_value
                          */
-                        fun defaultUnitAmount(defaultUnitAmount: String) = apply {
+                        fun defaultUnitAmount(defaultUnitAmount: String) =
+                            defaultUnitAmount(JsonField.of(defaultUnitAmount))
+
+                        /**
+                         * Default per unit rate for any usage not bucketed into a specified
+                         * matrix_value
+                         */
+                        fun defaultUnitAmount(defaultUnitAmount: JsonField<String>) = apply {
                             this.defaultUnitAmount = defaultUnitAmount
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
-                        fun dimensions(dimensions: List<String?>) = apply {
-                            this.dimensions = dimensions.toMutableList()
+                        fun dimensions(dimensions: List<String?>) =
+                            dimensions(JsonField.of(dimensions))
+
+                        /** One or two event property values to evaluate matrix groups by */
+                        fun dimensions(dimensions: JsonField<List<String?>>) = apply {
+                            this.dimensions = dimensions.map { it.toMutableList() }
                         }
 
                         /** One or two event property values to evaluate matrix groups by */
                         fun addDimension(dimension: String) = apply {
-                            dimensions = (dimensions ?: mutableListOf()).apply { add(dimension) }
+                            dimensions =
+                                (dimensions ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(dimension)
+                                }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
-                        fun matrixValues(matrixValues: List<MatrixValue>) = apply {
-                            this.matrixValues = matrixValues.toMutableList()
+                        fun matrixValues(matrixValues: List<MatrixValue>) =
+                            matrixValues(JsonField.of(matrixValues))
+
+                        /** Matrix values for specified matrix grouping keys */
+                        fun matrixValues(matrixValues: JsonField<List<MatrixValue>>) = apply {
+                            this.matrixValues = matrixValues.map { it.toMutableList() }
                         }
 
                         /** Matrix values for specified matrix grouping keys */
                         fun addMatrixValue(matrixValue: MatrixValue) = apply {
                             matrixValues =
-                                (matrixValues ?: mutableListOf()).apply { add(matrixValue) }
+                                (matrixValues ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(matrixValue)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -29648,11 +39429,11 @@ constructor(
                                 checkNotNull(dimensions) {
                                         "`dimensions` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 checkNotNull(matrixValues) {
                                         "`matrixValues` is required but was not set"
                                     }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable(),
                             )
                     }
@@ -29662,28 +39443,55 @@ constructor(
                     @JsonCreator
                     private constructor(
                         @JsonProperty("dimension_values")
-                        private val dimensionValues: List<String?>,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
+                        @ExcludeMissing
+                        private val dimensionValues: JsonField<List<String?>> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
+                        /**
+                         * One or two matrix keys to filter usage to this Matrix value by. For
+                         * example, ["region", "tier"] could be used to filter cloud usage by a
+                         * cloud region and an instance tier.
+                         */
+                        fun dimensionValues(): List<String?> =
+                            dimensionValues.getRequired("dimension_values")
+
+                        /** Unit price for the specified dimension_values */
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
                         /**
                          * One or two matrix keys to filter usage to this Matrix value by. For
                          * example, ["region", "tier"] could be used to filter cloud usage by a
                          * cloud region and an instance tier.
                          */
                         @JsonProperty("dimension_values")
-                        fun dimensionValues(): List<String?> = dimensionValues
+                        @ExcludeMissing
+                        fun _dimensionValues(): JsonField<List<String?>> = dimensionValues
 
                         /** Unit price for the specified dimension_values */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): MatrixValue = apply {
+                            if (!validated) {
+                                dimensionValues()
+                                unitAmount()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -29693,14 +39501,15 @@ constructor(
 
                         class Builder {
 
-                            private var dimensionValues: MutableList<String?>? = null
-                            private var unitAmount: String? = null
+                            private var dimensionValues: JsonField<MutableList<String?>>? = null
+                            private var unitAmount: JsonField<String>? = null
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
                             @JvmSynthetic
                             internal fun from(matrixValue: MatrixValue) = apply {
-                                dimensionValues = matrixValue.dimensionValues.toMutableList()
+                                dimensionValues =
+                                    matrixValue.dimensionValues.map { it.toMutableList() }
                                 unitAmount = matrixValue.unitAmount
                                 additionalProperties =
                                     matrixValue.additionalProperties.toMutableMap()
@@ -29711,8 +39520,16 @@ constructor(
                              * example, ["region", "tier"] could be used to filter cloud usage by a
                              * cloud region and an instance tier.
                              */
-                            fun dimensionValues(dimensionValues: List<String?>) = apply {
-                                this.dimensionValues = dimensionValues.toMutableList()
+                            fun dimensionValues(dimensionValues: List<String?>) =
+                                dimensionValues(JsonField.of(dimensionValues))
+
+                            /**
+                             * One or two matrix keys to filter usage to this Matrix value by. For
+                             * example, ["region", "tier"] could be used to filter cloud usage by a
+                             * cloud region and an instance tier.
+                             */
+                            fun dimensionValues(dimensionValues: JsonField<List<String?>>) = apply {
+                                this.dimensionValues = dimensionValues.map { it.toMutableList() }
                             }
 
                             /**
@@ -29722,13 +39539,23 @@ constructor(
                              */
                             fun addDimensionValue(dimensionValue: String) = apply {
                                 dimensionValues =
-                                    (dimensionValues ?: mutableListOf()).apply {
-                                        add(dimensionValue)
+                                    (dimensionValues ?: JsonField.of(mutableListOf())).apply {
+                                        asKnown()
+                                            .orElseThrow {
+                                                IllegalStateException(
+                                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                                )
+                                            }
+                                            .add(dimensionValue)
                                     }
                             }
 
                             /** Unit price for the specified dimension_values */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Unit price for the specified dimension_values */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -29759,7 +39586,7 @@ constructor(
                                     checkNotNull(dimensionValues) {
                                             "`dimensionValues` is required but was not set"
                                         }
-                                        .toImmutable(),
+                                        .map { it.toImmutable() },
                                     checkNotNull(unitAmount) {
                                         "`unitAmount` is required but was not set"
                                     },
@@ -29863,22 +39690,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -29888,8 +39739,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -29903,10 +39754,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -30027,22 +39885,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30052,8 +39934,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -30068,10 +39950,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -30201,6 +40090,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30282,96 +40179,229 @@ constructor(
             class NewSubscriptionTieredPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_config") private val tieredConfig: TieredConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                private val tieredConfig: JsonField<TieredConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_config") fun tieredConfig(): TieredConfig = tieredConfig
+                fun tieredConfig(): TieredConfig = tieredConfig.getRequired("tiered_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_config")
+                @ExcludeMissing
+                fun _tieredConfig(): JsonField<TieredConfig> = tieredConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -30379,19 +40409,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -30401,22 +40457,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredConfig: TieredConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredConfig: JsonField<TieredConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -30445,17 +40504,33 @@ constructor(
                         }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredConfig(tieredConfig: TieredConfig) =
+                        tieredConfig(JsonField.of(tieredConfig))
 
-                    fun tieredConfig(tieredConfig: TieredConfig) = apply {
+                    fun tieredConfig(tieredConfig: JsonField<TieredConfig>) = apply {
                         this.tieredConfig = tieredConfig
                     }
 
@@ -30463,9 +40538,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -30474,13 +40548,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -30497,13 +40578,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -30513,12 +40602,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -30533,11 +40629,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -30545,22 +40648,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -30577,22 +40689,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -30602,12 +40729,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -30616,11 +40751,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -30629,6 +40772,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -30813,18 +40964,34 @@ constructor(
                 class TieredConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Tiers for rating based on total usage quantities into the specified tier */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Tiers for rating based on total usage quantities into the specified tier */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -30834,26 +41001,42 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredConfig: TieredConfig) = apply {
-                            tiers = tieredConfig.tiers.toMutableList()
+                            tiers = tieredConfig.tiers.map { it.toMutableList() }
                             additionalProperties = tieredConfig.additionalProperties.toMutableMap()
                         }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for rating based on total usage quantities into the specified tier
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for rating based on total usage quantities into the specified tier
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -30881,7 +41064,7 @@ constructor(
                         fun build(): TieredConfig =
                             TieredConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -30890,30 +41073,64 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("first_unit") private val firstUnit: Double,
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("last_unit") private val lastUnit: Double?,
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        private val firstUnit: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("last_unit")
+                        @ExcludeMissing
+                        private val lastUnit: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("first_unit") fun firstUnit(): Double = firstUnit
+                        fun firstUnit(): Double = firstUnit.getRequired("first_unit")
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /**
+                         * Exclusive tier ending value. If null, this is treated as the last tier
+                         */
+                        fun lastUnit(): Optional<Double> =
+                            Optional.ofNullable(lastUnit.getNullable("last_unit"))
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("first_unit")
+                        @ExcludeMissing
+                        fun _firstUnit(): JsonField<Double> = firstUnit
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /**
                          * Exclusive tier ending value. If null, this is treated as the last tier
                          */
                         @JsonProperty("last_unit")
-                        fun lastUnit(): Optional<Double> = Optional.ofNullable(lastUnit)
+                        @ExcludeMissing
+                        fun _lastUnit(): JsonField<Double> = lastUnit
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                firstUnit()
+                                unitAmount()
+                                lastUnit()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -30923,9 +41140,9 @@ constructor(
 
                         class Builder {
 
-                            private var firstUnit: Double? = null
-                            private var unitAmount: String? = null
-                            private var lastUnit: Double? = null
+                            private var firstUnit: JsonField<Double>? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var lastUnit: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -30938,10 +41155,19 @@ constructor(
                             }
 
                             /** Inclusive tier starting value */
-                            fun firstUnit(firstUnit: Double) = apply { this.firstUnit = firstUnit }
+                            fun firstUnit(firstUnit: Double) = firstUnit(JsonField.of(firstUnit))
+
+                            /** Inclusive tier starting value */
+                            fun firstUnit(firstUnit: JsonField<Double>) = apply {
+                                this.firstUnit = firstUnit
+                            }
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
@@ -30949,7 +41175,8 @@ constructor(
                              * Exclusive tier ending value. If null, this is treated as the last
                              * tier
                              */
-                            fun lastUnit(lastUnit: Double?) = apply { this.lastUnit = lastUnit }
+                            fun lastUnit(lastUnit: Double?) =
+                                lastUnit(JsonField.ofNullable(lastUnit))
 
                             /**
                              * Exclusive tier ending value. If null, this is treated as the last
@@ -30967,6 +41194,14 @@ constructor(
                             fun lastUnit(lastUnit: Optional<Double>) =
                                 lastUnit(lastUnit.orElse(null) as Double?)
 
+                            /**
+                             * Exclusive tier ending value. If null, this is treated as the last
+                             * tier
+                             */
+                            fun lastUnit(lastUnit: JsonField<Double>) = apply {
+                                this.lastUnit = lastUnit
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -31046,22 +41281,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31071,8 +41330,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -31086,10 +41345,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -31210,22 +41476,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31235,8 +41525,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -31251,10 +41541,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -31384,6 +41681,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -31465,97 +41770,230 @@ constructor(
             class NewSubscriptionTieredBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("tiered_bps_config") private val tieredBpsConfig: TieredBpsConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("tiered_bps_config")
+                @ExcludeMissing
+                private val tieredBpsConfig: JsonField<TieredBpsConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun tieredBpsConfig(): TieredBpsConfig =
+                    tieredBpsConfig.getRequired("tiered_bps_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_bps_config")
-                fun tieredBpsConfig(): TieredBpsConfig = tieredBpsConfig
+                @ExcludeMissing
+                fun _tieredBpsConfig(): JsonField<TieredBpsConfig> = tieredBpsConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -31563,19 +42001,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredBpsPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredBpsConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -31585,22 +42049,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredBpsConfig: TieredBpsConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredBpsConfig: JsonField<TieredBpsConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -31630,17 +42097,33 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
 
-                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) = apply {
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredBpsConfig(tieredBpsConfig: TieredBpsConfig) =
+                        tieredBpsConfig(JsonField.of(tieredBpsConfig))
+
+                    fun tieredBpsConfig(tieredBpsConfig: JsonField<TieredBpsConfig>) = apply {
                         this.tieredBpsConfig = tieredBpsConfig
                     }
 
@@ -31648,9 +42131,8 @@ constructor(
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -31659,13 +42141,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -31682,13 +42171,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -31698,12 +42195,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -31718,11 +42222,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -31730,22 +42241,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -31762,22 +42282,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -31787,12 +42322,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -31801,11 +42344,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -31814,6 +42365,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -31998,7 +42557,9 @@ constructor(
                 class TieredBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -32007,12 +42568,29 @@ constructor(
                      * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                      * specified tiers
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                     * specified tiers
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32022,13 +42600,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(tieredBpsConfig: TieredBpsConfig) = apply {
-                            tiers = tieredBpsConfig.tiers.toMutableList()
+                            tiers = tieredBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties =
                                 tieredBpsConfig.additionalProperties.toMutableMap()
                         }
@@ -32037,14 +42615,31 @@ constructor(
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a Graduated BPS pricing model, where usage is bucketed into
+                         * specified tiers
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a Graduated BPS pricing model, where usage is bucketed into
                          * specified tiers
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -32072,7 +42667,7 @@ constructor(
                         fun build(): TieredBpsConfig =
                             TieredBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -32081,33 +42676,71 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("minimum_amount") private val minimumAmount: String,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        private val minimumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Per-event basis point rate */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
 
                         /** Inclusive tier starting value */
-                        @JsonProperty("minimum_amount") fun minimumAmount(): String = minimumAmount
+                        fun minimumAmount(): String = minimumAmount.getRequired("minimum_amount")
+
+                        /** Exclusive tier ending value */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** Per unit maximum to charge */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Per-event basis point rate */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
+
+                        /** Inclusive tier starting value */
+                        @JsonProperty("minimum_amount")
+                        @ExcludeMissing
+                        fun _minimumAmount(): JsonField<String> = minimumAmount
 
                         /** Exclusive tier ending value */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** Per unit maximum to charge */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                minimumAmount()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -32117,10 +42750,10 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var minimumAmount: String? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var minimumAmount: JsonField<String>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -32134,31 +42767,46 @@ constructor(
                             }
 
                             /** Per-event basis point rate */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Per-event basis point rate */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Inclusive tier starting value */
-                            fun minimumAmount(minimumAmount: String) = apply {
+                            fun minimumAmount(minimumAmount: String) =
+                                minimumAmount(JsonField.of(minimumAmount))
+
+                            /** Inclusive tier starting value */
+                            fun minimumAmount(minimumAmount: JsonField<String>) = apply {
                                 this.minimumAmount = minimumAmount
                             }
 
                             /** Exclusive tier ending value */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Exclusive tier ending value */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** Per unit maximum to charge */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Exclusive tier ending value */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** Per unit maximum to charge */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** Per unit maximum to charge */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -32237,22 +42885,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32262,8 +42934,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -32277,10 +42949,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -32401,22 +43080,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32426,8 +43129,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -32442,10 +43145,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -32575,6 +43285,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -32656,96 +43374,229 @@ constructor(
             class NewSubscriptionBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bps_config") private val bpsConfig: BpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                private val bpsConfig: JsonField<BpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bps_config") fun bpsConfig(): BpsConfig = bpsConfig
+                fun bpsConfig(): BpsConfig = bpsConfig.getRequired("bps_config")
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bps_config")
+                @ExcludeMissing
+                fun _bpsConfig(): JsonField<BpsConfig> = bpsConfig
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -32753,19 +43604,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBpsPrice = apply {
+                    if (!validated) {
+                        bpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -32775,22 +43652,25 @@ constructor(
 
                 class Builder {
 
-                    private var bpsConfig: BpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bpsConfig: JsonField<BpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -32817,26 +43697,42 @@ constructor(
                             newSubscriptionBpsPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bpsConfig(bpsConfig: BpsConfig) = apply { this.bpsConfig = bpsConfig }
+                    fun bpsConfig(bpsConfig: BpsConfig) = bpsConfig(JsonField.of(bpsConfig))
+
+                    fun bpsConfig(bpsConfig: JsonField<BpsConfig>) = apply {
+                        this.bpsConfig = bpsConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -32845,13 +43741,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -32868,13 +43771,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -32884,12 +43795,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -32904,11 +43822,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -32916,22 +43841,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -32948,22 +43882,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -32973,12 +43922,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -32987,11 +43944,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -33000,6 +43965,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -33048,23 +44021,45 @@ constructor(
                 class BpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("bps") private val bps: Double,
-                    @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                    @JsonProperty("bps")
+                    @ExcludeMissing
+                    private val bps: JsonField<Double> = JsonMissing.of(),
+                    @JsonProperty("per_unit_maximum")
+                    @ExcludeMissing
+                    private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Basis point take rate per event */
-                    @JsonProperty("bps") fun bps(): Double = bps
+                    fun bps(): Double = bps.getRequired("bps")
+
+                    /** Optional currency amount maximum to cap spend per event */
+                    fun perUnitMaximum(): Optional<String> =
+                        Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                    /** Basis point take rate per event */
+                    @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                     /** Optional currency amount maximum to cap spend per event */
                     @JsonProperty("per_unit_maximum")
-                    fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                    @ExcludeMissing
+                    fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BpsConfig = apply {
+                        if (!validated) {
+                            bps()
+                            perUnitMaximum()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33074,8 +44069,8 @@ constructor(
 
                     class Builder {
 
-                        private var bps: Double? = null
-                        private var perUnitMaximum: String? = null
+                        private var bps: JsonField<Double>? = null
+                        private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33087,17 +44082,24 @@ constructor(
                         }
 
                         /** Basis point take rate per event */
-                        fun bps(bps: Double) = apply { this.bps = bps }
+                        fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                        /** Basis point take rate per event */
+                        fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                         /** Optional currency amount maximum to cap spend per event */
-                        fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                            this.perUnitMaximum = perUnitMaximum
-                        }
+                        fun perUnitMaximum(perUnitMaximum: String?) =
+                            perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
 
                         /** Optional currency amount maximum to cap spend per event */
                         fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                             perUnitMaximum(perUnitMaximum.orElse(null))
 
+                        /** Optional currency amount maximum to cap spend per event */
+                        fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                            this.perUnitMaximum = perUnitMaximum
+                        }
+
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                             apply {
                                 this.additionalProperties.clear()
@@ -33288,22 +44290,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33313,8 +44339,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33328,10 +44354,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -33452,22 +44485,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33477,8 +44534,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -33493,10 +44550,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -33626,6 +44690,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -33707,96 +44779,229 @@ constructor(
             class NewSubscriptionBulkBpsPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_bps_config") private val bulkBpsConfig: BulkBpsConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                private val bulkBpsConfig: JsonField<BulkBpsConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_bps_config") fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig
+                fun bulkBpsConfig(): BulkBpsConfig = bulkBpsConfig.getRequired("bulk_bps_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_bps_config")
+                @ExcludeMissing
+                fun _bulkBpsConfig(): JsonField<BulkBpsConfig> = bulkBpsConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -33804,19 +45009,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkBpsPrice = apply {
+                    if (!validated) {
+                        bulkBpsConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -33826,22 +45057,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkBpsConfig: BulkBpsConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkBpsConfig: JsonField<BulkBpsConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -33869,28 +45103,43 @@ constructor(
                                 newSubscriptionBulkBpsPrice.additionalProperties.toMutableMap()
                         }
 
-                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) = apply {
+                    fun bulkBpsConfig(bulkBpsConfig: BulkBpsConfig) =
+                        bulkBpsConfig(JsonField.of(bulkBpsConfig))
+
+                    fun bulkBpsConfig(bulkBpsConfig: JsonField<BulkBpsConfig>) = apply {
                         this.bulkBpsConfig = bulkBpsConfig
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -33899,13 +45148,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -33922,13 +45178,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -33938,12 +45202,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -33958,11 +45229,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -33970,22 +45248,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -34002,22 +45289,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -34027,12 +45329,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -34041,11 +45351,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -34054,6 +45372,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -34104,7 +45430,9 @@ constructor(
                 class BulkBpsConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
@@ -34113,12 +45441,29 @@ constructor(
                      * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
                      * tier based on total volume
                      */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /**
+                     * Tiers for a bulk BPS pricing model where all usage is aggregated to a single
+                     * tier based on total volume
+                     */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkBpsConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34128,13 +45473,13 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkBpsConfig: BulkBpsConfig) = apply {
-                            tiers = bulkBpsConfig.tiers.toMutableList()
+                            tiers = bulkBpsConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkBpsConfig.additionalProperties.toMutableMap()
                         }
 
@@ -34142,14 +45487,31 @@ constructor(
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /**
+                         * Tiers for a bulk BPS pricing model where all usage is aggregated to a
+                         * single tier based on total volume
+                         */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /**
                          * Tiers for a bulk BPS pricing model where all usage is aggregated to a
                          * single tier based on total volume
                          */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -34177,7 +45539,7 @@ constructor(
                         fun build(): BulkBpsConfig =
                             BulkBpsConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -34186,29 +45548,59 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("bps") private val bps: Double,
-                        @JsonProperty("maximum_amount") private val maximumAmount: String?,
-                        @JsonProperty("per_unit_maximum") private val perUnitMaximum: String?,
+                        @JsonProperty("bps")
+                        @ExcludeMissing
+                        private val bps: JsonField<Double> = JsonMissing.of(),
+                        @JsonProperty("maximum_amount")
+                        @ExcludeMissing
+                        private val maximumAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("per_unit_maximum")
+                        @ExcludeMissing
+                        private val perUnitMaximum: JsonField<String> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Basis points to rate on */
-                        @JsonProperty("bps") fun bps(): Double = bps
+                        fun bps(): Double = bps.getRequired("bps")
+
+                        /** Upper bound for tier */
+                        fun maximumAmount(): Optional<String> =
+                            Optional.ofNullable(maximumAmount.getNullable("maximum_amount"))
+
+                        /** The maximum amount to charge for any one event */
+                        fun perUnitMaximum(): Optional<String> =
+                            Optional.ofNullable(perUnitMaximum.getNullable("per_unit_maximum"))
+
+                        /** Basis points to rate on */
+                        @JsonProperty("bps") @ExcludeMissing fun _bps(): JsonField<Double> = bps
 
                         /** Upper bound for tier */
                         @JsonProperty("maximum_amount")
-                        fun maximumAmount(): Optional<String> = Optional.ofNullable(maximumAmount)
+                        @ExcludeMissing
+                        fun _maximumAmount(): JsonField<String> = maximumAmount
 
                         /** The maximum amount to charge for any one event */
                         @JsonProperty("per_unit_maximum")
-                        fun perUnitMaximum(): Optional<String> = Optional.ofNullable(perUnitMaximum)
+                        @ExcludeMissing
+                        fun _perUnitMaximum(): JsonField<String> = perUnitMaximum
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                bps()
+                                maximumAmount()
+                                perUnitMaximum()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -34218,9 +45610,9 @@ constructor(
 
                         class Builder {
 
-                            private var bps: Double? = null
-                            private var maximumAmount: String? = null
-                            private var perUnitMaximum: String? = null
+                            private var bps: JsonField<Double>? = null
+                            private var maximumAmount: JsonField<String> = JsonMissing.of()
+                            private var perUnitMaximum: JsonField<String> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -34233,26 +45625,37 @@ constructor(
                             }
 
                             /** Basis points to rate on */
-                            fun bps(bps: Double) = apply { this.bps = bps }
+                            fun bps(bps: Double) = bps(JsonField.of(bps))
+
+                            /** Basis points to rate on */
+                            fun bps(bps: JsonField<Double>) = apply { this.bps = bps }
 
                             /** Upper bound for tier */
-                            fun maximumAmount(maximumAmount: String?) = apply {
-                                this.maximumAmount = maximumAmount
-                            }
+                            fun maximumAmount(maximumAmount: String?) =
+                                maximumAmount(JsonField.ofNullable(maximumAmount))
 
                             /** Upper bound for tier */
                             fun maximumAmount(maximumAmount: Optional<String>) =
                                 maximumAmount(maximumAmount.orElse(null))
 
-                            /** The maximum amount to charge for any one event */
-                            fun perUnitMaximum(perUnitMaximum: String?) = apply {
-                                this.perUnitMaximum = perUnitMaximum
+                            /** Upper bound for tier */
+                            fun maximumAmount(maximumAmount: JsonField<String>) = apply {
+                                this.maximumAmount = maximumAmount
                             }
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: String?) =
+                                perUnitMaximum(JsonField.ofNullable(perUnitMaximum))
+
                             /** The maximum amount to charge for any one event */
                             fun perUnitMaximum(perUnitMaximum: Optional<String>) =
                                 perUnitMaximum(perUnitMaximum.orElse(null))
 
+                            /** The maximum amount to charge for any one event */
+                            fun perUnitMaximum(perUnitMaximum: JsonField<String>) = apply {
+                                this.perUnitMaximum = perUnitMaximum
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -34462,22 +45865,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34487,8 +45914,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -34502,10 +45929,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -34626,22 +46060,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34651,8 +46109,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -34667,10 +46125,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -34800,6 +46265,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -34881,96 +46354,229 @@ constructor(
             class NewSubscriptionBulkPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("bulk_config") private val bulkConfig: BulkConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                private val bulkConfig: JsonField<BulkConfig> = JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
-                @JsonProperty("bulk_config") fun bulkConfig(): BulkConfig = bulkConfig
+                fun bulkConfig(): BulkConfig = bulkConfig.getRequired("bulk_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                @JsonProperty("bulk_config")
+                @ExcludeMissing
+                fun _bulkConfig(): JsonField<BulkConfig> = bulkConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -34978,19 +46584,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkPrice = apply {
+                    if (!validated) {
+                        bulkConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -35000,22 +46632,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkConfig: BulkConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkConfig: JsonField<BulkConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -35042,26 +46677,42 @@ constructor(
                             newSubscriptionBulkPrice.additionalProperties.toMutableMap()
                     }
 
-                    fun bulkConfig(bulkConfig: BulkConfig) = apply { this.bulkConfig = bulkConfig }
+                    fun bulkConfig(bulkConfig: BulkConfig) = bulkConfig(JsonField.of(bulkConfig))
+
+                    fun bulkConfig(bulkConfig: JsonField<BulkConfig>) = apply {
+                        this.bulkConfig = bulkConfig
+                    }
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -35070,13 +46721,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -35093,13 +46751,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -35109,12 +46775,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -35129,11 +46802,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -35141,22 +46821,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -35173,22 +46862,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -35198,12 +46902,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -35212,11 +46924,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -35225,6 +46945,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -35273,18 +47001,34 @@ constructor(
                 class BulkConfig
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("tiers") private val tiers: List<Tier>,
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    private val tiers: JsonField<List<Tier>> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** Bulk tiers for rating based on total usage volume */
-                    @JsonProperty("tiers") fun tiers(): List<Tier> = tiers
+                    fun tiers(): List<Tier> = tiers.getRequired("tiers")
+
+                    /** Bulk tiers for rating based on total usage volume */
+                    @JsonProperty("tiers")
+                    @ExcludeMissing
+                    fun _tiers(): JsonField<List<Tier>> = tiers
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkConfig = apply {
+                        if (!validated) {
+                            tiers().forEach { it.validate() }
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35294,22 +47038,36 @@ constructor(
 
                     class Builder {
 
-                        private var tiers: MutableList<Tier>? = null
+                        private var tiers: JsonField<MutableList<Tier>>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
                         @JvmSynthetic
                         internal fun from(bulkConfig: BulkConfig) = apply {
-                            tiers = bulkConfig.tiers.toMutableList()
+                            tiers = bulkConfig.tiers.map { it.toMutableList() }
                             additionalProperties = bulkConfig.additionalProperties.toMutableMap()
                         }
 
                         /** Bulk tiers for rating based on total usage volume */
-                        fun tiers(tiers: List<Tier>) = apply { this.tiers = tiers.toMutableList() }
+                        fun tiers(tiers: List<Tier>) = tiers(JsonField.of(tiers))
+
+                        /** Bulk tiers for rating based on total usage volume */
+                        fun tiers(tiers: JsonField<List<Tier>>) = apply {
+                            this.tiers = tiers.map { it.toMutableList() }
+                        }
 
                         /** Bulk tiers for rating based on total usage volume */
                         fun addTier(tier: Tier) = apply {
-                            tiers = (tiers ?: mutableListOf()).apply { add(tier) }
+                            tiers =
+                                (tiers ?: JsonField.of(mutableListOf())).apply {
+                                    asKnown()
+                                        .orElseThrow {
+                                            IllegalStateException(
+                                                "Field was set to non-list type: ${javaClass.simpleName}"
+                                            )
+                                        }
+                                        .add(tier)
+                                }
                         }
 
                         fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
@@ -35337,7 +47095,7 @@ constructor(
                         fun build(): BulkConfig =
                             BulkConfig(
                                 checkNotNull(tiers) { "`tiers` is required but was not set" }
-                                    .toImmutable(),
+                                    .map { it.toImmutable() },
                                 additionalProperties.toImmutable()
                             )
                     }
@@ -35346,24 +47104,48 @@ constructor(
                     class Tier
                     @JsonCreator
                     private constructor(
-                        @JsonProperty("unit_amount") private val unitAmount: String,
-                        @JsonProperty("maximum_units") private val maximumUnits: Double?,
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        private val unitAmount: JsonField<String> = JsonMissing.of(),
+                        @JsonProperty("maximum_units")
+                        @ExcludeMissing
+                        private val maximumUnits: JsonField<Double> = JsonMissing.of(),
                         @JsonAnySetter
                         private val additionalProperties: Map<String, JsonValue> =
                             immutableEmptyMap(),
                     ) {
 
                         /** Amount per unit */
-                        @JsonProperty("unit_amount") fun unitAmount(): String = unitAmount
+                        fun unitAmount(): String = unitAmount.getRequired("unit_amount")
+
+                        /** Upper bound for this tier */
+                        fun maximumUnits(): Optional<Double> =
+                            Optional.ofNullable(maximumUnits.getNullable("maximum_units"))
+
+                        /** Amount per unit */
+                        @JsonProperty("unit_amount")
+                        @ExcludeMissing
+                        fun _unitAmount(): JsonField<String> = unitAmount
 
                         /** Upper bound for this tier */
                         @JsonProperty("maximum_units")
-                        fun maximumUnits(): Optional<Double> = Optional.ofNullable(maximumUnits)
+                        @ExcludeMissing
+                        fun _maximumUnits(): JsonField<Double> = maximumUnits
 
                         @JsonAnyGetter
                         @ExcludeMissing
                         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                        private var validated: Boolean = false
+
+                        fun validate(): Tier = apply {
+                            if (!validated) {
+                                unitAmount()
+                                maximumUnits()
+                                validated = true
+                            }
+                        }
+
                         fun toBuilder() = Builder().from(this)
 
                         companion object {
@@ -35373,8 +47155,8 @@ constructor(
 
                         class Builder {
 
-                            private var unitAmount: String? = null
-                            private var maximumUnits: Double? = null
+                            private var unitAmount: JsonField<String>? = null
+                            private var maximumUnits: JsonField<Double> = JsonMissing.of()
                             private var additionalProperties: MutableMap<String, JsonValue> =
                                 mutableMapOf()
 
@@ -35386,14 +47168,17 @@ constructor(
                             }
 
                             /** Amount per unit */
-                            fun unitAmount(unitAmount: String) = apply {
+                            fun unitAmount(unitAmount: String) =
+                                unitAmount(JsonField.of(unitAmount))
+
+                            /** Amount per unit */
+                            fun unitAmount(unitAmount: JsonField<String>) = apply {
                                 this.unitAmount = unitAmount
                             }
 
                             /** Upper bound for this tier */
-                            fun maximumUnits(maximumUnits: Double?) = apply {
-                                this.maximumUnits = maximumUnits
-                            }
+                            fun maximumUnits(maximumUnits: Double?) =
+                                maximumUnits(JsonField.ofNullable(maximumUnits))
 
                             /** Upper bound for this tier */
                             fun maximumUnits(maximumUnits: Double) =
@@ -35406,6 +47191,11 @@ constructor(
                             fun maximumUnits(maximumUnits: Optional<Double>) =
                                 maximumUnits(maximumUnits.orElse(null) as Double?)
 
+                            /** Upper bound for this tier */
+                            fun maximumUnits(maximumUnits: JsonField<Double>) = apply {
+                                this.maximumUnits = maximumUnits
+                            }
+
                             fun additionalProperties(additionalProperties: Map<String, JsonValue>) =
                                 apply {
                                     this.additionalProperties.clear()
@@ -35616,22 +47406,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35641,8 +47455,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -35656,10 +47470,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -35780,22 +47601,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -35805,8 +47650,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -35821,10 +47666,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -35954,6 +47806,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36035,42 +47895,166 @@ constructor(
             class NewSubscriptionThresholdTotalAmountPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("threshold_total_amount_config")
-                private val thresholdTotalAmountConfig: ThresholdTotalAmountConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("threshold_total_amount_config")
                 fun thresholdTotalAmountConfig(): ThresholdTotalAmountConfig =
+                    thresholdTotalAmountConfig.getRequired("threshold_total_amount_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("threshold_total_amount_config")
+                @ExcludeMissing
+                fun _thresholdTotalAmountConfig(): JsonField<ThresholdTotalAmountConfig> =
                     thresholdTotalAmountConfig
 
                 /**
@@ -36078,56 +48062,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -36135,19 +48128,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionThresholdTotalAmountPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        thresholdTotalAmountConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -36157,22 +48176,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var thresholdTotalAmountConfig: ThresholdTotalAmountConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -36207,27 +48230,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun thresholdTotalAmountConfig(
                         thresholdTotalAmountConfig: ThresholdTotalAmountConfig
+                    ) = thresholdTotalAmountConfig(JsonField.of(thresholdTotalAmountConfig))
+
+                    fun thresholdTotalAmountConfig(
+                        thresholdTotalAmountConfig: JsonField<ThresholdTotalAmountConfig>
                     ) = apply { this.thresholdTotalAmountConfig = thresholdTotalAmountConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -36236,13 +48275,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -36259,13 +48305,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -36275,12 +48329,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -36295,11 +48356,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -36307,22 +48375,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -36339,22 +48416,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -36364,12 +48456,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -36378,11 +48478,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -36391,6 +48499,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -36583,6 +48699,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): ThresholdTotalAmountConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36654,22 +48778,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36679,8 +48827,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -36694,10 +48842,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -36818,22 +48973,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -36843,8 +49022,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -36859,10 +49038,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -36992,6 +49178,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37073,98 +49267,230 @@ constructor(
             class NewSubscriptionTieredPackagePrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_package_config")
-                private val tieredPackageConfig: TieredPackageConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredPackageConfig: JsonField<TieredPackageConfig> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredPackageConfig(): TieredPackageConfig =
+                    tieredPackageConfig.getRequired("tiered_package_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_package_config")
-                fun tieredPackageConfig(): TieredPackageConfig = tieredPackageConfig
+                @ExcludeMissing
+                fun _tieredPackageConfig(): JsonField<TieredPackageConfig> = tieredPackageConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -37172,19 +49498,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredPackagePrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredPackageConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -37194,22 +49546,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredPackageConfig: TieredPackageConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredPackageConfig: JsonField<TieredPackageConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -37239,27 +49594,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) = apply {
-                        this.tieredPackageConfig = tieredPackageConfig
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
                     }
 
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
+
+                    fun tieredPackageConfig(tieredPackageConfig: TieredPackageConfig) =
+                        tieredPackageConfig(JsonField.of(tieredPackageConfig))
+
+                    fun tieredPackageConfig(tieredPackageConfig: JsonField<TieredPackageConfig>) =
+                        apply {
+                            this.tieredPackageConfig = tieredPackageConfig
+                        }
+
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -37268,13 +49639,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -37291,13 +49669,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -37307,12 +49693,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -37327,11 +49720,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -37339,22 +49739,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -37371,22 +49780,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -37396,12 +49820,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -37410,11 +49842,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -37423,6 +49863,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -37615,6 +50063,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredPackageConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37685,22 +50141,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37710,8 +50190,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -37725,10 +50205,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -37849,22 +50336,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -37874,8 +50385,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -37890,10 +50401,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -38023,6 +50541,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38104,98 +50630,232 @@ constructor(
             class NewSubscriptionTieredWithMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_minimum_config")
-                private val tieredWithMinimumConfig: TieredWithMinimumConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                fun tieredWithMinimumConfig(): TieredWithMinimumConfig =
+                    tieredWithMinimumConfig.getRequired("tiered_with_minimum_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("tiered_with_minimum_config")
-                fun tieredWithMinimumConfig(): TieredWithMinimumConfig = tieredWithMinimumConfig
+                @ExcludeMissing
+                fun _tieredWithMinimumConfig(): JsonField<TieredWithMinimumConfig> =
+                    tieredWithMinimumConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -38203,19 +50863,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTieredWithMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithMinimumConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -38225,22 +50911,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithMinimumConfig: TieredWithMinimumConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -38274,28 +50963,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithMinimumConfig(tieredWithMinimumConfig: TieredWithMinimumConfig) =
-                        apply {
-                            this.tieredWithMinimumConfig = tieredWithMinimumConfig
-                        }
+                        tieredWithMinimumConfig(JsonField.of(tieredWithMinimumConfig))
+
+                    fun tieredWithMinimumConfig(
+                        tieredWithMinimumConfig: JsonField<TieredWithMinimumConfig>
+                    ) = apply { this.tieredWithMinimumConfig = tieredWithMinimumConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -38304,13 +51007,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -38327,13 +51037,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -38343,12 +51061,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -38363,11 +51088,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -38375,22 +51107,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -38407,22 +51148,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -38432,12 +51188,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -38446,11 +51210,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -38459,6 +51231,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -38651,6 +51431,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38722,22 +51510,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38747,8 +51559,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -38762,10 +51574,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -38886,22 +51705,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -38911,8 +51754,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -38927,10 +51770,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -39060,6 +51910,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39141,98 +51999,232 @@ constructor(
             class NewSubscriptionUnitWithPercentPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_percent_config")
-                private val unitWithPercentConfig: UnitWithPercentConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithPercentConfig: JsonField<UnitWithPercentConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithPercentConfig(): UnitWithPercentConfig =
+                    unitWithPercentConfig.getRequired("unit_with_percent_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_percent_config")
-                fun unitWithPercentConfig(): UnitWithPercentConfig = unitWithPercentConfig
+                @ExcludeMissing
+                fun _unitWithPercentConfig(): JsonField<UnitWithPercentConfig> =
+                    unitWithPercentConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -39240,19 +52232,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithPercentPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithPercentConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -39262,22 +52280,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithPercentConfig: UnitWithPercentConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithPercentConfig: JsonField<UnitWithPercentConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -39308,28 +52329,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithPercentConfig(unitWithPercentConfig: UnitWithPercentConfig) =
-                        apply {
-                            this.unitWithPercentConfig = unitWithPercentConfig
-                        }
+                        unitWithPercentConfig(JsonField.of(unitWithPercentConfig))
+
+                    fun unitWithPercentConfig(
+                        unitWithPercentConfig: JsonField<UnitWithPercentConfig>
+                    ) = apply { this.unitWithPercentConfig = unitWithPercentConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -39338,13 +52373,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -39361,13 +52403,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -39377,12 +52427,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -39397,11 +52454,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -39409,22 +52473,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -39441,22 +52514,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -39466,12 +52554,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -39480,11 +52576,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -39493,6 +52597,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -39685,6 +52797,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithPercentConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39755,22 +52875,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39780,8 +52924,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -39795,10 +52939,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -39919,22 +53070,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -39944,8 +53119,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -39960,10 +53135,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -40093,6 +53275,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40174,42 +53364,166 @@ constructor(
             class NewSubscriptionPackageWithAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("package_with_allocation_config")
-                private val packageWithAllocationConfig: PackageWithAllocationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val packageWithAllocationConfig: JsonField<PackageWithAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("package_with_allocation_config")
                 fun packageWithAllocationConfig(): PackageWithAllocationConfig =
+                    packageWithAllocationConfig.getRequired("package_with_allocation_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("package_with_allocation_config")
+                @ExcludeMissing
+                fun _packageWithAllocationConfig(): JsonField<PackageWithAllocationConfig> =
                     packageWithAllocationConfig
 
                 /**
@@ -40217,56 +53531,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -40274,19 +53597,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionPackageWithAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        packageWithAllocationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -40296,22 +53645,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var packageWithAllocationConfig: PackageWithAllocationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var packageWithAllocationConfig:
+                        JsonField<PackageWithAllocationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -40347,27 +53701,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun packageWithAllocationConfig(
                         packageWithAllocationConfig: PackageWithAllocationConfig
+                    ) = packageWithAllocationConfig(JsonField.of(packageWithAllocationConfig))
+
+                    fun packageWithAllocationConfig(
+                        packageWithAllocationConfig: JsonField<PackageWithAllocationConfig>
                     ) = apply { this.packageWithAllocationConfig = packageWithAllocationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -40376,13 +53746,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -40399,13 +53776,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -40415,12 +53800,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -40435,11 +53827,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -40447,22 +53846,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -40479,22 +53887,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -40504,12 +53927,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -40518,11 +53949,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -40531,6 +53970,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -40723,6 +54170,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): PackageWithAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40795,22 +54250,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40820,8 +54299,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -40835,10 +54314,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -40959,22 +54445,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -40984,8 +54494,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -41000,10 +54510,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -41133,6 +54650,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41214,42 +54739,166 @@ constructor(
             class NewSubscriptionTierWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("tiered_with_proration_config")
-                private val tieredWithProrationConfig: TieredWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val tieredWithProrationConfig: JsonField<TieredWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
 
-                @JsonProperty("tiered_with_proration_config")
                 fun tieredWithProrationConfig(): TieredWithProrationConfig =
+                    tieredWithProrationConfig.getRequired("tiered_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
+
+                @JsonProperty("tiered_with_proration_config")
+                @ExcludeMissing
+                fun _tieredWithProrationConfig(): JsonField<TieredWithProrationConfig> =
                     tieredWithProrationConfig
 
                 /**
@@ -41257,56 +54906,65 @@ constructor(
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -41314,19 +54972,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionTierWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        tieredWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -41336,22 +55020,26 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var tieredWithProrationConfig: TieredWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var tieredWithProrationConfig: JsonField<TieredWithProrationConfig>? =
+                        null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -41385,27 +55073,43 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun tieredWithProrationConfig(
                         tieredWithProrationConfig: TieredWithProrationConfig
+                    ) = tieredWithProrationConfig(JsonField.of(tieredWithProrationConfig))
+
+                    fun tieredWithProrationConfig(
+                        tieredWithProrationConfig: JsonField<TieredWithProrationConfig>
                     ) = apply { this.tieredWithProrationConfig = tieredWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -41414,13 +55118,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -41437,13 +55148,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -41453,12 +55172,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -41473,11 +55199,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -41485,22 +55218,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -41517,22 +55259,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -41542,12 +55299,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -41556,11 +55321,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -41569,6 +55342,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -41761,6 +55542,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): TieredWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41832,22 +55621,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -41857,8 +55670,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -41872,10 +55685,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -41996,22 +55816,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42021,8 +55865,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -42037,10 +55881,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -42170,6 +56021,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42251,98 +56110,232 @@ constructor(
             class NewSubscriptionUnitWithProrationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("unit_with_proration_config")
-                private val unitWithProrationConfig: UnitWithProrationConfig,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val unitWithProrationConfig: JsonField<UnitWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                fun itemId(): String = itemId.getRequired("item_id")
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                fun modelType(): ModelType = modelType.getRequired("model_type")
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                fun name(): String = name.getRequired("name")
+
+                fun unitWithProrationConfig(): UnitWithProrationConfig =
+                    unitWithProrationConfig.getRequired("unit_with_proration_config")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                /** The id of the item the plan will be associated with. */
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
+
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
+
+                /** The name of the price. */
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonProperty("unit_with_proration_config")
-                fun unitWithProrationConfig(): UnitWithProrationConfig = unitWithProrationConfig
+                @ExcludeMissing
+                fun _unitWithProrationConfig(): JsonField<UnitWithProrationConfig> =
+                    unitWithProrationConfig
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -42350,19 +56343,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionUnitWithProrationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        unitWithProrationConfig().validate()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -42372,22 +56391,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var unitWithProrationConfig: UnitWithProrationConfig? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var unitWithProrationConfig: JsonField<UnitWithProrationConfig>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -42421,28 +56443,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     fun unitWithProrationConfig(unitWithProrationConfig: UnitWithProrationConfig) =
-                        apply {
-                            this.unitWithProrationConfig = unitWithProrationConfig
-                        }
+                        unitWithProrationConfig(JsonField.of(unitWithProrationConfig))
+
+                    fun unitWithProrationConfig(
+                        unitWithProrationConfig: JsonField<UnitWithProrationConfig>
+                    ) = apply { this.unitWithProrationConfig = unitWithProrationConfig }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -42451,13 +56487,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -42474,13 +56517,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -42490,12 +56541,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -42510,11 +56568,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -42522,22 +56587,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -42554,22 +56628,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -42579,12 +56668,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -42593,11 +56690,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -42606,6 +56711,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -42798,6 +56911,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): UnitWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42869,22 +56990,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -42894,8 +57039,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -42909,10 +57054,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -43033,22 +57185,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43058,8 +57234,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -43074,10 +57250,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -43207,6 +57390,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43288,98 +57479,232 @@ constructor(
             class NewSubscriptionGroupedAllocationPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_allocation_config")
-                private val groupedAllocationConfig: GroupedAllocationConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedAllocationConfig: JsonField<GroupedAllocationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                fun groupedAllocationConfig(): GroupedAllocationConfig =
+                    groupedAllocationConfig.getRequired("grouped_allocation_config")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 @JsonProperty("grouped_allocation_config")
-                fun groupedAllocationConfig(): GroupedAllocationConfig = groupedAllocationConfig
+                @ExcludeMissing
+                fun _groupedAllocationConfig(): JsonField<GroupedAllocationConfig> =
+                    groupedAllocationConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -43387,19 +57712,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedAllocationPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedAllocationConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -43409,22 +57760,25 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
-                    private var groupedAllocationConfig: GroupedAllocationConfig? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var groupedAllocationConfig: JsonField<GroupedAllocationConfig>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -43458,28 +57812,42 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedAllocationConfig(groupedAllocationConfig: GroupedAllocationConfig) =
-                        apply {
-                            this.groupedAllocationConfig = groupedAllocationConfig
-                        }
+                        groupedAllocationConfig(JsonField.of(groupedAllocationConfig))
+
+                    fun groupedAllocationConfig(
+                        groupedAllocationConfig: JsonField<GroupedAllocationConfig>
+                    ) = apply { this.groupedAllocationConfig = groupedAllocationConfig }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -43488,13 +57856,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -43511,13 +57886,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -43527,12 +57910,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -43547,11 +57937,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -43559,22 +57956,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -43591,22 +57997,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -43616,12 +58037,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -43630,11 +58059,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -43643,6 +58080,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -43783,6 +58228,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedAllocationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43906,22 +58359,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -43931,8 +58408,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -43946,10 +58423,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -44070,22 +58554,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44095,8 +58603,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -44111,10 +58619,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -44244,6 +58759,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44325,99 +58848,235 @@ constructor(
             class NewSubscriptionGroupedWithProratedMinimumPrice
             @JsonCreator
             private constructor(
-                @JsonProperty("cadence") private val cadence: Cadence,
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
                 @JsonProperty("grouped_with_prorated_minimum_config")
-                private val groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val groupedWithProratedMinimumConfig:
+                    JsonField<GroupedWithProratedMinimumConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                fun cadence(): Cadence = cadence.getRequired("cadence")
 
-                @JsonProperty("grouped_with_prorated_minimum_config")
                 fun groupedWithProratedMinimumConfig(): GroupedWithProratedMinimumConfig =
-                    groupedWithProratedMinimumConfig
+                    groupedWithProratedMinimumConfig.getRequired(
+                        "grouped_with_prorated_minimum_config"
+                    )
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
+                /** The cadence to bill for this price on. */
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
+
+                @JsonProperty("grouped_with_prorated_minimum_config")
+                @ExcludeMissing
+                fun _groupedWithProratedMinimumConfig():
+                    JsonField<GroupedWithProratedMinimumConfig> = groupedWithProratedMinimumConfig
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -44425,19 +59084,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionGroupedWithProratedMinimumPrice = apply {
+                    if (!validated) {
+                        cadence()
+                        groupedWithProratedMinimumConfig().validate()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -44447,24 +59132,27 @@ constructor(
 
                 class Builder {
 
-                    private var cadence: Cadence? = null
+                    private var cadence: JsonField<Cadence>? = null
                     private var groupedWithProratedMinimumConfig:
-                        GroupedWithProratedMinimumConfig? =
+                        JsonField<GroupedWithProratedMinimumConfig>? =
                         null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -44505,29 +59193,49 @@ constructor(
                     }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     fun groupedWithProratedMinimumConfig(
                         groupedWithProratedMinimumConfig: GroupedWithProratedMinimumConfig
+                    ) =
+                        groupedWithProratedMinimumConfig(
+                            JsonField.of(groupedWithProratedMinimumConfig)
+                        )
+
+                    fun groupedWithProratedMinimumConfig(
+                        groupedWithProratedMinimumConfig:
+                            JsonField<GroupedWithProratedMinimumConfig>
                     ) = apply {
                         this.groupedWithProratedMinimumConfig = groupedWithProratedMinimumConfig
                     }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
+
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: String) = name(JsonField.of(name))
+
+                    /** The name of the price. */
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -44536,13 +59244,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -44559,13 +59274,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -44575,12 +59298,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -44595,11 +59325,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -44607,22 +59344,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -44639,22 +59385,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -44664,12 +59425,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -44678,11 +59447,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -44691,6 +59468,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -44831,6 +59616,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): GroupedWithProratedMinimumConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44956,22 +59749,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -44981,8 +59798,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -44996,10 +59813,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -45120,22 +59944,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
+
+                    /** The unit of billing period duration. */
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45145,8 +59993,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -45161,10 +60009,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -45294,6 +60149,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45376,97 +60239,231 @@ constructor(
             @JsonCreator
             private constructor(
                 @JsonProperty("bulk_with_proration_config")
-                private val bulkWithProrationConfig: BulkWithProrationConfig,
-                @JsonProperty("cadence") private val cadence: Cadence,
-                @JsonProperty("item_id") private val itemId: String,
-                @JsonProperty("model_type") private val modelType: ModelType,
-                @JsonProperty("name") private val name: String,
-                @JsonProperty("billable_metric_id") private val billableMetricId: String?,
-                @JsonProperty("billed_in_advance") private val billedInAdvance: Boolean?,
+                @ExcludeMissing
+                private val bulkWithProrationConfig: JsonField<BulkWithProrationConfig> =
+                    JsonMissing.of(),
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                private val cadence: JsonField<Cadence> = JsonMissing.of(),
+                @JsonProperty("item_id")
+                @ExcludeMissing
+                private val itemId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                private val modelType: JsonField<ModelType> = JsonMissing.of(),
+                @JsonProperty("name")
+                @ExcludeMissing
+                private val name: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billable_metric_id")
+                @ExcludeMissing
+                private val billableMetricId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("billed_in_advance")
+                @ExcludeMissing
+                private val billedInAdvance: JsonField<Boolean> = JsonMissing.of(),
                 @JsonProperty("billing_cycle_configuration")
-                private val billingCycleConfiguration: BillingCycleConfiguration?,
-                @JsonProperty("conversion_rate") private val conversionRate: Double?,
-                @JsonProperty("currency") private val currency: String?,
-                @JsonProperty("external_price_id") private val externalPriceId: String?,
-                @JsonProperty("fixed_price_quantity") private val fixedPriceQuantity: Double?,
-                @JsonProperty("invoice_grouping_key") private val invoiceGroupingKey: String?,
+                @ExcludeMissing
+                private val billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("conversion_rate")
+                @ExcludeMissing
+                private val conversionRate: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("currency")
+                @ExcludeMissing
+                private val currency: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("external_price_id")
+                @ExcludeMissing
+                private val externalPriceId: JsonField<String> = JsonMissing.of(),
+                @JsonProperty("fixed_price_quantity")
+                @ExcludeMissing
+                private val fixedPriceQuantity: JsonField<Double> = JsonMissing.of(),
+                @JsonProperty("invoice_grouping_key")
+                @ExcludeMissing
+                private val invoiceGroupingKey: JsonField<String> = JsonMissing.of(),
                 @JsonProperty("invoicing_cycle_configuration")
-                private val invoicingCycleConfiguration: InvoicingCycleConfiguration?,
-                @JsonProperty("metadata") private val metadata: Metadata?,
-                @JsonProperty("reference_id") private val referenceId: String?,
+                @ExcludeMissing
+                private val invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration> =
+                    JsonMissing.of(),
+                @JsonProperty("metadata")
+                @ExcludeMissing
+                private val metadata: JsonField<Metadata> = JsonMissing.of(),
+                @JsonProperty("reference_id")
+                @ExcludeMissing
+                private val referenceId: JsonField<String> = JsonMissing.of(),
                 @JsonAnySetter
                 private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
             ) {
 
+                fun bulkWithProrationConfig(): BulkWithProrationConfig =
+                    bulkWithProrationConfig.getRequired("bulk_with_proration_config")
+
+                /** The cadence to bill for this price on. */
+                fun cadence(): Cadence = cadence.getRequired("cadence")
+
+                /** The id of the item the plan will be associated with. */
+                fun itemId(): String = itemId.getRequired("item_id")
+
+                fun modelType(): ModelType = modelType.getRequired("model_type")
+
+                /** The name of the price. */
+                fun name(): String = name.getRequired("name")
+
+                /**
+                 * The id of the billable metric for the price. Only needed if the price is
+                 * usage-based.
+                 */
+                fun billableMetricId(): Optional<String> =
+                    Optional.ofNullable(billableMetricId.getNullable("billable_metric_id"))
+
+                /**
+                 * If the Price represents a fixed cost, the price will be billed in-advance if this
+                 * is true, and in-arrears if this is false.
+                 */
+                fun billedInAdvance(): Optional<Boolean> =
+                    Optional.ofNullable(billedInAdvance.getNullable("billed_in_advance"))
+
+                /**
+                 * For custom cadence: specifies the duration of the billing period in days or
+                 * months.
+                 */
+                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
+                    Optional.ofNullable(
+                        billingCycleConfiguration.getNullable("billing_cycle_configuration")
+                    )
+
+                /** The per unit conversion rate of the price currency to the invoicing currency. */
+                fun conversionRate(): Optional<Double> =
+                    Optional.ofNullable(conversionRate.getNullable("conversion_rate"))
+
+                /**
+                 * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                 * price is billed.
+                 */
+                fun currency(): Optional<String> =
+                    Optional.ofNullable(currency.getNullable("currency"))
+
+                /** An alias for the price. */
+                fun externalPriceId(): Optional<String> =
+                    Optional.ofNullable(externalPriceId.getNullable("external_price_id"))
+
+                /**
+                 * If the Price represents a fixed cost, this represents the quantity of units
+                 * applied.
+                 */
+                fun fixedPriceQuantity(): Optional<Double> =
+                    Optional.ofNullable(fixedPriceQuantity.getNullable("fixed_price_quantity"))
+
+                /** The property used to group this price on an invoice */
+                fun invoiceGroupingKey(): Optional<String> =
+                    Optional.ofNullable(invoiceGroupingKey.getNullable("invoice_grouping_key"))
+
+                /**
+                 * Within each billing cycle, specifies the cadence at which invoices are produced.
+                 * If unspecified, a single invoice is produced per billing cycle.
+                 */
+                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
+                    Optional.ofNullable(
+                        invoicingCycleConfiguration.getNullable("invoicing_cycle_configuration")
+                    )
+
+                /**
+                 * User-specified key/value pairs for the resource. Individual keys can be removed
+                 * by setting the value to `null`, and the entire metadata mapping can be cleared by
+                 * setting `metadata` to `null`.
+                 */
+                fun metadata(): Optional<Metadata> =
+                    Optional.ofNullable(metadata.getNullable("metadata"))
+
+                /**
+                 * A transient ID that can be used to reference this price when adding adjustments
+                 * in the same API call.
+                 */
+                fun referenceId(): Optional<String> =
+                    Optional.ofNullable(referenceId.getNullable("reference_id"))
+
                 @JsonProperty("bulk_with_proration_config")
-                fun bulkWithProrationConfig(): BulkWithProrationConfig = bulkWithProrationConfig
+                @ExcludeMissing
+                fun _bulkWithProrationConfig(): JsonField<BulkWithProrationConfig> =
+                    bulkWithProrationConfig
 
                 /** The cadence to bill for this price on. */
-                @JsonProperty("cadence") fun cadence(): Cadence = cadence
+                @JsonProperty("cadence")
+                @ExcludeMissing
+                fun _cadence(): JsonField<Cadence> = cadence
 
                 /** The id of the item the plan will be associated with. */
-                @JsonProperty("item_id") fun itemId(): String = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
-                @JsonProperty("model_type") fun modelType(): ModelType = modelType
+                @JsonProperty("model_type")
+                @ExcludeMissing
+                fun _modelType(): JsonField<ModelType> = modelType
 
                 /** The name of the price. */
-                @JsonProperty("name") fun name(): String = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 /**
                  * The id of the billable metric for the price. Only needed if the price is
                  * usage-based.
                  */
                 @JsonProperty("billable_metric_id")
-                fun billableMetricId(): Optional<String> = Optional.ofNullable(billableMetricId)
+                @ExcludeMissing
+                fun _billableMetricId(): JsonField<String> = billableMetricId
 
                 /**
                  * If the Price represents a fixed cost, the price will be billed in-advance if this
                  * is true, and in-arrears if this is false.
                  */
                 @JsonProperty("billed_in_advance")
-                fun billedInAdvance(): Optional<Boolean> = Optional.ofNullable(billedInAdvance)
+                @ExcludeMissing
+                fun _billedInAdvance(): JsonField<Boolean> = billedInAdvance
 
                 /**
                  * For custom cadence: specifies the duration of the billing period in days or
                  * months.
                  */
                 @JsonProperty("billing_cycle_configuration")
-                fun billingCycleConfiguration(): Optional<BillingCycleConfiguration> =
-                    Optional.ofNullable(billingCycleConfiguration)
+                @ExcludeMissing
+                fun _billingCycleConfiguration(): JsonField<BillingCycleConfiguration> =
+                    billingCycleConfiguration
 
                 /** The per unit conversion rate of the price currency to the invoicing currency. */
                 @JsonProperty("conversion_rate")
-                fun conversionRate(): Optional<Double> = Optional.ofNullable(conversionRate)
+                @ExcludeMissing
+                fun _conversionRate(): JsonField<Double> = conversionRate
 
                 /**
                  * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                  * price is billed.
                  */
                 @JsonProperty("currency")
-                fun currency(): Optional<String> = Optional.ofNullable(currency)
+                @ExcludeMissing
+                fun _currency(): JsonField<String> = currency
 
                 /** An alias for the price. */
                 @JsonProperty("external_price_id")
-                fun externalPriceId(): Optional<String> = Optional.ofNullable(externalPriceId)
+                @ExcludeMissing
+                fun _externalPriceId(): JsonField<String> = externalPriceId
 
                 /**
                  * If the Price represents a fixed cost, this represents the quantity of units
                  * applied.
                  */
                 @JsonProperty("fixed_price_quantity")
-                fun fixedPriceQuantity(): Optional<Double> = Optional.ofNullable(fixedPriceQuantity)
+                @ExcludeMissing
+                fun _fixedPriceQuantity(): JsonField<Double> = fixedPriceQuantity
 
                 /** The property used to group this price on an invoice */
                 @JsonProperty("invoice_grouping_key")
-                fun invoiceGroupingKey(): Optional<String> = Optional.ofNullable(invoiceGroupingKey)
+                @ExcludeMissing
+                fun _invoiceGroupingKey(): JsonField<String> = invoiceGroupingKey
 
                 /**
                  * Within each billing cycle, specifies the cadence at which invoices are produced.
                  * If unspecified, a single invoice is produced per billing cycle.
                  */
                 @JsonProperty("invoicing_cycle_configuration")
-                fun invoicingCycleConfiguration(): Optional<InvoicingCycleConfiguration> =
-                    Optional.ofNullable(invoicingCycleConfiguration)
+                @ExcludeMissing
+                fun _invoicingCycleConfiguration(): JsonField<InvoicingCycleConfiguration> =
+                    invoicingCycleConfiguration
 
                 /**
                  * User-specified key/value pairs for the resource. Individual keys can be removed
@@ -45474,19 +60471,45 @@ constructor(
                  * setting `metadata` to `null`.
                  */
                 @JsonProperty("metadata")
-                fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+                @ExcludeMissing
+                fun _metadata(): JsonField<Metadata> = metadata
 
                 /**
                  * A transient ID that can be used to reference this price when adding adjustments
                  * in the same API call.
                  */
                 @JsonProperty("reference_id")
-                fun referenceId(): Optional<String> = Optional.ofNullable(referenceId)
+                @ExcludeMissing
+                fun _referenceId(): JsonField<String> = referenceId
 
                 @JsonAnyGetter
                 @ExcludeMissing
                 fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                private var validated: Boolean = false
+
+                fun validate(): NewSubscriptionBulkWithProrationPrice = apply {
+                    if (!validated) {
+                        bulkWithProrationConfig().validate()
+                        cadence()
+                        itemId()
+                        modelType()
+                        name()
+                        billableMetricId()
+                        billedInAdvance()
+                        billingCycleConfiguration().map { it.validate() }
+                        conversionRate()
+                        currency()
+                        externalPriceId()
+                        fixedPriceQuantity()
+                        invoiceGroupingKey()
+                        invoicingCycleConfiguration().map { it.validate() }
+                        metadata().map { it.validate() }
+                        referenceId()
+                        validated = true
+                    }
+                }
+
                 fun toBuilder() = Builder().from(this)
 
                 companion object {
@@ -45496,22 +60519,25 @@ constructor(
 
                 class Builder {
 
-                    private var bulkWithProrationConfig: BulkWithProrationConfig? = null
-                    private var cadence: Cadence? = null
-                    private var itemId: String? = null
-                    private var modelType: ModelType? = null
-                    private var name: String? = null
-                    private var billableMetricId: String? = null
-                    private var billedInAdvance: Boolean? = null
-                    private var billingCycleConfiguration: BillingCycleConfiguration? = null
-                    private var conversionRate: Double? = null
-                    private var currency: String? = null
-                    private var externalPriceId: String? = null
-                    private var fixedPriceQuantity: Double? = null
-                    private var invoiceGroupingKey: String? = null
-                    private var invoicingCycleConfiguration: InvoicingCycleConfiguration? = null
-                    private var metadata: Metadata? = null
-                    private var referenceId: String? = null
+                    private var bulkWithProrationConfig: JsonField<BulkWithProrationConfig>? = null
+                    private var cadence: JsonField<Cadence>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var modelType: JsonField<ModelType>? = null
+                    private var name: JsonField<String>? = null
+                    private var billableMetricId: JsonField<String> = JsonMissing.of()
+                    private var billedInAdvance: JsonField<Boolean> = JsonMissing.of()
+                    private var billingCycleConfiguration: JsonField<BillingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var conversionRate: JsonField<Double> = JsonMissing.of()
+                    private var currency: JsonField<String> = JsonMissing.of()
+                    private var externalPriceId: JsonField<String> = JsonMissing.of()
+                    private var fixedPriceQuantity: JsonField<Double> = JsonMissing.of()
+                    private var invoiceGroupingKey: JsonField<String> = JsonMissing.of()
+                    private var invoicingCycleConfiguration:
+                        JsonField<InvoicingCycleConfiguration> =
+                        JsonMissing.of()
+                    private var metadata: JsonField<Metadata> = JsonMissing.of()
+                    private var referenceId: JsonField<String> = JsonMissing.of()
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -45545,28 +60571,42 @@ constructor(
                     }
 
                     fun bulkWithProrationConfig(bulkWithProrationConfig: BulkWithProrationConfig) =
-                        apply {
-                            this.bulkWithProrationConfig = bulkWithProrationConfig
-                        }
+                        bulkWithProrationConfig(JsonField.of(bulkWithProrationConfig))
+
+                    fun bulkWithProrationConfig(
+                        bulkWithProrationConfig: JsonField<BulkWithProrationConfig>
+                    ) = apply { this.bulkWithProrationConfig = bulkWithProrationConfig }
 
                     /** The cadence to bill for this price on. */
-                    fun cadence(cadence: Cadence) = apply { this.cadence = cadence }
+                    fun cadence(cadence: Cadence) = cadence(JsonField.of(cadence))
+
+                    /** The cadence to bill for this price on. */
+                    fun cadence(cadence: JsonField<Cadence>) = apply { this.cadence = cadence }
 
                     /** The id of the item the plan will be associated with. */
-                    fun itemId(itemId: String) = apply { this.itemId = itemId }
+                    fun itemId(itemId: String) = itemId(JsonField.of(itemId))
 
-                    fun modelType(modelType: ModelType) = apply { this.modelType = modelType }
+                    /** The id of the item the plan will be associated with. */
+                    fun itemId(itemId: JsonField<String>) = apply { this.itemId = itemId }
+
+                    fun modelType(modelType: ModelType) = modelType(JsonField.of(modelType))
+
+                    fun modelType(modelType: JsonField<ModelType>) = apply {
+                        this.modelType = modelType
+                    }
+
+                    /** The name of the price. */
+                    fun name(name: String) = name(JsonField.of(name))
 
                     /** The name of the price. */
-                    fun name(name: String) = apply { this.name = name }
+                    fun name(name: JsonField<String>) = apply { this.name = name }
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
                      * usage-based.
                      */
-                    fun billableMetricId(billableMetricId: String?) = apply {
-                        this.billableMetricId = billableMetricId
-                    }
+                    fun billableMetricId(billableMetricId: String?) =
+                        billableMetricId(JsonField.ofNullable(billableMetricId))
 
                     /**
                      * The id of the billable metric for the price. Only needed if the price is
@@ -45575,13 +60615,20 @@ constructor(
                     fun billableMetricId(billableMetricId: Optional<String>) =
                         billableMetricId(billableMetricId.orElse(null))
 
+                    /**
+                     * The id of the billable metric for the price. Only needed if the price is
+                     * usage-based.
+                     */
+                    fun billableMetricId(billableMetricId: JsonField<String>) = apply {
+                        this.billableMetricId = billableMetricId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
                      * this is true, and in-arrears if this is false.
                      */
-                    fun billedInAdvance(billedInAdvance: Boolean?) = apply {
-                        this.billedInAdvance = billedInAdvance
-                    }
+                    fun billedInAdvance(billedInAdvance: Boolean?) =
+                        billedInAdvance(JsonField.ofNullable(billedInAdvance))
 
                     /**
                      * If the Price represents a fixed cost, the price will be billed in-advance if
@@ -45598,13 +60645,21 @@ constructor(
                     fun billedInAdvance(billedInAdvance: Optional<Boolean>) =
                         billedInAdvance(billedInAdvance.orElse(null) as Boolean?)
 
+                    /**
+                     * If the Price represents a fixed cost, the price will be billed in-advance if
+                     * this is true, and in-arrears if this is false.
+                     */
+                    fun billedInAdvance(billedInAdvance: JsonField<Boolean>) = apply {
+                        this.billedInAdvance = billedInAdvance
+                    }
+
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
                      * months.
                      */
                     fun billingCycleConfiguration(
                         billingCycleConfiguration: BillingCycleConfiguration?
-                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+                    ) = billingCycleConfiguration(JsonField.ofNullable(billingCycleConfiguration))
 
                     /**
                      * For custom cadence: specifies the duration of the billing period in days or
@@ -45614,12 +60669,19 @@ constructor(
                         billingCycleConfiguration: Optional<BillingCycleConfiguration>
                     ) = billingCycleConfiguration(billingCycleConfiguration.orElse(null))
 
+                    /**
+                     * For custom cadence: specifies the duration of the billing period in days or
+                     * months.
+                     */
+                    fun billingCycleConfiguration(
+                        billingCycleConfiguration: JsonField<BillingCycleConfiguration>
+                    ) = apply { this.billingCycleConfiguration = billingCycleConfiguration }
+
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
                      */
-                    fun conversionRate(conversionRate: Double?) = apply {
-                        this.conversionRate = conversionRate
-                    }
+                    fun conversionRate(conversionRate: Double?) =
+                        conversionRate(JsonField.ofNullable(conversionRate))
 
                     /**
                      * The per unit conversion rate of the price currency to the invoicing currency.
@@ -45634,11 +60696,18 @@ constructor(
                     fun conversionRate(conversionRate: Optional<Double>) =
                         conversionRate(conversionRate.orElse(null) as Double?)
 
+                    /**
+                     * The per unit conversion rate of the price currency to the invoicing currency.
+                     */
+                    fun conversionRate(conversionRate: JsonField<Double>) = apply {
+                        this.conversionRate = conversionRate
+                    }
+
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
                      * price is billed.
                      */
-                    fun currency(currency: String?) = apply { this.currency = currency }
+                    fun currency(currency: String?) = currency(JsonField.ofNullable(currency))
 
                     /**
                      * An ISO 4217 currency string, or custom pricing unit identifier, in which this
@@ -45646,22 +60715,31 @@ constructor(
                      */
                     fun currency(currency: Optional<String>) = currency(currency.orElse(null))
 
+                    /**
+                     * An ISO 4217 currency string, or custom pricing unit identifier, in which this
+                     * price is billed.
+                     */
+                    fun currency(currency: JsonField<String>) = apply { this.currency = currency }
+
                     /** An alias for the price. */
-                    fun externalPriceId(externalPriceId: String?) = apply {
-                        this.externalPriceId = externalPriceId
-                    }
+                    fun externalPriceId(externalPriceId: String?) =
+                        externalPriceId(JsonField.ofNullable(externalPriceId))
 
                     /** An alias for the price. */
                     fun externalPriceId(externalPriceId: Optional<String>) =
                         externalPriceId(externalPriceId.orElse(null))
 
+                    /** An alias for the price. */
+                    fun externalPriceId(externalPriceId: JsonField<String>) = apply {
+                        this.externalPriceId = externalPriceId
+                    }
+
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
                      * applied.
                      */
-                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) = apply {
-                        this.fixedPriceQuantity = fixedPriceQuantity
-                    }
+                    fun fixedPriceQuantity(fixedPriceQuantity: Double?) =
+                        fixedPriceQuantity(JsonField.ofNullable(fixedPriceQuantity))
 
                     /**
                      * If the Price represents a fixed cost, this represents the quantity of units
@@ -45678,22 +60756,37 @@ constructor(
                     fun fixedPriceQuantity(fixedPriceQuantity: Optional<Double>) =
                         fixedPriceQuantity(fixedPriceQuantity.orElse(null) as Double?)
 
-                    /** The property used to group this price on an invoice */
-                    fun invoiceGroupingKey(invoiceGroupingKey: String?) = apply {
-                        this.invoiceGroupingKey = invoiceGroupingKey
+                    /**
+                     * If the Price represents a fixed cost, this represents the quantity of units
+                     * applied.
+                     */
+                    fun fixedPriceQuantity(fixedPriceQuantity: JsonField<Double>) = apply {
+                        this.fixedPriceQuantity = fixedPriceQuantity
                     }
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: String?) =
+                        invoiceGroupingKey(JsonField.ofNullable(invoiceGroupingKey))
+
                     /** The property used to group this price on an invoice */
                     fun invoiceGroupingKey(invoiceGroupingKey: Optional<String>) =
                         invoiceGroupingKey(invoiceGroupingKey.orElse(null))
 
+                    /** The property used to group this price on an invoice */
+                    fun invoiceGroupingKey(invoiceGroupingKey: JsonField<String>) = apply {
+                        this.invoiceGroupingKey = invoiceGroupingKey
+                    }
+
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
                      * produced. If unspecified, a single invoice is produced per billing cycle.
                      */
                     fun invoicingCycleConfiguration(
                         invoicingCycleConfiguration: InvoicingCycleConfiguration?
-                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+                    ) =
+                        invoicingCycleConfiguration(
+                            JsonField.ofNullable(invoicingCycleConfiguration)
+                        )
 
                     /**
                      * Within each billing cycle, specifies the cadence at which invoices are
@@ -45703,12 +60796,20 @@ constructor(
                         invoicingCycleConfiguration: Optional<InvoicingCycleConfiguration>
                     ) = invoicingCycleConfiguration(invoicingCycleConfiguration.orElse(null))
 
+                    /**
+                     * Within each billing cycle, specifies the cadence at which invoices are
+                     * produced. If unspecified, a single invoice is produced per billing cycle.
+                     */
+                    fun invoicingCycleConfiguration(
+                        invoicingCycleConfiguration: JsonField<InvoicingCycleConfiguration>
+                    ) = apply { this.invoicingCycleConfiguration = invoicingCycleConfiguration }
+
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
                      * removed by setting the value to `null`, and the entire metadata mapping can
                      * be cleared by setting `metadata` to `null`.
                      */
-                    fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+                    fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
                     /**
                      * User-specified key/value pairs for the resource. Individual keys can be
@@ -45717,11 +60818,19 @@ constructor(
                      */
                     fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+                    /**
+                     * User-specified key/value pairs for the resource. Individual keys can be
+                     * removed by setting the value to `null`, and the entire metadata mapping can
+                     * be cleared by setting `metadata` to `null`.
+                     */
+                    fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
                     /**
                      * A transient ID that can be used to reference this price when adding
                      * adjustments in the same API call.
                      */
-                    fun referenceId(referenceId: String?) = apply { this.referenceId = referenceId }
+                    fun referenceId(referenceId: String?) =
+                        referenceId(JsonField.ofNullable(referenceId))
 
                     /**
                      * A transient ID that can be used to reference this price when adding
@@ -45730,6 +60839,14 @@ constructor(
                     fun referenceId(referenceId: Optional<String>) =
                         referenceId(referenceId.orElse(null))
 
+                    /**
+                     * A transient ID that can be used to reference this price when adding
+                     * adjustments in the same API call.
+                     */
+                    fun referenceId(referenceId: JsonField<String>) = apply {
+                        this.referenceId = referenceId
+                    }
+
                     fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                         this.additionalProperties.clear()
                         putAllAdditionalProperties(additionalProperties)
@@ -45788,6 +60905,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BulkWithProrationConfig = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -45993,22 +61118,46 @@ constructor(
                 class BillingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): BillingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -46018,8 +61167,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -46033,10 +61182,17 @@ constructor(
                             }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -46157,22 +61313,46 @@ constructor(
                 class InvoicingCycleConfiguration
                 @JsonCreator
                 private constructor(
-                    @JsonProperty("duration") private val duration: Long,
-                    @JsonProperty("duration_unit") private val durationUnit: DurationUnit,
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    private val duration: JsonField<Long> = JsonMissing.of(),
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    private val durationUnit: JsonField<DurationUnit> = JsonMissing.of(),
                     @JsonAnySetter
                     private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
                 ) {
 
                     /** The duration of the billing period. */
-                    @JsonProperty("duration") fun duration(): Long = duration
+                    fun duration(): Long = duration.getRequired("duration")
+
+                    /** The unit of billing period duration. */
+                    fun durationUnit(): DurationUnit = durationUnit.getRequired("duration_unit")
+
+                    /** The duration of the billing period. */
+                    @JsonProperty("duration")
+                    @ExcludeMissing
+                    fun _duration(): JsonField<Long> = duration
 
                     /** The unit of billing period duration. */
-                    @JsonProperty("duration_unit") fun durationUnit(): DurationUnit = durationUnit
+                    @JsonProperty("duration_unit")
+                    @ExcludeMissing
+                    fun _durationUnit(): JsonField<DurationUnit> = durationUnit
 
                     @JsonAnyGetter
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): InvoicingCycleConfiguration = apply {
+                        if (!validated) {
+                            duration()
+                            durationUnit()
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
@@ -46182,8 +61362,8 @@ constructor(
 
                     class Builder {
 
-                        private var duration: Long? = null
-                        private var durationUnit: DurationUnit? = null
+                        private var duration: JsonField<Long>? = null
+                        private var durationUnit: JsonField<DurationUnit>? = null
                         private var additionalProperties: MutableMap<String, JsonValue> =
                             mutableMapOf()
 
@@ -46198,10 +61378,17 @@ constructor(
                         }
 
                         /** The duration of the billing period. */
-                        fun duration(duration: Long) = apply { this.duration = duration }
+                        fun duration(duration: Long) = duration(JsonField.of(duration))
+
+                        /** The duration of the billing period. */
+                        fun duration(duration: JsonField<Long>) = apply { this.duration = duration }
+
+                        /** The unit of billing period duration. */
+                        fun durationUnit(durationUnit: DurationUnit) =
+                            durationUnit(JsonField.of(durationUnit))
 
                         /** The unit of billing period duration. */
-                        fun durationUnit(durationUnit: DurationUnit) = apply {
+                        fun durationUnit(durationUnit: JsonField<DurationUnit>) = apply {
                             this.durationUnit = durationUnit
                         }
 
@@ -46331,6 +61518,14 @@ constructor(
                     @ExcludeMissing
                     fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+                    private var validated: Boolean = false
+
+                    fun validate(): Metadata = apply {
+                        if (!validated) {
+                            validated = true
+                        }
+                    }
+
                     fun toBuilder() = Builder().from(this)
 
                     companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeResponse.kt
index b6fb1c25..25267042 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionSchedulePlanChangeResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -454,7 +474,10 @@ private constructor(
         ) = apply {
             id = subscriptionSchedulePlanChangeResponse.id
             activePlanPhaseOrder = subscriptionSchedulePlanChangeResponse.activePlanPhaseOrder
-            adjustmentIntervals = subscriptionSchedulePlanChangeResponse.adjustmentIntervals
+            adjustmentIntervals =
+                subscriptionSchedulePlanChangeResponse.adjustmentIntervals.map {
+                    it.toMutableList()
+                }
             autoCollection = subscriptionSchedulePlanChangeResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionSchedulePlanChangeResponse.billingCycleAnchorConfiguration
@@ -466,17 +489,23 @@ private constructor(
                 subscriptionSchedulePlanChangeResponse.currentBillingPeriodStartDate
             customer = subscriptionSchedulePlanChangeResponse.customer
             defaultInvoiceMemo = subscriptionSchedulePlanChangeResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionSchedulePlanChangeResponse.discountIntervals
+            discountIntervals =
+                subscriptionSchedulePlanChangeResponse.discountIntervals.map { it.toMutableList() }
             endDate = subscriptionSchedulePlanChangeResponse.endDate
             fixedFeeQuantitySchedule =
-                subscriptionSchedulePlanChangeResponse.fixedFeeQuantitySchedule
+                subscriptionSchedulePlanChangeResponse.fixedFeeQuantitySchedule.map {
+                    it.toMutableList()
+                }
             invoicingThreshold = subscriptionSchedulePlanChangeResponse.invoicingThreshold
-            maximumIntervals = subscriptionSchedulePlanChangeResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionSchedulePlanChangeResponse.maximumIntervals.map { it.toMutableList() }
             metadata = subscriptionSchedulePlanChangeResponse.metadata
-            minimumIntervals = subscriptionSchedulePlanChangeResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionSchedulePlanChangeResponse.minimumIntervals.map { it.toMutableList() }
             netTerms = subscriptionSchedulePlanChangeResponse.netTerms
             plan = subscriptionSchedulePlanChangeResponse.plan
-            priceIntervals = subscriptionSchedulePlanChangeResponse.priceIntervals
+            priceIntervals =
+                subscriptionSchedulePlanChangeResponse.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscriptionSchedulePlanChangeResponse.redeemedCoupon
             startDate = subscriptionSchedulePlanChangeResponse.startDate
             status = subscriptionSchedulePlanChangeResponse.status
@@ -489,9 +518,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -504,15 +542,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -558,8 +627,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -576,8 +653,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -632,8 +717,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -649,11 +741,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
         }
 
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
+        }
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -663,10 +772,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
+
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -678,7 +806,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -701,7 +843,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -740,11 +896,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -785,31 +958,55 @@ private constructor(
 
         fun build(): SubscriptionSchedulePlanChangeResponse =
             SubscriptionSchedulePlanChangeResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -850,20 +1047,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -891,18 +1094,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -918,6 +1122,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -925,11 +1144,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -963,11 +1200,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1270,11 +1510,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1282,12 +1522,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1295,15 +1535,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1333,13 +1573,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1347,7 +1587,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1387,7 +1628,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1405,9 +1660,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1415,7 +1679,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1444,13 +1711,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1582,16 +1860,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1599,7 +1877,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1607,15 +1885,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1645,13 +1923,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1659,7 +1937,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1685,7 +1966,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1718,9 +2013,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1728,7 +2032,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1757,13 +2064,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1894,16 +2212,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1911,21 +2229,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1955,20 +2275,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1994,7 +2315,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2012,9 +2347,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2022,7 +2366,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2066,13 +2413,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2209,16 +2567,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2226,24 +2584,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2274,21 +2634,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2314,7 +2675,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2353,9 +2728,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2363,7 +2747,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2392,14 +2779,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2530,16 +2928,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2547,21 +2945,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2591,20 +2991,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2629,7 +3030,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2662,9 +3077,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2672,7 +3096,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2701,13 +3128,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2840,19 +3278,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2878,7 +3316,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2913,7 +3351,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2925,7 +3376,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2954,7 +3418,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3206,25 +3670,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3253,19 +3725,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3288,7 +3762,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3298,9 +3786,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3309,7 +3812,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3346,12 +3852,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3474,25 +3988,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3521,18 +4041,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3547,7 +4071,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3557,9 +4095,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3568,7 +4121,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3618,12 +4174,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3749,26 +4313,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3797,18 +4369,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3822,7 +4396,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3832,9 +4420,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3843,7 +4446,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3895,12 +4501,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4004,13 +4618,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4037,10 +4655,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4052,7 +4670,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4091,10 +4711,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4164,24 +4784,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4209,17 +4835,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4232,7 +4859,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4242,11 +4883,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4294,11 +4953,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4448,24 +5113,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4493,17 +5164,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4516,7 +5188,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4526,11 +5212,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4578,11 +5282,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4917,10 +5627,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4929,7 +5641,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4938,13 +5650,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4952,7 +5667,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5182,13 +5898,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5219,15 +5937,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5237,7 +5956,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5261,8 +5981,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5278,8 +6006,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5294,7 +6031,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5307,8 +6050,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5316,7 +6067,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5778,6 +6551,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5813,14 +6651,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5848,11 +6695,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5878,9 +6727,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5931,9 +6780,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5998,11 +6849,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6028,9 +6883,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6045,7 +6900,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6076,9 +6933,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6178,7 +7035,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6202,7 +7061,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6211,7 +7070,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6234,7 +7095,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseParams.kt
index eb5a43ca..e0c387cb 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -17,6 +19,7 @@ import java.time.LocalDate
 import java.util.Objects
 import java.util.Optional
 
+/** Manually trigger a phase, effective the given date (or the current time, if not specified). */
 class SubscriptionTriggerPhaseParams
 constructor(
     private val subscriptionId: String,
@@ -33,12 +36,18 @@ constructor(
      */
     fun effectiveDate(): Optional<LocalDate> = body.effectiveDate()
 
+    /**
+     * The date on which the phase change should take effect. If not provided, defaults to today in
+     * the customer's timezone.
+     */
+    fun _effectiveDate(): JsonField<LocalDate> = body._effectiveDate()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): SubscriptionTriggerPhaseBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -56,22 +65,41 @@ constructor(
     class SubscriptionTriggerPhaseBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("effective_date") private val effectiveDate: LocalDate?,
+        @JsonProperty("effective_date")
+        @ExcludeMissing
+        private val effectiveDate: JsonField<LocalDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * The date on which the phase change should take effect. If not provided, defaults to today
+         * in the customer's timezone.
+         */
+        fun effectiveDate(): Optional<LocalDate> =
+            Optional.ofNullable(effectiveDate.getNullable("effective_date"))
+
         /**
          * The date on which the phase change should take effect. If not provided, defaults to today
          * in the customer's timezone.
          */
         @JsonProperty("effective_date")
-        fun effectiveDate(): Optional<LocalDate> = Optional.ofNullable(effectiveDate)
+        @ExcludeMissing
+        fun _effectiveDate(): JsonField<LocalDate> = effectiveDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionTriggerPhaseBody = apply {
+            if (!validated) {
+                effectiveDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -81,7 +109,7 @@ constructor(
 
         class Builder {
 
-            private var effectiveDate: LocalDate? = null
+            private var effectiveDate: JsonField<LocalDate> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -95,9 +123,8 @@ constructor(
              * The date on which the phase change should take effect. If not provided, defaults to
              * today in the customer's timezone.
              */
-            fun effectiveDate(effectiveDate: LocalDate?) = apply {
-                this.effectiveDate = effectiveDate
-            }
+            fun effectiveDate(effectiveDate: LocalDate?) =
+                effectiveDate(JsonField.ofNullable(effectiveDate))
 
             /**
              * The date on which the phase change should take effect. If not provided, defaults to
@@ -106,6 +133,14 @@ constructor(
             fun effectiveDate(effectiveDate: Optional<LocalDate>) =
                 effectiveDate(effectiveDate.orElse(null))
 
+            /**
+             * The date on which the phase change should take effect. If not provided, defaults to
+             * today in the customer's timezone.
+             */
+            fun effectiveDate(effectiveDate: JsonField<LocalDate>) = apply {
+                this.effectiveDate = effectiveDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -186,6 +221,33 @@ constructor(
         fun effectiveDate(effectiveDate: Optional<LocalDate>) =
             effectiveDate(effectiveDate.orElse(null))
 
+        /**
+         * The date on which the phase change should take effect. If not provided, defaults to today
+         * in the customer's timezone.
+         */
+        fun effectiveDate(effectiveDate: JsonField<LocalDate>) = apply {
+            body.effectiveDate(effectiveDate)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -284,25 +346,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionTriggerPhaseParams =
             SubscriptionTriggerPhaseParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseResponse.kt
index 7d9d66b5..36b884f4 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionTriggerPhaseResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -453,7 +473,8 @@ private constructor(
             apply {
                 id = subscriptionTriggerPhaseResponse.id
                 activePlanPhaseOrder = subscriptionTriggerPhaseResponse.activePlanPhaseOrder
-                adjustmentIntervals = subscriptionTriggerPhaseResponse.adjustmentIntervals
+                adjustmentIntervals =
+                    subscriptionTriggerPhaseResponse.adjustmentIntervals.map { it.toMutableList() }
                 autoCollection = subscriptionTriggerPhaseResponse.autoCollection
                 billingCycleAnchorConfiguration =
                     subscriptionTriggerPhaseResponse.billingCycleAnchorConfiguration
@@ -465,16 +486,23 @@ private constructor(
                     subscriptionTriggerPhaseResponse.currentBillingPeriodStartDate
                 customer = subscriptionTriggerPhaseResponse.customer
                 defaultInvoiceMemo = subscriptionTriggerPhaseResponse.defaultInvoiceMemo
-                discountIntervals = subscriptionTriggerPhaseResponse.discountIntervals
+                discountIntervals =
+                    subscriptionTriggerPhaseResponse.discountIntervals.map { it.toMutableList() }
                 endDate = subscriptionTriggerPhaseResponse.endDate
-                fixedFeeQuantitySchedule = subscriptionTriggerPhaseResponse.fixedFeeQuantitySchedule
+                fixedFeeQuantitySchedule =
+                    subscriptionTriggerPhaseResponse.fixedFeeQuantitySchedule.map {
+                        it.toMutableList()
+                    }
                 invoicingThreshold = subscriptionTriggerPhaseResponse.invoicingThreshold
-                maximumIntervals = subscriptionTriggerPhaseResponse.maximumIntervals
+                maximumIntervals =
+                    subscriptionTriggerPhaseResponse.maximumIntervals.map { it.toMutableList() }
                 metadata = subscriptionTriggerPhaseResponse.metadata
-                minimumIntervals = subscriptionTriggerPhaseResponse.minimumIntervals
+                minimumIntervals =
+                    subscriptionTriggerPhaseResponse.minimumIntervals.map { it.toMutableList() }
                 netTerms = subscriptionTriggerPhaseResponse.netTerms
                 plan = subscriptionTriggerPhaseResponse.plan
-                priceIntervals = subscriptionTriggerPhaseResponse.priceIntervals
+                priceIntervals =
+                    subscriptionTriggerPhaseResponse.priceIntervals.map { it.toMutableList() }
                 redeemedCoupon = subscriptionTriggerPhaseResponse.redeemedCoupon
                 startDate = subscriptionTriggerPhaseResponse.startDate
                 status = subscriptionTriggerPhaseResponse.status
@@ -487,9 +515,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -502,15 +539,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -556,8 +624,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -574,8 +650,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -630,8 +714,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -647,11 +738,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -661,10 +769,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -676,7 +803,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -699,7 +840,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -738,11 +893,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -783,31 +955,55 @@ private constructor(
 
         fun build(): SubscriptionTriggerPhaseResponse =
             SubscriptionTriggerPhaseResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -848,20 +1044,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -889,18 +1091,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -916,6 +1119,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -923,11 +1141,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -961,11 +1197,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1268,11 +1507,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1280,12 +1519,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1293,15 +1532,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1331,13 +1570,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1345,7 +1584,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1385,7 +1625,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1403,9 +1657,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1413,7 +1676,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1442,13 +1708,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1580,16 +1857,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1597,7 +1874,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1605,15 +1882,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1643,13 +1920,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1657,7 +1934,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1683,7 +1963,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1716,9 +2010,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1726,7 +2029,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1755,13 +2061,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1892,16 +2209,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1909,21 +2226,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1953,20 +2272,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1992,7 +2312,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2010,9 +2344,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2020,7 +2363,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2064,13 +2410,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2207,16 +2564,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2224,24 +2581,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2272,21 +2631,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2312,7 +2672,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2351,9 +2725,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2361,7 +2744,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2390,14 +2776,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2528,16 +2925,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2545,21 +2942,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2589,20 +2988,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2627,7 +3027,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2660,9 +3074,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2670,7 +3093,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2699,13 +3125,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2838,19 +3275,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2876,7 +3313,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2911,7 +3348,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2923,7 +3373,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2952,7 +3415,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3204,25 +3667,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3251,19 +3722,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3286,7 +3759,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3296,9 +3783,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3307,7 +3809,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3344,12 +3849,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3472,25 +3985,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3519,18 +4038,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3545,7 +4068,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3555,9 +4092,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3566,7 +4118,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3616,12 +4171,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3747,26 +4310,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3795,18 +4366,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3820,7 +4393,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3830,9 +4417,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3841,7 +4443,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3893,12 +4498,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4002,13 +4615,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4035,10 +4652,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4050,7 +4667,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4089,10 +4708,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4162,24 +4781,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4207,17 +4832,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4230,7 +4856,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4240,11 +4880,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4292,11 +4950,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4446,24 +5110,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4491,17 +5161,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4514,7 +5185,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4524,11 +5209,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4576,11 +5279,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4915,10 +5624,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4927,7 +5638,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4936,13 +5647,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4950,7 +5664,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5180,13 +5895,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5217,15 +5934,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5235,7 +5953,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5259,8 +5978,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5276,8 +6003,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5292,7 +6028,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5305,8 +6047,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5314,7 +6064,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5776,6 +6548,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5811,14 +6648,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5846,11 +6692,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5876,9 +6724,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5929,9 +6777,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5996,11 +6846,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6026,9 +6880,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6043,7 +6897,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6074,9 +6930,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6176,7 +7032,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6200,7 +7058,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6209,7 +7067,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6232,7 +7092,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationParams.kt
index f9b83ee5..1d53f0d0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationParams.kt
@@ -10,6 +10,13 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to unschedule any pending cancellations for a subscription.
+ *
+ * To be eligible, the subscription must currently be active and have a future cancellation. This
+ * operation will turn on auto-renew, ensuring that the subscription does not end at the currently
+ * scheduled cancellation time.
+ */
 class SubscriptionUnscheduleCancellationParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationResponse.kt
index 005309db..6f56f3ea 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleCancellationResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -454,7 +474,10 @@ private constructor(
         ) = apply {
             id = subscriptionUnscheduleCancellationResponse.id
             activePlanPhaseOrder = subscriptionUnscheduleCancellationResponse.activePlanPhaseOrder
-            adjustmentIntervals = subscriptionUnscheduleCancellationResponse.adjustmentIntervals
+            adjustmentIntervals =
+                subscriptionUnscheduleCancellationResponse.adjustmentIntervals.map {
+                    it.toMutableList()
+                }
             autoCollection = subscriptionUnscheduleCancellationResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionUnscheduleCancellationResponse.billingCycleAnchorConfiguration
@@ -466,17 +489,29 @@ private constructor(
                 subscriptionUnscheduleCancellationResponse.currentBillingPeriodStartDate
             customer = subscriptionUnscheduleCancellationResponse.customer
             defaultInvoiceMemo = subscriptionUnscheduleCancellationResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionUnscheduleCancellationResponse.discountIntervals
+            discountIntervals =
+                subscriptionUnscheduleCancellationResponse.discountIntervals.map {
+                    it.toMutableList()
+                }
             endDate = subscriptionUnscheduleCancellationResponse.endDate
             fixedFeeQuantitySchedule =
-                subscriptionUnscheduleCancellationResponse.fixedFeeQuantitySchedule
+                subscriptionUnscheduleCancellationResponse.fixedFeeQuantitySchedule.map {
+                    it.toMutableList()
+                }
             invoicingThreshold = subscriptionUnscheduleCancellationResponse.invoicingThreshold
-            maximumIntervals = subscriptionUnscheduleCancellationResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionUnscheduleCancellationResponse.maximumIntervals.map {
+                    it.toMutableList()
+                }
             metadata = subscriptionUnscheduleCancellationResponse.metadata
-            minimumIntervals = subscriptionUnscheduleCancellationResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionUnscheduleCancellationResponse.minimumIntervals.map {
+                    it.toMutableList()
+                }
             netTerms = subscriptionUnscheduleCancellationResponse.netTerms
             plan = subscriptionUnscheduleCancellationResponse.plan
-            priceIntervals = subscriptionUnscheduleCancellationResponse.priceIntervals
+            priceIntervals =
+                subscriptionUnscheduleCancellationResponse.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscriptionUnscheduleCancellationResponse.redeemedCoupon
             startDate = subscriptionUnscheduleCancellationResponse.startDate
             status = subscriptionUnscheduleCancellationResponse.status
@@ -489,9 +524,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -504,7 +548,21 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
+        }
+
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
         }
 
         /**
@@ -512,7 +570,24 @@ private constructor(
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -558,8 +633,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -576,8 +659,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -632,8 +723,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -649,11 +747,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -663,10 +778,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
+
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -678,7 +812,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -701,7 +849,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -740,11 +902,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
+        }
+
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -785,31 +964,55 @@ private constructor(
 
         fun build(): SubscriptionUnscheduleCancellationResponse =
             SubscriptionUnscheduleCancellationResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -850,20 +1053,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -891,18 +1100,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -918,6 +1128,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -925,11 +1150,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -963,11 +1206,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1270,11 +1516,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1282,12 +1528,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1295,15 +1541,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1333,13 +1579,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1347,7 +1593,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1387,7 +1634,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1405,9 +1666,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1415,7 +1685,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1444,13 +1717,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1582,16 +1866,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1599,7 +1883,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1607,15 +1891,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1645,13 +1929,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1659,7 +1943,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1685,7 +1972,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1718,9 +2019,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1728,7 +2038,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1757,13 +2070,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1894,16 +2218,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1911,21 +2235,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1955,20 +2281,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1994,7 +2321,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2012,9 +2353,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2022,7 +2372,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2066,13 +2419,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2209,16 +2573,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2226,24 +2590,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2274,21 +2640,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2314,7 +2681,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2353,9 +2734,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2363,7 +2753,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2392,14 +2785,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2530,16 +2934,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2547,21 +2951,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2591,20 +2997,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2629,7 +3036,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2662,9 +3083,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2672,7 +3102,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2701,13 +3134,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2840,19 +3284,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2878,7 +3322,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2913,7 +3357,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2925,7 +3382,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2954,7 +3424,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3206,25 +3676,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3253,19 +3731,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3288,7 +3768,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3298,9 +3792,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3309,7 +3818,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3346,12 +3858,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3474,25 +3994,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3521,18 +4047,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3547,7 +4077,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3557,9 +4101,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3568,7 +4127,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3618,12 +4180,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3749,26 +4319,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3797,18 +4375,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3822,7 +4402,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3832,9 +4426,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3843,7 +4452,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3895,12 +4507,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4004,13 +4624,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4037,10 +4661,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4052,7 +4676,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4091,10 +4717,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4164,24 +4790,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4209,17 +4841,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4232,7 +4865,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4242,11 +4889,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4294,11 +4959,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4448,24 +5119,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4493,17 +5170,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4516,7 +5194,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4526,11 +5218,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4578,11 +5288,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4917,10 +5633,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4929,7 +5647,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4938,13 +5656,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4952,7 +5673,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5182,13 +5904,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5219,15 +5943,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5237,7 +5962,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5261,8 +5987,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5278,8 +6012,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5294,7 +6037,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5307,8 +6056,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5316,7 +6073,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5778,6 +6557,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5813,14 +6657,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5848,11 +6701,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5878,9 +6733,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5931,9 +6786,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5998,11 +6855,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6028,9 +6889,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6045,7 +6906,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6076,9 +6939,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6178,7 +7041,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6202,7 +7067,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6211,7 +7076,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6234,7 +7101,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesParams.kt
index 9a5e8b0a..5731bee7 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -15,6 +17,12 @@ import com.withorb.api.core.immutableEmptyMap
 import com.withorb.api.core.toImmutable
 import java.util.Objects
 
+/**
+ * This endpoint can be used to clear scheduled updates to the quantity for a fixed fee.
+ *
+ * If there are no updates scheduled, a request validation error will be returned with a 400 status
+ * code.
+ */
 class SubscriptionUnscheduleFixedFeeQuantityUpdatesParams
 constructor(
     private val subscriptionId: String,
@@ -28,12 +36,15 @@ constructor(
     /** Price for which the updates should be cleared. Must be a fixed fee. */
     fun priceId(): String = body.priceId()
 
+    /** Price for which the updates should be cleared. Must be a fixed fee. */
+    fun _priceId(): JsonField<String> = body._priceId()
+
+    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
+
     fun _additionalHeaders(): Headers = additionalHeaders
 
     fun _additionalQueryParams(): QueryParams = additionalQueryParams
 
-    fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
-
     @JvmSynthetic internal fun getBody(): SubscriptionUnscheduleFixedFeeQuantityUpdatesBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -51,18 +62,32 @@ constructor(
     class SubscriptionUnscheduleFixedFeeQuantityUpdatesBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("price_id") private val priceId: String,
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** Price for which the updates should be cleared. Must be a fixed fee. */
-        @JsonProperty("price_id") fun priceId(): String = priceId
+        fun priceId(): String = priceId.getRequired("price_id")
+
+        /** Price for which the updates should be cleared. Must be a fixed fee. */
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionUnscheduleFixedFeeQuantityUpdatesBody = apply {
+            if (!validated) {
+                priceId()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -72,7 +97,7 @@ constructor(
 
         class Builder {
 
-            private var priceId: String? = null
+            private var priceId: JsonField<String>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -87,7 +112,10 @@ constructor(
             }
 
             /** Price for which the updates should be cleared. Must be a fixed fee. */
-            fun priceId(priceId: String) = apply { this.priceId = priceId }
+            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+
+            /** Price for which the updates should be cleared. Must be a fixed fee. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -168,6 +196,28 @@ constructor(
         /** Price for which the updates should be cleared. Must be a fixed fee. */
         fun priceId(priceId: String) = apply { body.priceId(priceId) }
 
+        /** Price for which the updates should be cleared. Must be a fixed fee. */
+        fun priceId(priceId: JsonField<String>) = apply { body.priceId(priceId) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -266,25 +316,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionUnscheduleFixedFeeQuantityUpdatesParams =
             SubscriptionUnscheduleFixedFeeQuantityUpdatesParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse.kt
index f8edcee5..0b982576 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -457,7 +477,9 @@ private constructor(
             activePlanPhaseOrder =
                 subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.activePlanPhaseOrder
             adjustmentIntervals =
-                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.adjustmentIntervals
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.adjustmentIntervals.map {
+                    it.toMutableList()
+                }
             autoCollection = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionUnscheduleFixedFeeQuantityUpdatesResponse
@@ -472,20 +494,31 @@ private constructor(
             defaultInvoiceMemo =
                 subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.defaultInvoiceMemo
             discountIntervals =
-                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.discountIntervals
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.discountIntervals.map {
+                    it.toMutableList()
+                }
             endDate = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.endDate
             fixedFeeQuantitySchedule =
-                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.fixedFeeQuantitySchedule
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.fixedFeeQuantitySchedule.map {
+                    it.toMutableList()
+                }
             invoicingThreshold =
                 subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.invoicingThreshold
             maximumIntervals =
-                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.maximumIntervals
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.maximumIntervals.map {
+                    it.toMutableList()
+                }
             metadata = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.metadata
             minimumIntervals =
-                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.minimumIntervals
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.minimumIntervals.map {
+                    it.toMutableList()
+                }
             netTerms = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.netTerms
             plan = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.plan
-            priceIntervals = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.priceIntervals
+            priceIntervals =
+                subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.priceIntervals.map {
+                    it.toMutableList()
+                }
             redeemedCoupon = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.redeemedCoupon
             startDate = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.startDate
             status = subscriptionUnscheduleFixedFeeQuantityUpdatesResponse.status
@@ -499,9 +532,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -514,7 +556,21 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
+        }
+
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
         }
 
         /**
@@ -522,7 +578,24 @@ private constructor(
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -568,8 +641,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -586,8 +667,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -642,8 +731,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -659,11 +755,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -673,10 +786,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -688,7 +820,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -711,7 +857,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -750,11 +910,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -795,31 +972,55 @@ private constructor(
 
         fun build(): SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse =
             SubscriptionUnscheduleFixedFeeQuantityUpdatesResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -860,20 +1061,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -901,18 +1108,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -928,6 +1136,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -935,11 +1158,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -973,11 +1214,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1280,11 +1524,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1292,12 +1536,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1305,15 +1549,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1343,13 +1587,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1357,7 +1601,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1397,7 +1642,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1415,9 +1674,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1425,7 +1693,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1454,13 +1725,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1592,16 +1874,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1609,7 +1891,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1617,15 +1899,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1655,13 +1937,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1669,7 +1951,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1695,7 +1980,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1728,9 +2027,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1738,7 +2046,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1767,13 +2078,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1904,16 +2226,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1921,21 +2243,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1965,20 +2289,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -2004,7 +2329,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2022,9 +2361,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2032,7 +2380,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2076,13 +2427,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2219,16 +2581,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2236,24 +2598,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2284,21 +2648,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2324,7 +2689,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2363,9 +2742,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2373,7 +2761,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2402,14 +2793,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2540,16 +2942,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2557,21 +2959,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2601,20 +3005,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2639,7 +3044,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2672,9 +3091,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2682,7 +3110,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2711,13 +3142,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2850,19 +3292,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2888,7 +3330,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2923,7 +3365,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2935,7 +3390,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2964,7 +3432,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3216,25 +3684,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3263,19 +3739,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3298,7 +3776,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3308,9 +3800,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3319,7 +3826,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3356,12 +3866,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3484,25 +4002,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3531,18 +4055,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3557,7 +4085,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3567,9 +4109,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3578,7 +4135,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3628,12 +4188,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3759,26 +4327,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3807,18 +4383,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3832,7 +4410,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3842,9 +4434,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3853,7 +4460,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3905,12 +4515,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4014,13 +4632,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4047,10 +4669,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4062,7 +4684,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4101,10 +4725,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4174,24 +4798,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4219,17 +4849,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4242,7 +4873,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4252,11 +4897,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4304,11 +4967,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4458,24 +5127,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4503,17 +5178,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4526,7 +5202,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4536,11 +5226,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4588,11 +5296,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4927,10 +5641,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4939,7 +5655,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4948,13 +5664,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4962,7 +5681,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5192,13 +5912,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5229,15 +5951,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5247,7 +5970,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5271,8 +5995,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5288,8 +6020,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5304,7 +6045,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5317,8 +6064,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5326,7 +6081,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5788,6 +6565,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5823,14 +6665,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5858,11 +6709,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5888,9 +6741,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5941,9 +6794,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6008,11 +6863,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6038,9 +6897,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6055,7 +6914,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6086,9 +6947,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6188,7 +7049,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6212,7 +7075,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6221,7 +7084,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6244,7 +7109,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesParams.kt
index 7de0a3cc..0a042357 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesParams.kt
@@ -10,6 +10,7 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/** This endpoint can be used to unschedule any pending plan changes on an existing subscription. */
 class SubscriptionUnschedulePendingPlanChangesParams
 constructor(
     private val subscriptionId: String,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesResponse.kt
index ce81da9f..680a0b26 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUnschedulePendingPlanChangesResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -457,7 +477,9 @@ private constructor(
             activePlanPhaseOrder =
                 subscriptionUnschedulePendingPlanChangesResponse.activePlanPhaseOrder
             adjustmentIntervals =
-                subscriptionUnschedulePendingPlanChangesResponse.adjustmentIntervals
+                subscriptionUnschedulePendingPlanChangesResponse.adjustmentIntervals.map {
+                    it.toMutableList()
+                }
             autoCollection = subscriptionUnschedulePendingPlanChangesResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionUnschedulePendingPlanChangesResponse.billingCycleAnchorConfiguration
@@ -469,17 +491,31 @@ private constructor(
                 subscriptionUnschedulePendingPlanChangesResponse.currentBillingPeriodStartDate
             customer = subscriptionUnschedulePendingPlanChangesResponse.customer
             defaultInvoiceMemo = subscriptionUnschedulePendingPlanChangesResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionUnschedulePendingPlanChangesResponse.discountIntervals
+            discountIntervals =
+                subscriptionUnschedulePendingPlanChangesResponse.discountIntervals.map {
+                    it.toMutableList()
+                }
             endDate = subscriptionUnschedulePendingPlanChangesResponse.endDate
             fixedFeeQuantitySchedule =
-                subscriptionUnschedulePendingPlanChangesResponse.fixedFeeQuantitySchedule
+                subscriptionUnschedulePendingPlanChangesResponse.fixedFeeQuantitySchedule.map {
+                    it.toMutableList()
+                }
             invoicingThreshold = subscriptionUnschedulePendingPlanChangesResponse.invoicingThreshold
-            maximumIntervals = subscriptionUnschedulePendingPlanChangesResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionUnschedulePendingPlanChangesResponse.maximumIntervals.map {
+                    it.toMutableList()
+                }
             metadata = subscriptionUnschedulePendingPlanChangesResponse.metadata
-            minimumIntervals = subscriptionUnschedulePendingPlanChangesResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionUnschedulePendingPlanChangesResponse.minimumIntervals.map {
+                    it.toMutableList()
+                }
             netTerms = subscriptionUnschedulePendingPlanChangesResponse.netTerms
             plan = subscriptionUnschedulePendingPlanChangesResponse.plan
-            priceIntervals = subscriptionUnschedulePendingPlanChangesResponse.priceIntervals
+            priceIntervals =
+                subscriptionUnschedulePendingPlanChangesResponse.priceIntervals.map {
+                    it.toMutableList()
+                }
             redeemedCoupon = subscriptionUnschedulePendingPlanChangesResponse.redeemedCoupon
             startDate = subscriptionUnschedulePendingPlanChangesResponse.startDate
             status = subscriptionUnschedulePendingPlanChangesResponse.status
@@ -492,9 +528,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -507,7 +552,21 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
+        }
+
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
         }
 
         /**
@@ -515,7 +574,24 @@ private constructor(
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -561,8 +637,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -579,8 +663,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -635,8 +727,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -652,11 +751,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
         }
 
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
+        }
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -666,10 +782,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
+
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -681,7 +816,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -704,7 +853,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -743,11 +906,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -788,31 +968,55 @@ private constructor(
 
         fun build(): SubscriptionUnschedulePendingPlanChangesResponse =
             SubscriptionUnschedulePendingPlanChangesResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -853,20 +1057,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -894,18 +1104,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -921,6 +1132,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -928,11 +1154,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -966,11 +1210,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1273,11 +1520,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1285,12 +1532,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1298,15 +1545,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1336,13 +1583,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1350,7 +1597,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1390,7 +1638,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1408,9 +1670,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1418,7 +1689,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1447,13 +1721,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1585,16 +1870,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1602,7 +1887,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1610,15 +1895,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1648,13 +1933,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1662,7 +1947,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1688,7 +1976,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1721,9 +2023,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1731,7 +2042,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1760,13 +2074,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1897,16 +2222,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1914,21 +2239,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1958,20 +2285,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1997,7 +2325,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2015,9 +2357,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2025,7 +2376,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2069,13 +2423,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2212,16 +2577,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2229,24 +2594,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2277,21 +2644,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2317,7 +2685,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2356,9 +2738,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2366,7 +2757,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2395,14 +2789,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2533,16 +2938,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2550,21 +2955,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2594,20 +3001,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2632,7 +3040,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2665,9 +3087,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2675,7 +3106,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2704,13 +3138,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2843,19 +3288,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2881,7 +3326,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2916,7 +3361,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2928,7 +3386,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2957,7 +3428,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3209,25 +3680,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3256,19 +3735,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3291,7 +3772,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3301,9 +3796,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3312,7 +3822,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3349,12 +3862,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3477,25 +3998,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3524,18 +4051,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3550,7 +4081,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3560,9 +4105,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3571,7 +4131,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3621,12 +4184,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3752,26 +4323,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3800,18 +4379,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3825,7 +4406,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3835,9 +4430,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3846,7 +4456,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3898,12 +4511,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4007,13 +4628,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4040,10 +4665,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4055,7 +4680,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4094,10 +4721,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4167,24 +4794,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4212,17 +4845,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4235,7 +4869,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4245,11 +4893,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4297,11 +4963,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4451,24 +5123,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4496,17 +5174,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4519,7 +5198,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4529,11 +5222,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4581,11 +5292,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4920,10 +5637,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4932,7 +5651,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4941,13 +5660,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4955,7 +5677,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5185,13 +5908,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5222,15 +5947,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5240,7 +5966,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5264,8 +5991,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5281,8 +6016,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5297,7 +6041,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5310,8 +6060,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5319,7 +6077,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5781,6 +6561,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5816,14 +6661,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5851,11 +6705,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5881,9 +6737,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5934,9 +6790,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -6001,11 +6859,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6031,9 +6893,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6048,7 +6910,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6079,9 +6943,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6181,7 +7045,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6205,7 +7071,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6214,7 +7080,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6237,7 +7105,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityParams.kt
index 46513293..72967d56 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityParams.kt
@@ -9,6 +9,7 @@ import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -20,6 +21,20 @@ import java.time.LocalDate
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to update the quantity for a fixed fee.
+ *
+ * To be eligible, the subscription must currently be active and the price specified must be a fixed
+ * fee (not usage-based). This operation will immediately update the quantity for the fee, or if a
+ * `effective_date` is passed in, will update the quantity on the requested date at midnight in the
+ * customer's timezone.
+ *
+ * In order to change the fixed fee quantity as of the next draft invoice for this subscription,
+ * pass `change_option=upcoming_invoice` without an `effective_date` specified.
+ *
+ * If the fee is an in-advance fixed fee, it will also issue an immediate invoice for the difference
+ * for the remainder of the billing period.
+ */
 class SubscriptionUpdateFixedFeeQuantityParams
 constructor(
     private val subscriptionId: String,
@@ -49,12 +64,31 @@ constructor(
      */
     fun effectiveDate(): Optional<LocalDate> = body.effectiveDate()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /** Price for which the quantity should be updated. Must be a fixed fee. */
+    fun _priceId(): JsonField<String> = body._priceId()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    fun _quantity(): JsonField<Double> = body._quantity()
+
+    /**
+     * Determines when the change takes effect. Note that if `effective_date` is specified, this
+     * defaults to `effective_date`. Otherwise, this defaults to `immediate` unless it's explicitly
+     * set to `upcoming_invoice.
+     */
+    fun _changeOption(): JsonField<ChangeOption> = body._changeOption()
+
+    /**
+     * The date that the quantity change should take effect, localized to the customer's timezone.
+     * Ifthis parameter is not passed in, the quantity change is effective according to
+     * `change_option`.
+     */
+    fun _effectiveDate(): JsonField<LocalDate> = body._effectiveDate()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionUpdateFixedFeeQuantityBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -72,18 +106,47 @@ constructor(
     class SubscriptionUpdateFixedFeeQuantityBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("price_id") private val priceId: String,
-        @JsonProperty("quantity") private val quantity: Double,
-        @JsonProperty("change_option") private val changeOption: ChangeOption?,
-        @JsonProperty("effective_date") private val effectiveDate: LocalDate?,
+        @JsonProperty("price_id")
+        @ExcludeMissing
+        private val priceId: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("quantity")
+        @ExcludeMissing
+        private val quantity: JsonField<Double> = JsonMissing.of(),
+        @JsonProperty("change_option")
+        @ExcludeMissing
+        private val changeOption: JsonField<ChangeOption> = JsonMissing.of(),
+        @JsonProperty("effective_date")
+        @ExcludeMissing
+        private val effectiveDate: JsonField<LocalDate> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
         /** Price for which the quantity should be updated. Must be a fixed fee. */
-        @JsonProperty("price_id") fun priceId(): String = priceId
+        fun priceId(): String = priceId.getRequired("price_id")
+
+        fun quantity(): Double = quantity.getRequired("quantity")
+
+        /**
+         * Determines when the change takes effect. Note that if `effective_date` is specified, this
+         * defaults to `effective_date`. Otherwise, this defaults to `immediate` unless it's
+         * explicitly set to `upcoming_invoice.
+         */
+        fun changeOption(): Optional<ChangeOption> =
+            Optional.ofNullable(changeOption.getNullable("change_option"))
+
+        /**
+         * The date that the quantity change should take effect, localized to the customer's
+         * timezone. Ifthis parameter is not passed in, the quantity change is effective according
+         * to `change_option`.
+         */
+        fun effectiveDate(): Optional<LocalDate> =
+            Optional.ofNullable(effectiveDate.getNullable("effective_date"))
+
+        /** Price for which the quantity should be updated. Must be a fixed fee. */
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") fun quantity(): Double = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
         /**
          * Determines when the change takes effect. Note that if `effective_date` is specified, this
@@ -91,7 +154,8 @@ constructor(
          * explicitly set to `upcoming_invoice.
          */
         @JsonProperty("change_option")
-        fun changeOption(): Optional<ChangeOption> = Optional.ofNullable(changeOption)
+        @ExcludeMissing
+        fun _changeOption(): JsonField<ChangeOption> = changeOption
 
         /**
          * The date that the quantity change should take effect, localized to the customer's
@@ -99,12 +163,25 @@ constructor(
          * to `change_option`.
          */
         @JsonProperty("effective_date")
-        fun effectiveDate(): Optional<LocalDate> = Optional.ofNullable(effectiveDate)
+        @ExcludeMissing
+        fun _effectiveDate(): JsonField<LocalDate> = effectiveDate
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionUpdateFixedFeeQuantityBody = apply {
+            if (!validated) {
+                priceId()
+                quantity()
+                changeOption()
+                effectiveDate()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -114,10 +191,10 @@ constructor(
 
         class Builder {
 
-            private var priceId: String? = null
-            private var quantity: Double? = null
-            private var changeOption: ChangeOption? = null
-            private var effectiveDate: LocalDate? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var changeOption: JsonField<ChangeOption> = JsonMissing.of()
+            private var effectiveDate: JsonField<LocalDate> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -133,35 +210,38 @@ constructor(
             }
 
             /** Price for which the quantity should be updated. Must be a fixed fee. */
-            fun priceId(priceId: String) = apply { this.priceId = priceId }
+            fun priceId(priceId: String) = priceId(JsonField.of(priceId))
+
+            /** Price for which the quantity should be updated. Must be a fixed fee. */
+            fun priceId(priceId: JsonField<String>) = apply { this.priceId = priceId }
+
+            fun quantity(quantity: Double) = quantity(JsonField.of(quantity))
 
-            fun quantity(quantity: Double) = apply { this.quantity = quantity }
+            fun quantity(quantity: JsonField<Double>) = apply { this.quantity = quantity }
 
             /**
              * Determines when the change takes effect. Note that if `effective_date` is specified,
              * this defaults to `effective_date`. Otherwise, this defaults to `immediate` unless
              * it's explicitly set to `upcoming_invoice.
              */
-            fun changeOption(changeOption: ChangeOption?) = apply {
-                this.changeOption = changeOption
-            }
+            fun changeOption(changeOption: ChangeOption) = changeOption(JsonField.of(changeOption))
 
             /**
              * Determines when the change takes effect. Note that if `effective_date` is specified,
              * this defaults to `effective_date`. Otherwise, this defaults to `immediate` unless
              * it's explicitly set to `upcoming_invoice.
              */
-            fun changeOption(changeOption: Optional<ChangeOption>) =
-                changeOption(changeOption.orElse(null))
+            fun changeOption(changeOption: JsonField<ChangeOption>) = apply {
+                this.changeOption = changeOption
+            }
 
             /**
              * The date that the quantity change should take effect, localized to the customer's
              * timezone. Ifthis parameter is not passed in, the quantity change is effective
              * according to `change_option`.
              */
-            fun effectiveDate(effectiveDate: LocalDate?) = apply {
-                this.effectiveDate = effectiveDate
-            }
+            fun effectiveDate(effectiveDate: LocalDate?) =
+                effectiveDate(JsonField.ofNullable(effectiveDate))
 
             /**
              * The date that the quantity change should take effect, localized to the customer's
@@ -171,6 +251,15 @@ constructor(
             fun effectiveDate(effectiveDate: Optional<LocalDate>) =
                 effectiveDate(effectiveDate.orElse(null))
 
+            /**
+             * The date that the quantity change should take effect, localized to the customer's
+             * timezone. Ifthis parameter is not passed in, the quantity change is effective
+             * according to `change_option`.
+             */
+            fun effectiveDate(effectiveDate: JsonField<LocalDate>) = apply {
+                this.effectiveDate = effectiveDate
+            }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -251,22 +340,28 @@ constructor(
         /** Price for which the quantity should be updated. Must be a fixed fee. */
         fun priceId(priceId: String) = apply { body.priceId(priceId) }
 
+        /** Price for which the quantity should be updated. Must be a fixed fee. */
+        fun priceId(priceId: JsonField<String>) = apply { body.priceId(priceId) }
+
         fun quantity(quantity: Double) = apply { body.quantity(quantity) }
 
+        fun quantity(quantity: JsonField<Double>) = apply { body.quantity(quantity) }
+
         /**
          * Determines when the change takes effect. Note that if `effective_date` is specified, this
          * defaults to `effective_date`. Otherwise, this defaults to `immediate` unless it's
          * explicitly set to `upcoming_invoice.
          */
-        fun changeOption(changeOption: ChangeOption?) = apply { body.changeOption(changeOption) }
+        fun changeOption(changeOption: ChangeOption) = apply { body.changeOption(changeOption) }
 
         /**
          * Determines when the change takes effect. Note that if `effective_date` is specified, this
          * defaults to `effective_date`. Otherwise, this defaults to `immediate` unless it's
          * explicitly set to `upcoming_invoice.
          */
-        fun changeOption(changeOption: Optional<ChangeOption>) =
-            changeOption(changeOption.orElse(null))
+        fun changeOption(changeOption: JsonField<ChangeOption>) = apply {
+            body.changeOption(changeOption)
+        }
 
         /**
          * The date that the quantity change should take effect, localized to the customer's
@@ -283,6 +378,34 @@ constructor(
         fun effectiveDate(effectiveDate: Optional<LocalDate>) =
             effectiveDate(effectiveDate.orElse(null))
 
+        /**
+         * The date that the quantity change should take effect, localized to the customer's
+         * timezone. Ifthis parameter is not passed in, the quantity change is effective according
+         * to `change_option`.
+         */
+        fun effectiveDate(effectiveDate: JsonField<LocalDate>) = apply {
+            body.effectiveDate(effectiveDate)
+        }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -381,25 +504,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionUpdateFixedFeeQuantityParams =
             SubscriptionUpdateFixedFeeQuantityParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityResponse.kt
index 0330da3e..8294bd5d 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateFixedFeeQuantityResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -454,7 +474,10 @@ private constructor(
         ) = apply {
             id = subscriptionUpdateFixedFeeQuantityResponse.id
             activePlanPhaseOrder = subscriptionUpdateFixedFeeQuantityResponse.activePlanPhaseOrder
-            adjustmentIntervals = subscriptionUpdateFixedFeeQuantityResponse.adjustmentIntervals
+            adjustmentIntervals =
+                subscriptionUpdateFixedFeeQuantityResponse.adjustmentIntervals.map {
+                    it.toMutableList()
+                }
             autoCollection = subscriptionUpdateFixedFeeQuantityResponse.autoCollection
             billingCycleAnchorConfiguration =
                 subscriptionUpdateFixedFeeQuantityResponse.billingCycleAnchorConfiguration
@@ -466,17 +489,29 @@ private constructor(
                 subscriptionUpdateFixedFeeQuantityResponse.currentBillingPeriodStartDate
             customer = subscriptionUpdateFixedFeeQuantityResponse.customer
             defaultInvoiceMemo = subscriptionUpdateFixedFeeQuantityResponse.defaultInvoiceMemo
-            discountIntervals = subscriptionUpdateFixedFeeQuantityResponse.discountIntervals
+            discountIntervals =
+                subscriptionUpdateFixedFeeQuantityResponse.discountIntervals.map {
+                    it.toMutableList()
+                }
             endDate = subscriptionUpdateFixedFeeQuantityResponse.endDate
             fixedFeeQuantitySchedule =
-                subscriptionUpdateFixedFeeQuantityResponse.fixedFeeQuantitySchedule
+                subscriptionUpdateFixedFeeQuantityResponse.fixedFeeQuantitySchedule.map {
+                    it.toMutableList()
+                }
             invoicingThreshold = subscriptionUpdateFixedFeeQuantityResponse.invoicingThreshold
-            maximumIntervals = subscriptionUpdateFixedFeeQuantityResponse.maximumIntervals
+            maximumIntervals =
+                subscriptionUpdateFixedFeeQuantityResponse.maximumIntervals.map {
+                    it.toMutableList()
+                }
             metadata = subscriptionUpdateFixedFeeQuantityResponse.metadata
-            minimumIntervals = subscriptionUpdateFixedFeeQuantityResponse.minimumIntervals
+            minimumIntervals =
+                subscriptionUpdateFixedFeeQuantityResponse.minimumIntervals.map {
+                    it.toMutableList()
+                }
             netTerms = subscriptionUpdateFixedFeeQuantityResponse.netTerms
             plan = subscriptionUpdateFixedFeeQuantityResponse.plan
-            priceIntervals = subscriptionUpdateFixedFeeQuantityResponse.priceIntervals
+            priceIntervals =
+                subscriptionUpdateFixedFeeQuantityResponse.priceIntervals.map { it.toMutableList() }
             redeemedCoupon = subscriptionUpdateFixedFeeQuantityResponse.redeemedCoupon
             startDate = subscriptionUpdateFixedFeeQuantityResponse.startDate
             status = subscriptionUpdateFixedFeeQuantityResponse.status
@@ -489,9 +524,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -504,7 +548,21 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
+        }
+
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
         }
 
         /**
@@ -512,7 +570,24 @@ private constructor(
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -558,8 +633,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -576,8 +659,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -632,8 +723,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -649,11 +747,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -663,10 +778,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
+
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -678,7 +812,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -701,7 +849,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -740,11 +902,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
+        }
+
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -785,31 +964,55 @@ private constructor(
 
         fun build(): SubscriptionUpdateFixedFeeQuantityResponse =
             SubscriptionUpdateFixedFeeQuantityResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -850,20 +1053,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -891,18 +1100,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -918,6 +1128,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -925,11 +1150,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -963,11 +1206,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1270,11 +1516,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1282,12 +1528,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1295,15 +1541,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1333,13 +1579,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1347,7 +1593,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1387,7 +1634,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1405,9 +1666,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1415,7 +1685,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1444,13 +1717,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1582,16 +1866,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1599,7 +1883,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1607,15 +1891,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1645,13 +1929,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1659,7 +1943,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1685,7 +1972,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1718,9 +2019,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1728,7 +2038,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1757,13 +2070,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1894,16 +2218,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1911,21 +2235,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1955,20 +2281,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1994,7 +2321,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2012,9 +2353,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2022,7 +2372,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2066,13 +2419,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2209,16 +2573,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2226,24 +2590,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2274,21 +2640,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2314,7 +2681,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2353,9 +2734,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2363,7 +2753,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2392,14 +2785,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2530,16 +2934,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2547,21 +2951,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2591,20 +2997,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2629,7 +3036,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2662,9 +3083,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2672,7 +3102,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2701,13 +3134,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2840,19 +3284,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2878,7 +3322,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2913,7 +3357,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2925,7 +3382,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2954,7 +3424,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3206,25 +3676,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3253,19 +3731,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3288,7 +3768,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3298,9 +3792,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3309,7 +3818,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3346,12 +3858,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3474,25 +3994,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3521,18 +4047,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3547,7 +4077,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3557,9 +4101,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3568,7 +4127,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3618,12 +4180,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3749,26 +4319,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3797,18 +4375,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3822,7 +4402,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3832,9 +4426,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3843,7 +4452,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3895,12 +4507,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4004,13 +4624,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4037,10 +4661,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4052,7 +4676,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4091,10 +4717,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4164,24 +4790,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4209,17 +4841,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4232,7 +4865,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4242,11 +4889,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4294,11 +4959,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4448,24 +5119,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4493,17 +5170,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4516,7 +5194,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4526,11 +5218,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4578,11 +5288,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4917,10 +5633,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4929,7 +5647,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4938,13 +5656,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4952,7 +5673,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5182,13 +5904,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5219,15 +5943,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5237,7 +5962,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5261,8 +5987,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5278,8 +6012,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5294,7 +6037,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5307,8 +6056,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5316,7 +6073,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5778,6 +6557,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5813,14 +6657,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5848,11 +6701,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5878,9 +6733,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5931,9 +6786,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5998,11 +6855,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6028,9 +6889,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6045,7 +6906,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6076,9 +6939,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6178,7 +7041,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6202,7 +7067,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6211,7 +7076,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6234,7 +7101,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateParams.kt
index 726c04e8..55969bad 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateParams.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.annotation.JsonAnySetter
 import com.fasterxml.jackson.annotation.JsonCreator
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.withorb.api.core.ExcludeMissing
+import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.http.Headers
@@ -16,6 +18,10 @@ import com.withorb.api.core.toImmutable
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint can be used to update the `metadata`, `net terms`, `auto_collection`,
+ * `invoicing_threshold`, and `default_invoice_memo` properties on a subscription.
+ */
 class SubscriptionUpdateParams
 constructor(
     private val subscriptionId: String,
@@ -59,12 +65,45 @@ constructor(
      */
     fun netTerms(): Optional<Long> = body.netTerms()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * Determines whether issued invoices for this subscription will automatically be charged with
+     * the saved payment method on the due date. This property defaults to the plan's behavior.
+     */
+    fun _autoCollection(): JsonField<Boolean> = body._autoCollection()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * Determines the default memo on this subscription's invoices. Note that if this is not
+     * provided, it is determined by the plan configuration.
+     */
+    fun _defaultInvoiceMemo(): JsonField<String> = body._defaultInvoiceMemo()
+
+    /**
+     * When this subscription's accrued usage reaches this threshold, an invoice will be issued for
+     * the subscription. If not specified, invoices will only be issued at the end of the billing
+     * period.
+     */
+    fun _invoicingThreshold(): JsonField<String> = body._invoicingThreshold()
+
+    /**
+     * User-specified key/value pairs for the resource. Individual keys can be removed by setting
+     * the value to `null`, and the entire metadata mapping can be cleared by setting `metadata` to
+     * `null`.
+     */
+    fun _metadata(): JsonField<Metadata> = body._metadata()
+
+    /**
+     * Determines the difference between the invoice issue date for subscription invoices as the
+     * date that they are due. A value of `0` here represents that the invoice is due on issue,
+     * whereas a value of `30` represents that the customer has a month to pay the invoice.
+     */
+    fun _netTerms(): JsonField<Long> = body._netTerms()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionUpdateBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -82,29 +121,78 @@ constructor(
     class SubscriptionUpdateBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("auto_collection") private val autoCollection: Boolean?,
-        @JsonProperty("default_invoice_memo") private val defaultInvoiceMemo: String?,
-        @JsonProperty("invoicing_threshold") private val invoicingThreshold: String?,
-        @JsonProperty("metadata") private val metadata: Metadata?,
-        @JsonProperty("net_terms") private val netTerms: Long?,
+        @JsonProperty("auto_collection")
+        @ExcludeMissing
+        private val autoCollection: JsonField<Boolean> = JsonMissing.of(),
+        @JsonProperty("default_invoice_memo")
+        @ExcludeMissing
+        private val defaultInvoiceMemo: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("invoicing_threshold")
+        @ExcludeMissing
+        private val invoicingThreshold: JsonField<String> = JsonMissing.of(),
+        @JsonProperty("metadata")
+        @ExcludeMissing
+        private val metadata: JsonField<Metadata> = JsonMissing.of(),
+        @JsonProperty("net_terms")
+        @ExcludeMissing
+        private val netTerms: JsonField<Long> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
 
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior.
+         */
+        fun autoCollection(): Optional<Boolean> =
+            Optional.ofNullable(autoCollection.getNullable("auto_collection"))
+
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(): Optional<String> =
+            Optional.ofNullable(defaultInvoiceMemo.getNullable("default_invoice_memo"))
+
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(): Optional<String> =
+            Optional.ofNullable(invoicingThreshold.getNullable("invoicing_threshold"))
+
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata.getNullable("metadata"))
+
+        /**
+         * Determines the difference between the invoice issue date for subscription invoices as the
+         * date that they are due. A value of `0` here represents that the invoice is due on issue,
+         * whereas a value of `30` represents that the customer has a month to pay the invoice.
+         */
+        fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms.getNullable("net_terms"))
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior.
          */
         @JsonProperty("auto_collection")
-        fun autoCollection(): Optional<Boolean> = Optional.ofNullable(autoCollection)
+        @ExcludeMissing
+        fun _autoCollection(): JsonField<Boolean> = autoCollection
 
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
         @JsonProperty("default_invoice_memo")
-        fun defaultInvoiceMemo(): Optional<String> = Optional.ofNullable(defaultInvoiceMemo)
+        @ExcludeMissing
+        fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
@@ -112,26 +200,40 @@ constructor(
          * billing period.
          */
         @JsonProperty("invoicing_threshold")
-        fun invoicingThreshold(): Optional<String> = Optional.ofNullable(invoicingThreshold)
+        @ExcludeMissing
+        fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
          * `metadata` to `null`.
          */
-        @JsonProperty("metadata") fun metadata(): Optional<Metadata> = Optional.ofNullable(metadata)
+        @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
         /**
          * Determines the difference between the invoice issue date for subscription invoices as the
          * date that they are due. A value of `0` here represents that the invoice is due on issue,
          * whereas a value of `30` represents that the customer has a month to pay the invoice.
          */
-        @JsonProperty("net_terms") fun netTerms(): Optional<Long> = Optional.ofNullable(netTerms)
+        @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionUpdateBody = apply {
+            if (!validated) {
+                autoCollection()
+                defaultInvoiceMemo()
+                invoicingThreshold()
+                metadata().map { it.validate() }
+                netTerms()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -141,11 +243,11 @@ constructor(
 
         class Builder {
 
-            private var autoCollection: Boolean? = null
-            private var defaultInvoiceMemo: String? = null
-            private var invoicingThreshold: String? = null
-            private var metadata: Metadata? = null
-            private var netTerms: Long? = null
+            private var autoCollection: JsonField<Boolean> = JsonMissing.of()
+            private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
+            private var invoicingThreshold: JsonField<String> = JsonMissing.of()
+            private var metadata: JsonField<Metadata> = JsonMissing.of()
+            private var netTerms: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -163,9 +265,8 @@ constructor(
              * charged with the saved payment method on the due date. This property defaults to the
              * plan's behavior.
              */
-            fun autoCollection(autoCollection: Boolean?) = apply {
-                this.autoCollection = autoCollection
-            }
+            fun autoCollection(autoCollection: Boolean?) =
+                autoCollection(JsonField.ofNullable(autoCollection))
 
             /**
              * Determines whether issued invoices for this subscription will automatically be
@@ -183,13 +284,21 @@ constructor(
             fun autoCollection(autoCollection: Optional<Boolean>) =
                 autoCollection(autoCollection.orElse(null) as Boolean?)
 
+            /**
+             * Determines whether issued invoices for this subscription will automatically be
+             * charged with the saved payment method on the due date. This property defaults to the
+             * plan's behavior.
+             */
+            fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+                this.autoCollection = autoCollection
+            }
+
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
              * provided, it is determined by the plan configuration.
              */
-            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) = apply {
-                this.defaultInvoiceMemo = defaultInvoiceMemo
-            }
+            fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+                defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
 
             /**
              * Determines the default memo on this subscription's invoices. Note that if this is not
@@ -198,14 +307,21 @@ constructor(
             fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
                 defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+            /**
+             * Determines the default memo on this subscription's invoices. Note that if this is not
+             * provided, it is determined by the plan configuration.
+             */
+            fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+                this.defaultInvoiceMemo = defaultInvoiceMemo
+            }
+
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
              * issued for the subscription. If not specified, invoices will only be issued at the
              * end of the billing period.
              */
-            fun invoicingThreshold(invoicingThreshold: String?) = apply {
-                this.invoicingThreshold = invoicingThreshold
-            }
+            fun invoicingThreshold(invoicingThreshold: String?) =
+                invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
 
             /**
              * When this subscription's accrued usage reaches this threshold, an invoice will be
@@ -215,12 +331,21 @@ constructor(
             fun invoicingThreshold(invoicingThreshold: Optional<String>) =
                 invoicingThreshold(invoicingThreshold.orElse(null))
 
+            /**
+             * When this subscription's accrued usage reaches this threshold, an invoice will be
+             * issued for the subscription. If not specified, invoices will only be issued at the
+             * end of the billing period.
+             */
+            fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+                this.invoicingThreshold = invoicingThreshold
+            }
+
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
              * setting the value to `null`, and the entire metadata mapping can be cleared by
              * setting `metadata` to `null`.
              */
-            fun metadata(metadata: Metadata?) = apply { this.metadata = metadata }
+            fun metadata(metadata: Metadata?) = metadata(JsonField.ofNullable(metadata))
 
             /**
              * User-specified key/value pairs for the resource. Individual keys can be removed by
@@ -229,13 +354,20 @@ constructor(
              */
             fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+            /**
+             * User-specified key/value pairs for the resource. Individual keys can be removed by
+             * setting the value to `null`, and the entire metadata mapping can be cleared by
+             * setting `metadata` to `null`.
+             */
+            fun metadata(metadata: JsonField<Metadata>) = apply { this.metadata = metadata }
+
             /**
              * Determines the difference between the invoice issue date for subscription invoices as
              * the date that they are due. A value of `0` here represents that the invoice is due on
              * issue, whereas a value of `30` represents that the customer has a month to pay the
              * invoice.
              */
-            fun netTerms(netTerms: Long?) = apply { this.netTerms = netTerms }
+            fun netTerms(netTerms: Long?) = netTerms(JsonField.ofNullable(netTerms))
 
             /**
              * Determines the difference between the invoice issue date for subscription invoices as
@@ -254,6 +386,14 @@ constructor(
             @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
             fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+            /**
+             * Determines the difference between the invoice issue date for subscription invoices as
+             * the date that they are due. A value of `0` here represents that the invoice is due on
+             * issue, whereas a value of `30` represents that the customer has a month to pay the
+             * invoice.
+             */
+            fun netTerms(netTerms: JsonField<Long>) = apply { this.netTerms = netTerms }
+
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
                 putAllAdditionalProperties(additionalProperties)
@@ -350,6 +490,15 @@ constructor(
         fun autoCollection(autoCollection: Optional<Boolean>) =
             autoCollection(autoCollection.orElse(null) as Boolean?)
 
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior.
+         */
+        fun autoCollection(autoCollection: JsonField<Boolean>) = apply {
+            body.autoCollection(autoCollection)
+        }
+
         /**
          * Determines the default memo on this subscription's invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
@@ -365,6 +514,14 @@ constructor(
         fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
             defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
+        /**
+         * Determines the default memo on this subscription's invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: JsonField<String>) = apply {
+            body.defaultInvoiceMemo(defaultInvoiceMemo)
+        }
+
         /**
          * When this subscription's accrued usage reaches this threshold, an invoice will be issued
          * for the subscription. If not specified, invoices will only be issued at the end of the
@@ -382,6 +539,15 @@ constructor(
         fun invoicingThreshold(invoicingThreshold: Optional<String>) =
             invoicingThreshold(invoicingThreshold.orElse(null))
 
+        /**
+         * When this subscription's accrued usage reaches this threshold, an invoice will be issued
+         * for the subscription. If not specified, invoices will only be issued at the end of the
+         * billing period.
+         */
+        fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
+            body.invoicingThreshold(invoicingThreshold)
+        }
+
         /**
          * User-specified key/value pairs for the resource. Individual keys can be removed by
          * setting the value to `null`, and the entire metadata mapping can be cleared by setting
@@ -396,6 +562,13 @@ constructor(
          */
         fun metadata(metadata: Optional<Metadata>) = metadata(metadata.orElse(null))
 
+        /**
+         * User-specified key/value pairs for the resource. Individual keys can be removed by
+         * setting the value to `null`, and the entire metadata mapping can be cleared by setting
+         * `metadata` to `null`.
+         */
+        fun metadata(metadata: JsonField<Metadata>) = apply { body.metadata(metadata) }
+
         /**
          * Determines the difference between the invoice issue date for subscription invoices as the
          * date that they are due. A value of `0` here represents that the invoice is due on issue,
@@ -418,6 +591,32 @@ constructor(
         @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
         fun netTerms(netTerms: Optional<Long>) = netTerms(netTerms.orElse(null) as Long?)
 
+        /**
+         * Determines the difference between the invoice issue date for subscription invoices as the
+         * date that they are due. A value of `0` here represents that the invoice is due on issue,
+         * whereas a value of `30` represents that the customer has a month to pay the invoice.
+         */
+        fun netTerms(netTerms: JsonField<Long>) = apply { body.netTerms(netTerms) }
+
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
+
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
             putAllAdditionalHeaders(additionalHeaders)
@@ -516,25 +715,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionUpdateParams =
             SubscriptionUpdateParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
@@ -561,6 +741,14 @@ constructor(
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): Metadata = apply {
+            if (!validated) {
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialParams.kt
index 57622f08..eb8c1086 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialParams.kt
@@ -18,6 +18,7 @@ import com.withorb.api.core.BaseSerializer
 import com.withorb.api.core.Enum
 import com.withorb.api.core.ExcludeMissing
 import com.withorb.api.core.JsonField
+import com.withorb.api.core.JsonMissing
 import com.withorb.api.core.JsonValue
 import com.withorb.api.core.NoAutoDetect
 import com.withorb.api.core.getOrThrow
@@ -30,6 +31,24 @@ import java.time.OffsetDateTime
 import java.util.Objects
 import java.util.Optional
 
+/**
+ * This endpoint is used to update the trial end date for a subscription. The new trial end date
+ * must be within the time range of the current plan (i.e. the new trial end date must be on or
+ * after the subscription's start date on the current plan, and on or before the subscription end
+ * date).
+ *
+ * In order to retroactively remove a trial completely, the end date can be set to the transition
+ * date of the subscription to this plan (or, if this is the first plan for this subscription, the
+ * subscription's start date). In order to end a trial immediately, the keyword `immediate` can be
+ * provided as the trial end date.
+ *
+ * By default, Orb will shift only the trial end date (and price intervals that start or end on the
+ * previous trial end date), and leave all other future price intervals untouched. If the `shift`
+ * parameter is set to `true`, Orb will shift all subsequent price and adjustment intervals by the
+ * same amount as the trial end date shift (so, e.g., if a plan change is scheduled or an add-on
+ * price was added, that change will be pushed back by the same amount of time the trial is
+ * extended).
+ */
 class SubscriptionUpdateTrialParams
 constructor(
     private val subscriptionId: String,
@@ -52,12 +71,24 @@ constructor(
      */
     fun shift(): Optional<Boolean> = body.shift()
 
-    fun _additionalHeaders(): Headers = additionalHeaders
+    /**
+     * The new date that the trial should end, or the literal string `immediate` to end the trial
+     * immediately.
+     */
+    fun _trialEndDate(): JsonField<TrialEndDate> = body._trialEndDate()
 
-    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+    /**
+     * If true, shifts subsequent price and adjustment intervals (preserving their durations, but
+     * adjusting their absolute dates).
+     */
+    fun _shift(): JsonField<Boolean> = body._shift()
 
     fun _additionalBodyProperties(): Map<String, JsonValue> = body._additionalProperties()
 
+    fun _additionalHeaders(): Headers = additionalHeaders
+
+    fun _additionalQueryParams(): QueryParams = additionalQueryParams
+
     @JvmSynthetic internal fun getBody(): SubscriptionUpdateTrialBody = body
 
     @JvmSynthetic internal fun getHeaders(): Headers = additionalHeaders
@@ -75,8 +106,12 @@ constructor(
     class SubscriptionUpdateTrialBody
     @JsonCreator
     internal constructor(
-        @JsonProperty("trial_end_date") private val trialEndDate: TrialEndDate,
-        @JsonProperty("shift") private val shift: Boolean?,
+        @JsonProperty("trial_end_date")
+        @ExcludeMissing
+        private val trialEndDate: JsonField<TrialEndDate> = JsonMissing.of(),
+        @JsonProperty("shift")
+        @ExcludeMissing
+        private val shift: JsonField<Boolean> = JsonMissing.of(),
         @JsonAnySetter
         private val additionalProperties: Map<String, JsonValue> = immutableEmptyMap(),
     ) {
@@ -85,18 +120,42 @@ constructor(
          * The new date that the trial should end, or the literal string `immediate` to end the
          * trial immediately.
          */
-        @JsonProperty("trial_end_date") fun trialEndDate(): TrialEndDate = trialEndDate
+        fun trialEndDate(): TrialEndDate = trialEndDate.getRequired("trial_end_date")
+
+        /**
+         * If true, shifts subsequent price and adjustment intervals (preserving their durations,
+         * but adjusting their absolute dates).
+         */
+        fun shift(): Optional<Boolean> = Optional.ofNullable(shift.getNullable("shift"))
+
+        /**
+         * The new date that the trial should end, or the literal string `immediate` to end the
+         * trial immediately.
+         */
+        @JsonProperty("trial_end_date")
+        @ExcludeMissing
+        fun _trialEndDate(): JsonField<TrialEndDate> = trialEndDate
 
         /**
          * If true, shifts subsequent price and adjustment intervals (preserving their durations,
          * but adjusting their absolute dates).
          */
-        @JsonProperty("shift") fun shift(): Optional<Boolean> = Optional.ofNullable(shift)
+        @JsonProperty("shift") @ExcludeMissing fun _shift(): JsonField<Boolean> = shift
 
         @JsonAnyGetter
         @ExcludeMissing
         fun _additionalProperties(): Map<String, JsonValue> = additionalProperties
 
+        private var validated: Boolean = false
+
+        fun validate(): SubscriptionUpdateTrialBody = apply {
+            if (!validated) {
+                trialEndDate()
+                shift()
+                validated = true
+            }
+        }
+
         fun toBuilder() = Builder().from(this)
 
         companion object {
@@ -106,8 +165,8 @@ constructor(
 
         class Builder {
 
-            private var trialEndDate: TrialEndDate? = null
-            private var shift: Boolean? = null
+            private var trialEndDate: JsonField<TrialEndDate>? = null
+            private var shift: JsonField<Boolean> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -122,36 +181,33 @@ constructor(
              * The new date that the trial should end, or the literal string `immediate` to end the
              * trial immediately.
              */
-            fun trialEndDate(trialEndDate: TrialEndDate) = apply {
-                this.trialEndDate = trialEndDate
-            }
+            fun trialEndDate(trialEndDate: TrialEndDate) = trialEndDate(JsonField.of(trialEndDate))
 
-            fun trialEndDate(offsetDateTime: OffsetDateTime) = apply {
-                this.trialEndDate = TrialEndDate.ofOffsetDateTime(offsetDateTime)
+            /**
+             * The new date that the trial should end, or the literal string `immediate` to end the
+             * trial immediately.
+             */
+            fun trialEndDate(trialEndDate: JsonField<TrialEndDate>) = apply {
+                this.trialEndDate = trialEndDate
             }
 
-            fun trialEndDate(unionMember1: TrialEndDate.UnionMember1) = apply {
-                this.trialEndDate = TrialEndDate.ofUnionMember1(unionMember1)
-            }
+            fun trialEndDate(offsetDateTime: OffsetDateTime) =
+                trialEndDate(TrialEndDate.ofOffsetDateTime(offsetDateTime))
 
-            /**
-             * If true, shifts subsequent price and adjustment intervals (preserving their
-             * durations, but adjusting their absolute dates).
-             */
-            fun shift(shift: Boolean?) = apply { this.shift = shift }
+            fun trialEndDate(unionMember1: TrialEndDate.UnionMember1) =
+                trialEndDate(TrialEndDate.ofUnionMember1(unionMember1))
 
             /**
              * If true, shifts subsequent price and adjustment intervals (preserving their
              * durations, but adjusting their absolute dates).
              */
-            fun shift(shift: Boolean) = shift(shift as Boolean?)
+            fun shift(shift: Boolean) = shift(JsonField.of(shift))
 
             /**
              * If true, shifts subsequent price and adjustment intervals (preserving their
              * durations, but adjusting their absolute dates).
              */
-            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-            fun shift(shift: Optional<Boolean>) = shift(shift.orElse(null) as Boolean?)
+            fun shift(shift: JsonField<Boolean>) = apply { this.shift = shift }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -230,6 +286,14 @@ constructor(
          */
         fun trialEndDate(trialEndDate: TrialEndDate) = apply { body.trialEndDate(trialEndDate) }
 
+        /**
+         * The new date that the trial should end, or the literal string `immediate` to end the
+         * trial immediately.
+         */
+        fun trialEndDate(trialEndDate: JsonField<TrialEndDate>) = apply {
+            body.trialEndDate(trialEndDate)
+        }
+
         fun trialEndDate(offsetDateTime: OffsetDateTime) = apply {
             body.trialEndDate(offsetDateTime)
         }
@@ -242,20 +306,32 @@ constructor(
          * If true, shifts subsequent price and adjustment intervals (preserving their durations,
          * but adjusting their absolute dates).
          */
-        fun shift(shift: Boolean?) = apply { body.shift(shift) }
+        fun shift(shift: Boolean) = apply { body.shift(shift) }
 
         /**
          * If true, shifts subsequent price and adjustment intervals (preserving their durations,
          * but adjusting their absolute dates).
          */
-        fun shift(shift: Boolean) = shift(shift as Boolean?)
+        fun shift(shift: JsonField<Boolean>) = apply { body.shift(shift) }
 
-        /**
-         * If true, shifts subsequent price and adjustment intervals (preserving their durations,
-         * but adjusting their absolute dates).
-         */
-        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
-        fun shift(shift: Optional<Boolean>) = shift(shift.orElse(null) as Boolean?)
+        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
+            body.additionalProperties(additionalBodyProperties)
+        }
+
+        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
+            body.putAdditionalProperty(key, value)
+        }
+
+        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
+            apply {
+                body.putAllAdditionalProperties(additionalBodyProperties)
+            }
+
+        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
+
+        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
+            body.removeAllAdditionalProperties(keys)
+        }
 
         fun additionalHeaders(additionalHeaders: Headers) = apply {
             this.additionalHeaders.clear()
@@ -355,25 +431,6 @@ constructor(
             additionalQueryParams.removeAll(keys)
         }
 
-        fun additionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) = apply {
-            body.additionalProperties(additionalBodyProperties)
-        }
-
-        fun putAdditionalBodyProperty(key: String, value: JsonValue) = apply {
-            body.putAdditionalProperty(key, value)
-        }
-
-        fun putAllAdditionalBodyProperties(additionalBodyProperties: Map<String, JsonValue>) =
-            apply {
-                body.putAllAdditionalProperties(additionalBodyProperties)
-            }
-
-        fun removeAdditionalBodyProperty(key: String) = apply { body.removeAdditionalProperty(key) }
-
-        fun removeAllAdditionalBodyProperties(keys: Set<String>) = apply {
-            body.removeAllAdditionalProperties(keys)
-        }
-
         fun build(): SubscriptionUpdateTrialParams =
             SubscriptionUpdateTrialParams(
                 checkNotNull(subscriptionId) { "`subscriptionId` is required but was not set" },
@@ -396,6 +453,8 @@ constructor(
         private val _json: JsonValue? = null,
     ) {
 
+        private var validated: Boolean = false
+
         fun offsetDateTime(): Optional<OffsetDateTime> = Optional.ofNullable(offsetDateTime)
 
         fun unionMember1(): Optional<UnionMember1> = Optional.ofNullable(unionMember1)
@@ -418,6 +477,15 @@ constructor(
             }
         }
 
+        fun validate(): TrialEndDate = apply {
+            if (!validated) {
+                if (offsetDateTime == null && unionMember1 == null) {
+                    throw OrbInvalidDataException("Unknown TrialEndDate: $_json")
+                }
+                validated = true
+            }
+        }
+
         override fun equals(other: Any?): Boolean {
             if (this === other) {
                 return true
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialResponse.kt
index f842f301..fdd99415 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUpdateTrialResponse.kt
@@ -242,37 +242,44 @@ private constructor(
 
     fun trialInfo(): TrialInfo = trialInfo.getRequired("trial_info")
 
-    @JsonProperty("id") @ExcludeMissing fun _id() = id
+    @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
     /** The current plan phase that is active, only if the subscription's plan has phases. */
     @JsonProperty("active_plan_phase_order")
     @ExcludeMissing
-    fun _activePlanPhaseOrder() = activePlanPhaseOrder
+    fun _activePlanPhaseOrder(): JsonField<Long> = activePlanPhaseOrder
 
     /** The adjustment intervals for this subscription. */
     @JsonProperty("adjustment_intervals")
     @ExcludeMissing
-    fun _adjustmentIntervals() = adjustmentIntervals
+    fun _adjustmentIntervals(): JsonField<List<AdjustmentInterval>> = adjustmentIntervals
 
     /**
      * Determines whether issued invoices for this subscription will automatically be charged with
      * the saved payment method on the due date. This property defaults to the plan's behavior. If
      * null, defaults to the customer's setting.
      */
-    @JsonProperty("auto_collection") @ExcludeMissing fun _autoCollection() = autoCollection
+    @JsonProperty("auto_collection")
+    @ExcludeMissing
+    fun _autoCollection(): JsonField<Boolean> = autoCollection
 
     @JsonProperty("billing_cycle_anchor_configuration")
     @ExcludeMissing
-    fun _billingCycleAnchorConfiguration() = billingCycleAnchorConfiguration
+    fun _billingCycleAnchorConfiguration(): JsonField<BillingCycleAnchorConfiguration> =
+        billingCycleAnchorConfiguration
 
     /**
      * The day of the month on which the billing cycle is anchored. If the maximum number of days in
      * a month is greater than this value, the last day of the month is the billing cycle day (e.g.
      * billing_cycle_day=31 for April means the billing period begins on the 30th.
      */
-    @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+    @JsonProperty("billing_cycle_day")
+    @ExcludeMissing
+    fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
-    @JsonProperty("created_at") @ExcludeMissing fun _createdAt() = createdAt
+    @JsonProperty("created_at")
+    @ExcludeMissing
+    fun _createdAt(): JsonField<OffsetDateTime> = createdAt
 
     /**
      * The end of the current billing period. This is an exclusive timestamp, such that the instant
@@ -281,7 +288,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_end_date")
     @ExcludeMissing
-    fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+    fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
     /**
      * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -290,7 +297,7 @@ private constructor(
      */
     @JsonProperty("current_billing_period_start_date")
     @ExcludeMissing
-    fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+    fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> = currentBillingPeriodStartDate
 
     /**
      * A customer is a buyer of your products, and the other party to the billing relationship.
@@ -310,7 +317,7 @@ private constructor(
      * timezone. See [Timezone localization](../guides/product-catalog/timezones.md) for information
      * on what this timezone parameter influences within Orb.
      */
-    @JsonProperty("customer") @ExcludeMissing fun _customer() = customer
+    @JsonProperty("customer") @ExcludeMissing fun _customer(): JsonField<Customer> = customer
 
     /**
      * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -318,60 +325,73 @@ private constructor(
      */
     @JsonProperty("default_invoice_memo")
     @ExcludeMissing
-    fun _defaultInvoiceMemo() = defaultInvoiceMemo
+    fun _defaultInvoiceMemo(): JsonField<String> = defaultInvoiceMemo
 
     /** The discount intervals for this subscription. */
-    @JsonProperty("discount_intervals") @ExcludeMissing fun _discountIntervals() = discountIntervals
+    @JsonProperty("discount_intervals")
+    @ExcludeMissing
+    fun _discountIntervals(): JsonField<List<DiscountInterval>> = discountIntervals
 
     /** The date Orb stops billing for this subscription. */
-    @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+    @JsonProperty("end_date") @ExcludeMissing fun _endDate(): JsonField<OffsetDateTime> = endDate
 
     @JsonProperty("fixed_fee_quantity_schedule")
     @ExcludeMissing
-    fun _fixedFeeQuantitySchedule() = fixedFeeQuantitySchedule
+    fun _fixedFeeQuantitySchedule(): JsonField<List<FixedFeeQuantitySchedule>> =
+        fixedFeeQuantitySchedule
 
     @JsonProperty("invoicing_threshold")
     @ExcludeMissing
-    fun _invoicingThreshold() = invoicingThreshold
+    fun _invoicingThreshold(): JsonField<String> = invoicingThreshold
 
     /** The maximum intervals for this subscription. */
-    @JsonProperty("maximum_intervals") @ExcludeMissing fun _maximumIntervals() = maximumIntervals
+    @JsonProperty("maximum_intervals")
+    @ExcludeMissing
+    fun _maximumIntervals(): JsonField<List<MaximumInterval>> = maximumIntervals
 
     /**
      * User specified key-value pairs for the resource. If not present, this defaults to an empty
      * dictionary. Individual keys can be removed by setting the value to `null`, and the entire
      * metadata mapping can be cleared by setting `metadata` to `null`.
      */
-    @JsonProperty("metadata") @ExcludeMissing fun _metadata() = metadata
+    @JsonProperty("metadata") @ExcludeMissing fun _metadata(): JsonField<Metadata> = metadata
 
     /** The minimum intervals for this subscription. */
-    @JsonProperty("minimum_intervals") @ExcludeMissing fun _minimumIntervals() = minimumIntervals
+    @JsonProperty("minimum_intervals")
+    @ExcludeMissing
+    fun _minimumIntervals(): JsonField<List<MinimumInterval>> = minimumIntervals
 
     /**
      * Determines the difference between the invoice issue date for subscription invoices as the
      * date that they are due. A value of `0` here represents that the invoice is due on issue,
      * whereas a value of `30` represents that the customer has a month to pay the invoice.
      */
-    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms() = netTerms
+    @JsonProperty("net_terms") @ExcludeMissing fun _netTerms(): JsonField<Long> = netTerms
 
     /**
      * The [Plan](../guides/core-concepts.mdx#plan-and-price) resource represents a plan that can be
      * subscribed to by a customer. Plans define the billing behavior of the subscription. You can
      * see more about how to configure prices in the [Price resource](/reference/price).
      */
-    @JsonProperty("plan") @ExcludeMissing fun _plan() = plan
+    @JsonProperty("plan") @ExcludeMissing fun _plan(): JsonField<Plan> = plan
 
     /** The price intervals for this subscription. */
-    @JsonProperty("price_intervals") @ExcludeMissing fun _priceIntervals() = priceIntervals
+    @JsonProperty("price_intervals")
+    @ExcludeMissing
+    fun _priceIntervals(): JsonField<List<PriceInterval>> = priceIntervals
 
-    @JsonProperty("redeemed_coupon") @ExcludeMissing fun _redeemedCoupon() = redeemedCoupon
+    @JsonProperty("redeemed_coupon")
+    @ExcludeMissing
+    fun _redeemedCoupon(): JsonField<RedeemedCoupon> = redeemedCoupon
 
     /** The date Orb starts billing for this subscription. */
-    @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+    @JsonProperty("start_date")
+    @ExcludeMissing
+    fun _startDate(): JsonField<OffsetDateTime> = startDate
 
-    @JsonProperty("status") @ExcludeMissing fun _status() = status
+    @JsonProperty("status") @ExcludeMissing fun _status(): JsonField<Status> = status
 
-    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo() = trialInfo
+    @JsonProperty("trial_info") @ExcludeMissing fun _trialInfo(): JsonField<TrialInfo> = trialInfo
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -419,33 +439,33 @@ private constructor(
 
     class Builder {
 
-        private var id: JsonField<String> = JsonMissing.of()
-        private var activePlanPhaseOrder: JsonField<Long> = JsonMissing.of()
-        private var adjustmentIntervals: JsonField<List<AdjustmentInterval>> = JsonMissing.of()
-        private var autoCollection: JsonField<Boolean> = JsonMissing.of()
-        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration> =
-            JsonMissing.of()
-        private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-        private var createdAt: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var customer: JsonField<Customer> = JsonMissing.of()
-        private var defaultInvoiceMemo: JsonField<String> = JsonMissing.of()
-        private var discountIntervals: JsonField<List<DiscountInterval>> = JsonMissing.of()
-        private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>> =
-            JsonMissing.of()
-        private var invoicingThreshold: JsonField<String> = JsonMissing.of()
-        private var maximumIntervals: JsonField<List<MaximumInterval>> = JsonMissing.of()
-        private var metadata: JsonField<Metadata> = JsonMissing.of()
-        private var minimumIntervals: JsonField<List<MinimumInterval>> = JsonMissing.of()
-        private var netTerms: JsonField<Long> = JsonMissing.of()
-        private var plan: JsonField<Plan> = JsonMissing.of()
-        private var priceIntervals: JsonField<List<PriceInterval>> = JsonMissing.of()
-        private var redeemedCoupon: JsonField<RedeemedCoupon> = JsonMissing.of()
-        private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-        private var status: JsonField<Status> = JsonMissing.of()
-        private var trialInfo: JsonField<TrialInfo> = JsonMissing.of()
+        private var id: JsonField<String>? = null
+        private var activePlanPhaseOrder: JsonField<Long>? = null
+        private var adjustmentIntervals: JsonField<MutableList<AdjustmentInterval>>? = null
+        private var autoCollection: JsonField<Boolean>? = null
+        private var billingCycleAnchorConfiguration: JsonField<BillingCycleAnchorConfiguration>? =
+            null
+        private var billingCycleDay: JsonField<Long>? = null
+        private var createdAt: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+        private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+        private var customer: JsonField<Customer>? = null
+        private var defaultInvoiceMemo: JsonField<String>? = null
+        private var discountIntervals: JsonField<MutableList<DiscountInterval>>? = null
+        private var endDate: JsonField<OffsetDateTime>? = null
+        private var fixedFeeQuantitySchedule: JsonField<MutableList<FixedFeeQuantitySchedule>>? =
+            null
+        private var invoicingThreshold: JsonField<String>? = null
+        private var maximumIntervals: JsonField<MutableList<MaximumInterval>>? = null
+        private var metadata: JsonField<Metadata>? = null
+        private var minimumIntervals: JsonField<MutableList<MinimumInterval>>? = null
+        private var netTerms: JsonField<Long>? = null
+        private var plan: JsonField<Plan>? = null
+        private var priceIntervals: JsonField<MutableList<PriceInterval>>? = null
+        private var redeemedCoupon: JsonField<RedeemedCoupon>? = null
+        private var startDate: JsonField<OffsetDateTime>? = null
+        private var status: JsonField<Status>? = null
+        private var trialInfo: JsonField<TrialInfo>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -453,7 +473,8 @@ private constructor(
             apply {
                 id = subscriptionUpdateTrialResponse.id
                 activePlanPhaseOrder = subscriptionUpdateTrialResponse.activePlanPhaseOrder
-                adjustmentIntervals = subscriptionUpdateTrialResponse.adjustmentIntervals
+                adjustmentIntervals =
+                    subscriptionUpdateTrialResponse.adjustmentIntervals.map { it.toMutableList() }
                 autoCollection = subscriptionUpdateTrialResponse.autoCollection
                 billingCycleAnchorConfiguration =
                     subscriptionUpdateTrialResponse.billingCycleAnchorConfiguration
@@ -465,16 +486,23 @@ private constructor(
                     subscriptionUpdateTrialResponse.currentBillingPeriodStartDate
                 customer = subscriptionUpdateTrialResponse.customer
                 defaultInvoiceMemo = subscriptionUpdateTrialResponse.defaultInvoiceMemo
-                discountIntervals = subscriptionUpdateTrialResponse.discountIntervals
+                discountIntervals =
+                    subscriptionUpdateTrialResponse.discountIntervals.map { it.toMutableList() }
                 endDate = subscriptionUpdateTrialResponse.endDate
-                fixedFeeQuantitySchedule = subscriptionUpdateTrialResponse.fixedFeeQuantitySchedule
+                fixedFeeQuantitySchedule =
+                    subscriptionUpdateTrialResponse.fixedFeeQuantitySchedule.map {
+                        it.toMutableList()
+                    }
                 invoicingThreshold = subscriptionUpdateTrialResponse.invoicingThreshold
-                maximumIntervals = subscriptionUpdateTrialResponse.maximumIntervals
+                maximumIntervals =
+                    subscriptionUpdateTrialResponse.maximumIntervals.map { it.toMutableList() }
                 metadata = subscriptionUpdateTrialResponse.metadata
-                minimumIntervals = subscriptionUpdateTrialResponse.minimumIntervals
+                minimumIntervals =
+                    subscriptionUpdateTrialResponse.minimumIntervals.map { it.toMutableList() }
                 netTerms = subscriptionUpdateTrialResponse.netTerms
                 plan = subscriptionUpdateTrialResponse.plan
-                priceIntervals = subscriptionUpdateTrialResponse.priceIntervals
+                priceIntervals =
+                    subscriptionUpdateTrialResponse.priceIntervals.map { it.toMutableList() }
                 redeemedCoupon = subscriptionUpdateTrialResponse.redeemedCoupon
                 startDate = subscriptionUpdateTrialResponse.startDate
                 status = subscriptionUpdateTrialResponse.status
@@ -487,9 +515,18 @@ private constructor(
 
         fun id(id: JsonField<String>) = apply { this.id = id }
 
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Long?) =
+            activePlanPhaseOrder(JsonField.ofNullable(activePlanPhaseOrder))
+
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: Long) =
-            activePlanPhaseOrder(JsonField.of(activePlanPhaseOrder))
+            activePlanPhaseOrder(activePlanPhaseOrder as Long?)
+
+        /** The current plan phase that is active, only if the subscription's plan has phases. */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun activePlanPhaseOrder(activePlanPhaseOrder: Optional<Long>) =
+            activePlanPhaseOrder(activePlanPhaseOrder.orElse(null) as Long?)
 
         /** The current plan phase that is active, only if the subscription's plan has phases. */
         fun activePlanPhaseOrder(activePlanPhaseOrder: JsonField<Long>) = apply {
@@ -502,15 +539,46 @@ private constructor(
 
         /** The adjustment intervals for this subscription. */
         fun adjustmentIntervals(adjustmentIntervals: JsonField<List<AdjustmentInterval>>) = apply {
-            this.adjustmentIntervals = adjustmentIntervals
+            this.adjustmentIntervals = adjustmentIntervals.map { it.toMutableList() }
         }
 
+        /** The adjustment intervals for this subscription. */
+        fun addAdjustmentInterval(adjustmentInterval: AdjustmentInterval) = apply {
+            adjustmentIntervals =
+                (adjustmentIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(adjustmentInterval)
+                }
+        }
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean?) =
+            autoCollection(JsonField.ofNullable(autoCollection))
+
+        /**
+         * Determines whether issued invoices for this subscription will automatically be charged
+         * with the saved payment method on the due date. This property defaults to the plan's
+         * behavior. If null, defaults to the customer's setting.
+         */
+        fun autoCollection(autoCollection: Boolean) = autoCollection(autoCollection as Boolean?)
+
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
          * with the saved payment method on the due date. This property defaults to the plan's
          * behavior. If null, defaults to the customer's setting.
          */
-        fun autoCollection(autoCollection: Boolean) = autoCollection(JsonField.of(autoCollection))
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun autoCollection(autoCollection: Optional<Boolean>) =
+            autoCollection(autoCollection.orElse(null) as Boolean?)
 
         /**
          * Determines whether issued invoices for this subscription will automatically be charged
@@ -556,8 +624,16 @@ private constructor(
          * instant returned is not part of the billing period. Set to null for subscriptions that
          * are not currently active.
          */
-        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-            currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+            currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+        /**
+         * The end of the current billing period. This is an exclusive timestamp, such that the
+         * instant returned is not part of the billing period. Set to null for subscriptions that
+         * are not currently active.
+         */
+        fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -574,8 +650,16 @@ private constructor(
          * returned is exactly the beginning of the billing period. Set to null if the subscription
          * is not currently active.
          */
-        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-            currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+            currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+        /**
+         * The start date of the current billing period. This is an inclusive timestamp; the instant
+         * returned is exactly the beginning of the billing period. Set to null if the subscription
+         * is not currently active.
+         */
+        fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: Optional<OffsetDateTime>) =
+            currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -630,8 +714,15 @@ private constructor(
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
          * provided, it is determined by the plan configuration.
          */
-        fun defaultInvoiceMemo(defaultInvoiceMemo: String) =
-            defaultInvoiceMemo(JsonField.of(defaultInvoiceMemo))
+        fun defaultInvoiceMemo(defaultInvoiceMemo: String?) =
+            defaultInvoiceMemo(JsonField.ofNullable(defaultInvoiceMemo))
+
+        /**
+         * Determines the default memo on this subscriptions' invoices. Note that if this is not
+         * provided, it is determined by the plan configuration.
+         */
+        fun defaultInvoiceMemo(defaultInvoiceMemo: Optional<String>) =
+            defaultInvoiceMemo(defaultInvoiceMemo.orElse(null))
 
         /**
          * Determines the default memo on this subscriptions' invoices. Note that if this is not
@@ -647,11 +738,28 @@ private constructor(
 
         /** The discount intervals for this subscription. */
         fun discountIntervals(discountIntervals: JsonField<List<DiscountInterval>>) = apply {
-            this.discountIntervals = discountIntervals
+            this.discountIntervals = discountIntervals.map { it.toMutableList() }
+        }
+
+        /** The discount intervals for this subscription. */
+        fun addDiscountInterval(discountInterval: DiscountInterval) = apply {
+            discountIntervals =
+                (discountIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(discountInterval)
+                }
         }
 
         /** The date Orb stops billing for this subscription. */
-        fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+        fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+        /** The date Orb stops billing for this subscription. */
+        fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
         /** The date Orb stops billing for this subscription. */
         fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -661,10 +769,29 @@ private constructor(
 
         fun fixedFeeQuantitySchedule(
             fixedFeeQuantitySchedule: JsonField<List<FixedFeeQuantitySchedule>>
-        ) = apply { this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule }
+        ) = apply {
+            this.fixedFeeQuantitySchedule = fixedFeeQuantitySchedule.map { it.toMutableList() }
+        }
+
+        fun addFixedFeeQuantitySchedule(fixedFeeQuantitySchedule: FixedFeeQuantitySchedule) =
+            apply {
+                this.fixedFeeQuantitySchedule =
+                    (this.fixedFeeQuantitySchedule ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantitySchedule)
+                    }
+            }
 
-        fun invoicingThreshold(invoicingThreshold: String) =
-            invoicingThreshold(JsonField.of(invoicingThreshold))
+        fun invoicingThreshold(invoicingThreshold: String?) =
+            invoicingThreshold(JsonField.ofNullable(invoicingThreshold))
+
+        fun invoicingThreshold(invoicingThreshold: Optional<String>) =
+            invoicingThreshold(invoicingThreshold.orElse(null))
 
         fun invoicingThreshold(invoicingThreshold: JsonField<String>) = apply {
             this.invoicingThreshold = invoicingThreshold
@@ -676,7 +803,21 @@ private constructor(
 
         /** The maximum intervals for this subscription. */
         fun maximumIntervals(maximumIntervals: JsonField<List<MaximumInterval>>) = apply {
-            this.maximumIntervals = maximumIntervals
+            this.maximumIntervals = maximumIntervals.map { it.toMutableList() }
+        }
+
+        /** The maximum intervals for this subscription. */
+        fun addMaximumInterval(maximumInterval: MaximumInterval) = apply {
+            maximumIntervals =
+                (maximumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(maximumInterval)
+                }
         }
 
         /**
@@ -699,7 +840,21 @@ private constructor(
 
         /** The minimum intervals for this subscription. */
         fun minimumIntervals(minimumIntervals: JsonField<List<MinimumInterval>>) = apply {
-            this.minimumIntervals = minimumIntervals
+            this.minimumIntervals = minimumIntervals.map { it.toMutableList() }
+        }
+
+        /** The minimum intervals for this subscription. */
+        fun addMinimumInterval(minimumInterval: MinimumInterval) = apply {
+            minimumIntervals =
+                (minimumIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(minimumInterval)
+                }
         }
 
         /**
@@ -738,11 +893,28 @@ private constructor(
 
         /** The price intervals for this subscription. */
         fun priceIntervals(priceIntervals: JsonField<List<PriceInterval>>) = apply {
-            this.priceIntervals = priceIntervals
+            this.priceIntervals = priceIntervals.map { it.toMutableList() }
+        }
+
+        /** The price intervals for this subscription. */
+        fun addPriceInterval(priceInterval: PriceInterval) = apply {
+            priceIntervals =
+                (priceIntervals ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(priceInterval)
+                }
         }
 
-        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon) =
-            redeemedCoupon(JsonField.of(redeemedCoupon))
+        fun redeemedCoupon(redeemedCoupon: RedeemedCoupon?) =
+            redeemedCoupon(JsonField.ofNullable(redeemedCoupon))
+
+        fun redeemedCoupon(redeemedCoupon: Optional<RedeemedCoupon>) =
+            redeemedCoupon(redeemedCoupon.orElse(null))
 
         fun redeemedCoupon(redeemedCoupon: JsonField<RedeemedCoupon>) = apply {
             this.redeemedCoupon = redeemedCoupon
@@ -783,31 +955,55 @@ private constructor(
 
         fun build(): SubscriptionUpdateTrialResponse =
             SubscriptionUpdateTrialResponse(
-                id,
-                activePlanPhaseOrder,
-                adjustmentIntervals.map { it.toImmutable() },
-                autoCollection,
-                billingCycleAnchorConfiguration,
-                billingCycleDay,
-                createdAt,
-                currentBillingPeriodEndDate,
-                currentBillingPeriodStartDate,
-                customer,
-                defaultInvoiceMemo,
-                discountIntervals.map { it.toImmutable() },
-                endDate,
-                fixedFeeQuantitySchedule.map { it.toImmutable() },
-                invoicingThreshold,
-                maximumIntervals.map { it.toImmutable() },
-                metadata,
-                minimumIntervals.map { it.toImmutable() },
-                netTerms,
-                plan,
-                priceIntervals.map { it.toImmutable() },
-                redeemedCoupon,
-                startDate,
-                status,
-                trialInfo,
+                checkNotNull(id) { "`id` is required but was not set" },
+                checkNotNull(activePlanPhaseOrder) {
+                    "`activePlanPhaseOrder` is required but was not set"
+                },
+                checkNotNull(adjustmentIntervals) {
+                        "`adjustmentIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(autoCollection) { "`autoCollection` is required but was not set" },
+                checkNotNull(billingCycleAnchorConfiguration) {
+                    "`billingCycleAnchorConfiguration` is required but was not set"
+                },
+                checkNotNull(billingCycleDay) { "`billingCycleDay` is required but was not set" },
+                checkNotNull(createdAt) { "`createdAt` is required but was not set" },
+                checkNotNull(currentBillingPeriodEndDate) {
+                    "`currentBillingPeriodEndDate` is required but was not set"
+                },
+                checkNotNull(currentBillingPeriodStartDate) {
+                    "`currentBillingPeriodStartDate` is required but was not set"
+                },
+                checkNotNull(customer) { "`customer` is required but was not set" },
+                checkNotNull(defaultInvoiceMemo) {
+                    "`defaultInvoiceMemo` is required but was not set"
+                },
+                checkNotNull(discountIntervals) {
+                        "`discountIntervals` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(endDate) { "`endDate` is required but was not set" },
+                checkNotNull(fixedFeeQuantitySchedule) {
+                        "`fixedFeeQuantitySchedule` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(invoicingThreshold) {
+                    "`invoicingThreshold` is required but was not set"
+                },
+                checkNotNull(maximumIntervals) { "`maximumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(metadata) { "`metadata` is required but was not set" },
+                checkNotNull(minimumIntervals) { "`minimumIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(netTerms) { "`netTerms` is required but was not set" },
+                checkNotNull(plan) { "`plan` is required but was not set" },
+                checkNotNull(priceIntervals) { "`priceIntervals` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(redeemedCoupon) { "`redeemedCoupon` is required but was not set" },
+                checkNotNull(startDate) { "`startDate` is required but was not set" },
+                checkNotNull(status) { "`status` is required but was not set" },
+                checkNotNull(trialInfo) { "`trialInfo` is required but was not set" },
                 additionalProperties.toImmutable(),
             )
     }
@@ -848,20 +1044,26 @@ private constructor(
         /** The start date of the adjustment interval. */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-        @JsonProperty("adjustment") @ExcludeMissing fun _adjustment() = adjustment
+        @JsonProperty("adjustment")
+        @ExcludeMissing
+        fun _adjustment(): JsonField<Adjustment> = adjustment
 
         /** The price interval IDs that this adjustment applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the adjustment interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /** The start date of the adjustment interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -889,18 +1091,19 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var adjustment: JsonField<Adjustment> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var adjustment: JsonField<Adjustment>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(adjustmentInterval: AdjustmentInterval) = apply {
                 id = adjustmentInterval.id
                 adjustment = adjustmentInterval.adjustment
-                appliesToPriceIntervalIds = adjustmentInterval.appliesToPriceIntervalIds
+                appliesToPriceIntervalIds =
+                    adjustmentInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = adjustmentInterval.endDate
                 startDate = adjustmentInterval.startDate
                 additionalProperties = adjustmentInterval.additionalProperties.toMutableMap()
@@ -916,6 +1119,21 @@ private constructor(
                 this.adjustment = adjustment
             }
 
+            fun adjustment(amountDiscountAdjustment: Adjustment.AmountDiscountAdjustment) =
+                adjustment(Adjustment.ofAmountDiscountAdjustment(amountDiscountAdjustment))
+
+            fun adjustment(percentageDiscountAdjustment: Adjustment.PercentageDiscountAdjustment) =
+                adjustment(Adjustment.ofPercentageDiscountAdjustment(percentageDiscountAdjustment))
+
+            fun adjustment(usageDiscountAdjustment: Adjustment.UsageDiscountAdjustment) =
+                adjustment(Adjustment.ofUsageDiscountAdjustment(usageDiscountAdjustment))
+
+            fun adjustment(minimumAdjustment: Adjustment.MinimumAdjustment) =
+                adjustment(Adjustment.ofMinimumAdjustment(minimumAdjustment))
+
+            fun adjustment(maximumAdjustment: Adjustment.MaximumAdjustment) =
+                adjustment(Adjustment.ofMaximumAdjustment(maximumAdjustment))
+
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: List<String>) =
                 appliesToPriceIntervalIds(JsonField.of(appliesToPriceIntervalIds))
@@ -923,11 +1141,29 @@ private constructor(
             /** The price interval IDs that this adjustment applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval IDs that this adjustment applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
             /** The end date of the adjustment interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /** The end date of the adjustment interval. */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the adjustment interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -961,11 +1197,14 @@ private constructor(
 
             fun build(): AdjustmentInterval =
                 AdjustmentInterval(
-                    id,
-                    adjustment,
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(adjustment) { "`adjustment` is required but was not set" },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -1268,11 +1507,11 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /**
                  * The amount by which to discount the prices this adjustment applies to in a given
@@ -1280,12 +1519,12 @@ private constructor(
                  */
                 @JsonProperty("amount_discount")
                 @ExcludeMissing
-                fun _amountDiscount() = amountDiscount
+                fun _amountDiscount(): JsonField<String> = amountDiscount
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1293,15 +1532,15 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1331,13 +1570,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var amountDiscount: JsonField<String> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var amountDiscount: JsonField<String>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1345,7 +1584,8 @@ private constructor(
                         id = amountDiscountAdjustment.id
                         adjustmentType = amountDiscountAdjustment.adjustmentType
                         amountDiscount = amountDiscountAdjustment.amountDiscount
-                        appliesToPriceIds = amountDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            amountDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = amountDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = amountDiscountAdjustment.planPhaseOrder
                         reason = amountDiscountAdjustment.reason
@@ -1385,7 +1625,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1403,9 +1657,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1413,7 +1676,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1442,13 +1708,24 @@ private constructor(
 
                     fun build(): AmountDiscountAdjustment =
                         AmountDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            amountDiscount,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(amountDiscount) {
+                                "`amountDiscount` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1580,16 +1857,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1597,7 +1874,7 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The percentage (as a value between 0 and 1) by which to discount the price
@@ -1605,15 +1882,15 @@ private constructor(
                  */
                 @JsonProperty("percentage_discount")
                 @ExcludeMissing
-                fun _percentageDiscount() = percentageDiscount
+                fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1643,13 +1920,13 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var percentageDiscount: JsonField<Double>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1657,7 +1934,10 @@ private constructor(
                         apply {
                             id = percentageDiscountAdjustment.id
                             adjustmentType = percentageDiscountAdjustment.adjustmentType
-                            appliesToPriceIds = percentageDiscountAdjustment.appliesToPriceIds
+                            appliesToPriceIds =
+                                percentageDiscountAdjustment.appliesToPriceIds.map {
+                                    it.toMutableList()
+                                }
                             isInvoiceLevel = percentageDiscountAdjustment.isInvoiceLevel
                             percentageDiscount = percentageDiscountAdjustment.percentageDiscount
                             planPhaseOrder = percentageDiscountAdjustment.planPhaseOrder
@@ -1683,7 +1963,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -1716,9 +2010,18 @@ private constructor(
                         this.percentageDiscount = percentageDiscount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -1726,7 +2029,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -1755,13 +2061,24 @@ private constructor(
 
                     fun build(): PercentageDiscountAdjustment =
                         PercentageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            percentageDiscount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(percentageDiscount) {
+                                "`percentageDiscount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1892,16 +2209,16 @@ private constructor(
                  */
                 fun usageDiscount(): Double = usageDiscount.getRequired("usage_discount")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -1909,21 +2226,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 /**
                  * The number of usage units by which to discount the price this adjustment applies
                  * to in a given billing period.
                  */
-                @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+                @JsonProperty("usage_discount")
+                @ExcludeMissing
+                fun _usageDiscount(): JsonField<Double> = usageDiscount
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1953,20 +2272,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
-                    private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
+                    private var usageDiscount: JsonField<Double>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(usageDiscountAdjustment: UsageDiscountAdjustment) = apply {
                         id = usageDiscountAdjustment.id
                         adjustmentType = usageDiscountAdjustment.adjustmentType
-                        appliesToPriceIds = usageDiscountAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            usageDiscountAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = usageDiscountAdjustment.isInvoiceLevel
                         planPhaseOrder = usageDiscountAdjustment.planPhaseOrder
                         reason = usageDiscountAdjustment.reason
@@ -1992,7 +2312,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2010,9 +2344,18 @@ private constructor(
                         this.isInvoiceLevel = isInvoiceLevel
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2020,7 +2363,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2064,13 +2410,24 @@ private constructor(
 
                     fun build(): UsageDiscountAdjustment =
                         UsageDiscountAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            planPhaseOrder,
-                            reason,
-                            usageDiscount,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
+                            checkNotNull(usageDiscount) {
+                                "`usageDiscount` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2207,16 +2564,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2224,24 +2581,26 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /** The item ID that revenue from this minimum will be attributed to. */
-                @JsonProperty("item_id") @ExcludeMissing fun _itemId() = itemId
+                @JsonProperty("item_id") @ExcludeMissing fun _itemId(): JsonField<String> = itemId
 
                 /**
                  * The minimum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+                @JsonProperty("minimum_amount")
+                @ExcludeMissing
+                fun _minimumAmount(): JsonField<String> = minimumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2272,21 +2631,22 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var itemId: JsonField<String> = JsonMissing.of()
-                    private var minimumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var itemId: JsonField<String>? = null
+                    private var minimumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(minimumAdjustment: MinimumAdjustment) = apply {
                         id = minimumAdjustment.id
                         adjustmentType = minimumAdjustment.adjustmentType
-                        appliesToPriceIds = minimumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            minimumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = minimumAdjustment.isInvoiceLevel
                         itemId = minimumAdjustment.itemId
                         minimumAmount = minimumAdjustment.minimumAmount
@@ -2312,7 +2672,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2351,9 +2725,18 @@ private constructor(
                         this.minimumAmount = minimumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2361,7 +2744,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2390,14 +2776,25 @@ private constructor(
 
                     fun build(): MinimumAdjustment =
                         MinimumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            itemId,
-                            minimumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(itemId) { "`itemId` is required but was not set" },
+                            checkNotNull(minimumAmount) {
+                                "`minimumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2528,16 +2925,16 @@ private constructor(
                 /** The reason for the adjustment. */
                 fun reason(): Optional<String> = Optional.ofNullable(reason.getNullable("reason"))
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
                 @JsonProperty("adjustment_type")
                 @ExcludeMissing
-                fun _adjustmentType() = adjustmentType
+                fun _adjustmentType(): JsonField<AdjustmentType> = adjustmentType
 
                 /** The price IDs that this adjustment applies to. */
                 @JsonProperty("applies_to_price_ids")
                 @ExcludeMissing
-                fun _appliesToPriceIds() = appliesToPriceIds
+                fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
                 /**
                  * True for adjustments that apply to an entire invocice, false for adjustments that
@@ -2545,21 +2942,23 @@ private constructor(
                  */
                 @JsonProperty("is_invoice_level")
                 @ExcludeMissing
-                fun _isInvoiceLevel() = isInvoiceLevel
+                fun _isInvoiceLevel(): JsonField<Boolean> = isInvoiceLevel
 
                 /**
                  * The maximum amount to charge in a given billing period for the prices this
                  * adjustment applies to.
                  */
-                @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+                @JsonProperty("maximum_amount")
+                @ExcludeMissing
+                fun _maximumAmount(): JsonField<String> = maximumAmount
 
                 /** The plan phase in which this adjustment is active. */
                 @JsonProperty("plan_phase_order")
                 @ExcludeMissing
-                fun _planPhaseOrder() = planPhaseOrder
+                fun _planPhaseOrder(): JsonField<Long> = planPhaseOrder
 
                 /** The reason for the adjustment. */
-                @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+                @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -2589,20 +2988,21 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var adjustmentType: JsonField<AdjustmentType> = JsonMissing.of()
-                    private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                    private var isInvoiceLevel: JsonField<Boolean> = JsonMissing.of()
-                    private var maximumAmount: JsonField<String> = JsonMissing.of()
-                    private var planPhaseOrder: JsonField<Long> = JsonMissing.of()
-                    private var reason: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var adjustmentType: JsonField<AdjustmentType>? = null
+                    private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                    private var isInvoiceLevel: JsonField<Boolean>? = null
+                    private var maximumAmount: JsonField<String>? = null
+                    private var planPhaseOrder: JsonField<Long>? = null
+                    private var reason: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
                     internal fun from(maximumAdjustment: MaximumAdjustment) = apply {
                         id = maximumAdjustment.id
                         adjustmentType = maximumAdjustment.adjustmentType
-                        appliesToPriceIds = maximumAdjustment.appliesToPriceIds
+                        appliesToPriceIds =
+                            maximumAdjustment.appliesToPriceIds.map { it.toMutableList() }
                         isInvoiceLevel = maximumAdjustment.isInvoiceLevel
                         maximumAmount = maximumAdjustment.maximumAmount
                         planPhaseOrder = maximumAdjustment.planPhaseOrder
@@ -2627,7 +3027,21 @@ private constructor(
 
                     /** The price IDs that this adjustment applies to. */
                     fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                        this.appliesToPriceIds = appliesToPriceIds
+                        this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                    }
+
+                    /** The price IDs that this adjustment applies to. */
+                    fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                        appliesToPriceIds =
+                            (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                                asKnown()
+                                    .orElseThrow {
+                                        IllegalStateException(
+                                            "Field was set to non-list type: ${javaClass.simpleName}"
+                                        )
+                                    }
+                                    .add(appliesToPriceId)
+                            }
                     }
 
                     /**
@@ -2660,9 +3074,18 @@ private constructor(
                         this.maximumAmount = maximumAmount
                     }
 
+                    /** The plan phase in which this adjustment is active. */
+                    fun planPhaseOrder(planPhaseOrder: Long?) =
+                        planPhaseOrder(JsonField.ofNullable(planPhaseOrder))
+
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: Long) =
-                        planPhaseOrder(JsonField.of(planPhaseOrder))
+                        planPhaseOrder(planPhaseOrder as Long?)
+
+                    /** The plan phase in which this adjustment is active. */
+                    @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+                    fun planPhaseOrder(planPhaseOrder: Optional<Long>) =
+                        planPhaseOrder(planPhaseOrder.orElse(null) as Long?)
 
                     /** The plan phase in which this adjustment is active. */
                     fun planPhaseOrder(planPhaseOrder: JsonField<Long>) = apply {
@@ -2670,7 +3093,10 @@ private constructor(
                     }
 
                     /** The reason for the adjustment. */
-                    fun reason(reason: String) = reason(JsonField.of(reason))
+                    fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+                    /** The reason for the adjustment. */
+                    fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
                     /** The reason for the adjustment. */
                     fun reason(reason: JsonField<String>) = apply { this.reason = reason }
@@ -2699,13 +3125,24 @@ private constructor(
 
                     fun build(): MaximumAdjustment =
                         MaximumAdjustment(
-                            id,
-                            adjustmentType,
-                            appliesToPriceIds.map { it.toImmutable() },
-                            isInvoiceLevel,
-                            maximumAmount,
-                            planPhaseOrder,
-                            reason,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(adjustmentType) {
+                                "`adjustmentType` is required but was not set"
+                            },
+                            checkNotNull(appliesToPriceIds) {
+                                    "`appliesToPriceIds` is required but was not set"
+                                }
+                                .map { it.toImmutable() },
+                            checkNotNull(isInvoiceLevel) {
+                                "`isInvoiceLevel` is required but was not set"
+                            },
+                            checkNotNull(maximumAmount) {
+                                "`maximumAmount` is required but was not set"
+                            },
+                            checkNotNull(planPhaseOrder) {
+                                "`planPhaseOrder` is required but was not set"
+                            },
+                            checkNotNull(reason) { "`reason` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -2838,19 +3275,19 @@ private constructor(
          * cycle day (e.g. billing_cycle_day=31 for April means the billing period begins on the
          * 30th.
          */
-        @JsonProperty("day") @ExcludeMissing fun _day() = day
+        @JsonProperty("day") @ExcludeMissing fun _day(): JsonField<Long> = day
 
         /**
          * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
          * February would have cycles starting February, May, August, and November).
          */
-        @JsonProperty("month") @ExcludeMissing fun _month() = month
+        @JsonProperty("month") @ExcludeMissing fun _month(): JsonField<Long> = month
 
         /**
          * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored on
          * 2021 would have cycles starting on 2021, 2023, 2025, etc.).
          */
-        @JsonProperty("year") @ExcludeMissing fun _year() = year
+        @JsonProperty("year") @ExcludeMissing fun _year(): JsonField<Long> = year
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -2876,7 +3313,7 @@ private constructor(
 
         class Builder {
 
-            private var day: JsonField<Long> = JsonMissing.of()
+            private var day: JsonField<Long>? = null
             private var month: JsonField<Long> = JsonMissing.of()
             private var year: JsonField<Long> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
@@ -2911,7 +3348,20 @@ private constructor(
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
              * February would have cycles starting February, May, August, and November).
              */
-            fun month(month: Long) = month(JsonField.of(month))
+            fun month(month: Long?) = month(JsonField.ofNullable(month))
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            fun month(month: Long) = month(month as Long?)
+
+            /**
+             * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
+             * February would have cycles starting February, May, August, and November).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun month(month: Optional<Long>) = month(month.orElse(null) as Long?)
 
             /**
              * The month on which the billing cycle is anchored (e.g. a quarterly price anchored in
@@ -2923,7 +3373,20 @@ private constructor(
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
              * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
              */
-            fun year(year: Long) = year(JsonField.of(year))
+            fun year(year: Long?) = year(JsonField.ofNullable(year))
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            fun year(year: Long) = year(year as Long?)
+
+            /**
+             * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
+             * on 2021 would have cycles starting on 2021, 2023, 2025, etc.).
+             */
+            @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+            fun year(year: Optional<Long>) = year(year.orElse(null) as Long?)
 
             /**
              * The year on which the billing cycle is anchored (e.g. a 2 year billing cycle anchored
@@ -2952,7 +3415,7 @@ private constructor(
 
             fun build(): BillingCycleAnchorConfiguration =
                 BillingCycleAnchorConfiguration(
-                    day,
+                    checkNotNull(day) { "`day` is required but was not set" },
                     month,
                     year,
                     additionalProperties.toImmutable(),
@@ -3204,25 +3667,33 @@ private constructor(
             fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
             /** Only available if discount_type is `amount`. */
-            @JsonProperty("amount_discount") @ExcludeMissing fun _amountDiscount() = amountDiscount
+            @JsonProperty("amount_discount")
+            @ExcludeMissing
+            fun _amountDiscount(): JsonField<String> = amountDiscount
 
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3251,19 +3722,21 @@ private constructor(
 
             class Builder {
 
-                private var amountDiscount: JsonField<String> = JsonMissing.of()
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var amountDiscount: JsonField<String>? = null
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(amountDiscountInterval: AmountDiscountInterval) = apply {
                     amountDiscount = amountDiscountInterval.amountDiscount
-                    appliesToPriceIds = amountDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = amountDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        amountDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        amountDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = amountDiscountInterval.discountType
                     endDate = amountDiscountInterval.endDate
                     startDate = amountDiscountInterval.startDate
@@ -3286,7 +3759,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3296,9 +3783,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3307,7 +3809,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3344,12 +3849,20 @@ private constructor(
 
                 fun build(): AmountDiscountInterval =
                     AmountDiscountInterval(
-                        amountDiscount,
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
+                        checkNotNull(amountDiscount) {
+                            "`amountDiscount` is required but was not set"
+                        },
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3472,25 +3985,31 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** Only available if discount_type is `percentage`.This is a number between 0 and 1. */
             @JsonProperty("percentage_discount")
             @ExcludeMissing
-            fun _percentageDiscount() = percentageDiscount
+            fun _percentageDiscount(): JsonField<Double> = percentageDiscount
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3519,18 +4038,22 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var percentageDiscount: JsonField<Double> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var percentageDiscount: JsonField<Double>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(percentageDiscountInterval: PercentageDiscountInterval) = apply {
-                    appliesToPriceIds = percentageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = percentageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        percentageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        percentageDiscountInterval.appliesToPriceIntervalIds.map {
+                            it.toMutableList()
+                        }
                     discountType = percentageDiscountInterval.discountType
                     endDate = percentageDiscountInterval.endDate
                     percentageDiscount = percentageDiscountInterval.percentageDiscount
@@ -3545,7 +4068,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3555,9 +4092,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3566,7 +4118,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3616,12 +4171,20 @@ private constructor(
 
                 fun build(): PercentageDiscountInterval =
                     PercentageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        percentageDiscount,
-                        startDate,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(percentageDiscount) {
+                            "`percentageDiscount` is required but was not set"
+                        },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -3747,26 +4310,34 @@ private constructor(
             /** The price ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_ids")
             @ExcludeMissing
-            fun _appliesToPriceIds() = appliesToPriceIds
+            fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
             /** The price interval ids that this discount interval applies to. */
             @JsonProperty("applies_to_price_interval_ids")
             @ExcludeMissing
-            fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+            fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
-            @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+            @JsonProperty("discount_type")
+            @ExcludeMissing
+            fun _discountType(): JsonField<DiscountType> = discountType
 
             /** The end date of the discount interval. */
-            @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+            @JsonProperty("end_date")
+            @ExcludeMissing
+            fun _endDate(): JsonField<OffsetDateTime> = endDate
 
             /** The start date of the discount interval. */
-            @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+            @JsonProperty("start_date")
+            @ExcludeMissing
+            fun _startDate(): JsonField<OffsetDateTime> = startDate
 
             /**
              * Only available if discount_type is `usage`. Number of usage units that this discount
              * is for
              */
-            @JsonProperty("usage_discount") @ExcludeMissing fun _usageDiscount() = usageDiscount
+            @JsonProperty("usage_discount")
+            @ExcludeMissing
+            fun _usageDiscount(): JsonField<Double> = usageDiscount
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -3795,18 +4366,20 @@ private constructor(
 
             class Builder {
 
-                private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-                private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-                private var discountType: JsonField<DiscountType> = JsonMissing.of()
-                private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var usageDiscount: JsonField<Double> = JsonMissing.of()
+                private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+                private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+                private var discountType: JsonField<DiscountType>? = null
+                private var endDate: JsonField<OffsetDateTime>? = null
+                private var startDate: JsonField<OffsetDateTime>? = null
+                private var usageDiscount: JsonField<Double>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(usageDiscountInterval: UsageDiscountInterval) = apply {
-                    appliesToPriceIds = usageDiscountInterval.appliesToPriceIds
-                    appliesToPriceIntervalIds = usageDiscountInterval.appliesToPriceIntervalIds
+                    appliesToPriceIds =
+                        usageDiscountInterval.appliesToPriceIds.map { it.toMutableList() }
+                    appliesToPriceIntervalIds =
+                        usageDiscountInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                     discountType = usageDiscountInterval.discountType
                     endDate = usageDiscountInterval.endDate
                     startDate = usageDiscountInterval.startDate
@@ -3820,7 +4393,21 @@ private constructor(
 
                 /** The price ids that this discount interval applies to. */
                 fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                    this.appliesToPriceIds = appliesToPriceIds
+                    this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+                }
+
+                /** The price ids that this discount interval applies to. */
+                fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                    appliesToPriceIds =
+                        (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceId)
+                        }
                 }
 
                 /** The price interval ids that this discount interval applies to. */
@@ -3830,9 +4417,24 @@ private constructor(
                 /** The price interval ids that this discount interval applies to. */
                 fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                     apply {
-                        this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                        this.appliesToPriceIntervalIds =
+                            appliesToPriceIntervalIds.map { it.toMutableList() }
                     }
 
+                /** The price interval ids that this discount interval applies to. */
+                fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                    appliesToPriceIntervalIds =
+                        (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(appliesToPriceIntervalId)
+                        }
+                }
+
                 fun discountType(discountType: DiscountType) =
                     discountType(JsonField.of(discountType))
 
@@ -3841,7 +4443,10 @@ private constructor(
                 }
 
                 /** The end date of the discount interval. */
-                fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+                fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+                /** The end date of the discount interval. */
+                fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
                 /** The end date of the discount interval. */
                 fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -3893,12 +4498,20 @@ private constructor(
 
                 fun build(): UsageDiscountInterval =
                     UsageDiscountInterval(
-                        appliesToPriceIds.map { it.toImmutable() },
-                        appliesToPriceIntervalIds.map { it.toImmutable() },
-                        discountType,
-                        endDate,
-                        startDate,
-                        usageDiscount,
+                        checkNotNull(appliesToPriceIds) {
+                                "`appliesToPriceIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(appliesToPriceIntervalIds) {
+                                "`appliesToPriceIntervalIds` is required but was not set"
+                            }
+                            .map { it.toImmutable() },
+                        checkNotNull(discountType) { "`discountType` is required but was not set" },
+                        checkNotNull(endDate) { "`endDate` is required but was not set" },
+                        checkNotNull(startDate) { "`startDate` is required but was not set" },
+                        checkNotNull(usageDiscount) {
+                            "`usageDiscount` is required but was not set"
+                        },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -4002,13 +4615,17 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+        @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-        @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+        @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Double> = quantity
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4035,10 +4652,10 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var priceId: JsonField<String> = JsonMissing.of()
-            private var quantity: JsonField<Double> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var priceId: JsonField<String>? = null
+            private var quantity: JsonField<Double>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -4050,7 +4667,9 @@ private constructor(
                 additionalProperties = fixedFeeQuantitySchedule.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -4089,10 +4708,10 @@ private constructor(
 
             fun build(): FixedFeeQuantitySchedule =
                 FixedFeeQuantitySchedule(
-                    endDate,
-                    priceId,
-                    quantity,
-                    startDate,
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(priceId) { "`priceId` is required but was not set" },
+                    checkNotNull(quantity) { "`quantity` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4162,24 +4781,30 @@ private constructor(
         /** The price ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this maximum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the maximum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The maximum amount to charge in a given billing period for the price intervals this
          * transform applies to.
          */
-        @JsonProperty("maximum_amount") @ExcludeMissing fun _maximumAmount() = maximumAmount
+        @JsonProperty("maximum_amount")
+        @ExcludeMissing
+        fun _maximumAmount(): JsonField<String> = maximumAmount
 
         /** The start date of the maximum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4207,17 +4832,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var maximumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var maximumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(maximumInterval: MaximumInterval) = apply {
-                appliesToPriceIds = maximumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = maximumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = maximumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    maximumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = maximumInterval.endDate
                 maximumAmount = maximumInterval.maximumAmount
                 startDate = maximumInterval.startDate
@@ -4230,7 +4856,21 @@ private constructor(
 
             /** The price ids that this maximum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this maximum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this maximum interval applies to. */
@@ -4240,11 +4880,29 @@ private constructor(
             /** The price interval ids that this maximum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this maximum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the maximum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the maximum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the maximum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4292,11 +4950,17 @@ private constructor(
 
             fun build(): MaximumInterval =
                 MaximumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    maximumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(maximumAmount) { "`maximumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4446,24 +5110,30 @@ private constructor(
         /** The price ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_ids")
         @ExcludeMissing
-        fun _appliesToPriceIds() = appliesToPriceIds
+        fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
         /** The price interval ids that this minimum interval applies to. */
         @JsonProperty("applies_to_price_interval_ids")
         @ExcludeMissing
-        fun _appliesToPriceIntervalIds() = appliesToPriceIntervalIds
+        fun _appliesToPriceIntervalIds(): JsonField<List<String>> = appliesToPriceIntervalIds
 
         /** The end date of the minimum interval. */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The minimum amount to charge in a given billing period for the price intervals this
          * minimum applies to.
          */
-        @JsonProperty("minimum_amount") @ExcludeMissing fun _minimumAmount() = minimumAmount
+        @JsonProperty("minimum_amount")
+        @ExcludeMissing
+        fun _minimumAmount(): JsonField<String> = minimumAmount
 
         /** The start date of the minimum interval. */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -4491,17 +5161,18 @@ private constructor(
 
         class Builder {
 
-            private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-            private var appliesToPriceIntervalIds: JsonField<List<String>> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var minimumAmount: JsonField<String> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+            private var appliesToPriceIntervalIds: JsonField<MutableList<String>>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var minimumAmount: JsonField<String>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(minimumInterval: MinimumInterval) = apply {
-                appliesToPriceIds = minimumInterval.appliesToPriceIds
-                appliesToPriceIntervalIds = minimumInterval.appliesToPriceIntervalIds
+                appliesToPriceIds = minimumInterval.appliesToPriceIds.map { it.toMutableList() }
+                appliesToPriceIntervalIds =
+                    minimumInterval.appliesToPriceIntervalIds.map { it.toMutableList() }
                 endDate = minimumInterval.endDate
                 minimumAmount = minimumInterval.minimumAmount
                 startDate = minimumInterval.startDate
@@ -4514,7 +5185,21 @@ private constructor(
 
             /** The price ids that this minimum interval applies to. */
             fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-                this.appliesToPriceIds = appliesToPriceIds
+                this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+            }
+
+            /** The price ids that this minimum interval applies to. */
+            fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+                appliesToPriceIds =
+                    (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceId)
+                    }
             }
 
             /** The price interval ids that this minimum interval applies to. */
@@ -4524,11 +5209,29 @@ private constructor(
             /** The price interval ids that this minimum interval applies to. */
             fun appliesToPriceIntervalIds(appliesToPriceIntervalIds: JsonField<List<String>>) =
                 apply {
-                    this.appliesToPriceIntervalIds = appliesToPriceIntervalIds
+                    this.appliesToPriceIntervalIds =
+                        appliesToPriceIntervalIds.map { it.toMutableList() }
                 }
 
+            /** The price interval ids that this minimum interval applies to. */
+            fun addAppliesToPriceIntervalId(appliesToPriceIntervalId: String) = apply {
+                appliesToPriceIntervalIds =
+                    (appliesToPriceIntervalIds ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(appliesToPriceIntervalId)
+                    }
+            }
+
+            /** The end date of the minimum interval. */
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
             /** The end date of the minimum interval. */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /** The end date of the minimum interval. */
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
@@ -4576,11 +5279,17 @@ private constructor(
 
             fun build(): MinimumInterval =
                 MinimumInterval(
-                    appliesToPriceIds.map { it.toImmutable() },
-                    appliesToPriceIntervalIds.map { it.toImmutable() },
-                    endDate,
-                    minimumAmount,
-                    startDate,
+                    checkNotNull(appliesToPriceIds) {
+                            "`appliesToPriceIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(appliesToPriceIntervalIds) {
+                            "`appliesToPriceIntervalIds` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(minimumAmount) { "`minimumAmount` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -4915,10 +5624,12 @@ private constructor(
          */
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("id") @ExcludeMissing fun _id() = id
+        @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
         /** The day of the month that Orb bills for this price */
-        @JsonProperty("billing_cycle_day") @ExcludeMissing fun _billingCycleDay() = billingCycleDay
+        @JsonProperty("billing_cycle_day")
+        @ExcludeMissing
+        fun _billingCycleDay(): JsonField<Long> = billingCycleDay
 
         /**
          * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -4927,7 +5638,7 @@ private constructor(
          */
         @JsonProperty("current_billing_period_end_date")
         @ExcludeMissing
-        fun _currentBillingPeriodEndDate() = currentBillingPeriodEndDate
+        fun _currentBillingPeriodEndDate(): JsonField<OffsetDateTime> = currentBillingPeriodEndDate
 
         /**
          * The start date of the current billing period. This is an inclusive timestamp; the instant
@@ -4936,13 +5647,16 @@ private constructor(
          */
         @JsonProperty("current_billing_period_start_date")
         @ExcludeMissing
-        fun _currentBillingPeriodStartDate() = currentBillingPeriodStartDate
+        fun _currentBillingPeriodStartDate(): JsonField<OffsetDateTime> =
+            currentBillingPeriodStartDate
 
         /**
          * The end date of the price interval. This is the date that Orb stops billing for this
          * price.
          */
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         /**
          * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -4950,7 +5664,8 @@ private constructor(
          */
         @JsonProperty("fixed_fee_quantity_transitions")
         @ExcludeMissing
-        fun _fixedFeeQuantityTransitions() = fixedFeeQuantityTransitions
+        fun _fixedFeeQuantityTransitions(): JsonField<List<FixedFeeQuantityTransition>> =
+            fixedFeeQuantityTransitions
 
         /**
          * The Price resource represents a price that can be billed on a subscription, resulting in
@@ -5180,13 +5895,15 @@ private constructor(
          * }
          * ```
          */
-        @JsonProperty("price") @ExcludeMissing fun _price() = price
+        @JsonProperty("price") @ExcludeMissing fun _price(): JsonField<Price> = price
 
         /**
          * The start date of the price interval. This is the date that Orb starts billing for this
          * price.
          */
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -5217,15 +5934,16 @@ private constructor(
 
         class Builder {
 
-            private var id: JsonField<String> = JsonMissing.of()
-            private var billingCycleDay: JsonField<Long> = JsonMissing.of()
-            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>> =
-                JsonMissing.of()
-            private var price: JsonField<Price> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var id: JsonField<String>? = null
+            private var billingCycleDay: JsonField<Long>? = null
+            private var currentBillingPeriodEndDate: JsonField<OffsetDateTime>? = null
+            private var currentBillingPeriodStartDate: JsonField<OffsetDateTime>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var fixedFeeQuantityTransitions:
+                JsonField<MutableList<FixedFeeQuantityTransition>>? =
+                null
+            private var price: JsonField<Price>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -5235,7 +5953,8 @@ private constructor(
                 currentBillingPeriodEndDate = priceInterval.currentBillingPeriodEndDate
                 currentBillingPeriodStartDate = priceInterval.currentBillingPeriodStartDate
                 endDate = priceInterval.endDate
-                fixedFeeQuantityTransitions = priceInterval.fixedFeeQuantityTransitions
+                fixedFeeQuantityTransitions =
+                    priceInterval.fixedFeeQuantityTransitions.map { it.toMutableList() }
                 price = priceInterval.price
                 startDate = priceInterval.startDate
                 additionalProperties = priceInterval.additionalProperties.toMutableMap()
@@ -5259,8 +5978,16 @@ private constructor(
              * instant returned is exactly the end of the billing period. Set to null if this price
              * interval is not currently active.
              */
-            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime) =
-                currentBillingPeriodEndDate(JsonField.of(currentBillingPeriodEndDate))
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: OffsetDateTime?) =
+                currentBillingPeriodEndDate(JsonField.ofNullable(currentBillingPeriodEndDate))
+
+            /**
+             * The end of the current billing period. This is an exclusive timestamp, such that the
+             * instant returned is exactly the end of the billing period. Set to null if this price
+             * interval is not currently active.
+             */
+            fun currentBillingPeriodEndDate(currentBillingPeriodEndDate: Optional<OffsetDateTime>) =
+                currentBillingPeriodEndDate(currentBillingPeriodEndDate.orElse(null))
 
             /**
              * The end of the current billing period. This is an exclusive timestamp, such that the
@@ -5276,8 +6003,17 @@ private constructor(
              * instant returned is exactly the beginning of the billing period. Set to null if this
              * price interval is not currently active.
              */
-            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime) =
-                currentBillingPeriodStartDate(JsonField.of(currentBillingPeriodStartDate))
+            fun currentBillingPeriodStartDate(currentBillingPeriodStartDate: OffsetDateTime?) =
+                currentBillingPeriodStartDate(JsonField.ofNullable(currentBillingPeriodStartDate))
+
+            /**
+             * The start date of the current billing period. This is an inclusive timestamp; the
+             * instant returned is exactly the beginning of the billing period. Set to null if this
+             * price interval is not currently active.
+             */
+            fun currentBillingPeriodStartDate(
+                currentBillingPeriodStartDate: Optional<OffsetDateTime>
+            ) = currentBillingPeriodStartDate(currentBillingPeriodStartDate.orElse(null))
 
             /**
              * The start date of the current billing period. This is an inclusive timestamp; the
@@ -5292,7 +6028,13 @@ private constructor(
              * The end date of the price interval. This is the date that Orb stops billing for this
              * price.
              */
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            /**
+             * The end date of the price interval. This is the date that Orb stops billing for this
+             * price.
+             */
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             /**
              * The end date of the price interval. This is the date that Orb stops billing for this
@@ -5305,8 +6047,16 @@ private constructor(
              * fixed fees.
              */
             fun fixedFeeQuantityTransitions(
-                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>
-            ) = fixedFeeQuantityTransitions(JsonField.of(fixedFeeQuantityTransitions))
+                fixedFeeQuantityTransitions: List<FixedFeeQuantityTransition>?
+            ) = fixedFeeQuantityTransitions(JsonField.ofNullable(fixedFeeQuantityTransitions))
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun fixedFeeQuantityTransitions(
+                fixedFeeQuantityTransitions: Optional<List<FixedFeeQuantityTransition>>
+            ) = fixedFeeQuantityTransitions(fixedFeeQuantityTransitions.orElse(null))
 
             /**
              * The fixed fee quantity transitions for this price interval. This is only relevant for
@@ -5314,7 +6064,29 @@ private constructor(
              */
             fun fixedFeeQuantityTransitions(
                 fixedFeeQuantityTransitions: JsonField<List<FixedFeeQuantityTransition>>
-            ) = apply { this.fixedFeeQuantityTransitions = fixedFeeQuantityTransitions }
+            ) = apply {
+                this.fixedFeeQuantityTransitions =
+                    fixedFeeQuantityTransitions.map { it.toMutableList() }
+            }
+
+            /**
+             * The fixed fee quantity transitions for this price interval. This is only relevant for
+             * fixed fees.
+             */
+            fun addFixedFeeQuantityTransition(
+                fixedFeeQuantityTransition: FixedFeeQuantityTransition
+            ) = apply {
+                fixedFeeQuantityTransitions =
+                    (fixedFeeQuantityTransitions ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(fixedFeeQuantityTransition)
+                    }
+            }
 
             /**
              * The Price resource represents a price that can be billed on a subscription, resulting
@@ -5776,6 +6548,71 @@ private constructor(
              */
             fun price(price: JsonField<Price>) = apply { this.price = price }
 
+            fun price(unitPrice: Price.UnitPrice) = price(Price.ofUnitPrice(unitPrice))
+
+            fun price(packagePrice: Price.PackagePrice) = price(Price.ofPackagePrice(packagePrice))
+
+            fun price(matrixPrice: Price.MatrixPrice) = price(Price.ofMatrixPrice(matrixPrice))
+
+            fun price(tieredPrice: Price.TieredPrice) = price(Price.ofTieredPrice(tieredPrice))
+
+            fun price(tieredBpsPrice: Price.TieredBpsPrice) =
+                price(Price.ofTieredBpsPrice(tieredBpsPrice))
+
+            fun price(bpsPrice: Price.BpsPrice) = price(Price.ofBpsPrice(bpsPrice))
+
+            fun price(bulkBpsPrice: Price.BulkBpsPrice) = price(Price.ofBulkBpsPrice(bulkBpsPrice))
+
+            fun price(bulkPrice: Price.BulkPrice) = price(Price.ofBulkPrice(bulkPrice))
+
+            fun price(thresholdTotalAmountPrice: Price.ThresholdTotalAmountPrice) =
+                price(Price.ofThresholdTotalAmountPrice(thresholdTotalAmountPrice))
+
+            fun price(tieredPackagePrice: Price.TieredPackagePrice) =
+                price(Price.ofTieredPackagePrice(tieredPackagePrice))
+
+            fun price(groupedTieredPrice: Price.GroupedTieredPrice) =
+                price(Price.ofGroupedTieredPrice(groupedTieredPrice))
+
+            fun price(tieredWithMinimumPrice: Price.TieredWithMinimumPrice) =
+                price(Price.ofTieredWithMinimumPrice(tieredWithMinimumPrice))
+
+            fun price(tieredPackageWithMinimumPrice: Price.TieredPackageWithMinimumPrice) =
+                price(Price.ofTieredPackageWithMinimumPrice(tieredPackageWithMinimumPrice))
+
+            fun price(packageWithAllocationPrice: Price.PackageWithAllocationPrice) =
+                price(Price.ofPackageWithAllocationPrice(packageWithAllocationPrice))
+
+            fun price(unitWithPercentPrice: Price.UnitWithPercentPrice) =
+                price(Price.ofUnitWithPercentPrice(unitWithPercentPrice))
+
+            fun price(matrixWithAllocationPrice: Price.MatrixWithAllocationPrice) =
+                price(Price.ofMatrixWithAllocationPrice(matrixWithAllocationPrice))
+
+            fun price(tieredWithProrationPrice: Price.TieredWithProrationPrice) =
+                price(Price.ofTieredWithProrationPrice(tieredWithProrationPrice))
+
+            fun price(unitWithProrationPrice: Price.UnitWithProrationPrice) =
+                price(Price.ofUnitWithProrationPrice(unitWithProrationPrice))
+
+            fun price(groupedAllocationPrice: Price.GroupedAllocationPrice) =
+                price(Price.ofGroupedAllocationPrice(groupedAllocationPrice))
+
+            fun price(groupedWithProratedMinimumPrice: Price.GroupedWithProratedMinimumPrice) =
+                price(Price.ofGroupedWithProratedMinimumPrice(groupedWithProratedMinimumPrice))
+
+            fun price(groupedWithMeteredMinimumPrice: Price.GroupedWithMeteredMinimumPrice) =
+                price(Price.ofGroupedWithMeteredMinimumPrice(groupedWithMeteredMinimumPrice))
+
+            fun price(matrixWithDisplayNamePrice: Price.MatrixWithDisplayNamePrice) =
+                price(Price.ofMatrixWithDisplayNamePrice(matrixWithDisplayNamePrice))
+
+            fun price(bulkWithProrationPrice: Price.BulkWithProrationPrice) =
+                price(Price.ofBulkWithProrationPrice(bulkWithProrationPrice))
+
+            fun price(groupedTieredPackagePrice: Price.GroupedTieredPackagePrice) =
+                price(Price.ofGroupedTieredPackagePrice(groupedTieredPackagePrice))
+
             /**
              * The start date of the price interval. This is the date that Orb starts billing for
              * this price.
@@ -5811,14 +6648,23 @@ private constructor(
 
             fun build(): PriceInterval =
                 PriceInterval(
-                    id,
-                    billingCycleDay,
-                    currentBillingPeriodEndDate,
-                    currentBillingPeriodStartDate,
-                    endDate,
-                    fixedFeeQuantityTransitions.map { it.toImmutable() },
-                    price,
-                    startDate,
+                    checkNotNull(id) { "`id` is required but was not set" },
+                    checkNotNull(billingCycleDay) {
+                        "`billingCycleDay` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodEndDate) {
+                        "`currentBillingPeriodEndDate` is required but was not set"
+                    },
+                    checkNotNull(currentBillingPeriodStartDate) {
+                        "`currentBillingPeriodStartDate` is required but was not set"
+                    },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(fixedFeeQuantityTransitions) {
+                            "`fixedFeeQuantityTransitions` is required but was not set"
+                        }
+                        .map { it.toImmutable() },
+                    checkNotNull(price) { "`price` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -5846,11 +6692,13 @@ private constructor(
 
             fun quantity(): Long = quantity.getRequired("quantity")
 
-            @JsonProperty("effective_date") @ExcludeMissing fun _effectiveDate() = effectiveDate
+            @JsonProperty("effective_date")
+            @ExcludeMissing
+            fun _effectiveDate(): JsonField<OffsetDateTime> = effectiveDate
 
-            @JsonProperty("price_id") @ExcludeMissing fun _priceId() = priceId
+            @JsonProperty("price_id") @ExcludeMissing fun _priceId(): JsonField<String> = priceId
 
-            @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+            @JsonProperty("quantity") @ExcludeMissing fun _quantity(): JsonField<Long> = quantity
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -5876,9 +6724,9 @@ private constructor(
 
             class Builder {
 
-                private var effectiveDate: JsonField<OffsetDateTime> = JsonMissing.of()
-                private var priceId: JsonField<String> = JsonMissing.of()
-                private var quantity: JsonField<Long> = JsonMissing.of()
+                private var effectiveDate: JsonField<OffsetDateTime>? = null
+                private var priceId: JsonField<String>? = null
+                private var quantity: JsonField<Long>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
@@ -5929,9 +6777,11 @@ private constructor(
 
                 fun build(): FixedFeeQuantityTransition =
                     FixedFeeQuantityTransition(
-                        effectiveDate,
-                        priceId,
-                        quantity,
+                        checkNotNull(effectiveDate) {
+                            "`effectiveDate` is required but was not set"
+                        },
+                        checkNotNull(priceId) { "`priceId` is required but was not set" },
+                        checkNotNull(quantity) { "`quantity` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -5996,11 +6846,15 @@ private constructor(
 
         fun startDate(): OffsetDateTime = startDate.getRequired("start_date")
 
-        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId() = couponId
+        @JsonProperty("coupon_id") @ExcludeMissing fun _couponId(): JsonField<String> = couponId
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
-        @JsonProperty("start_date") @ExcludeMissing fun _startDate() = startDate
+        @JsonProperty("start_date")
+        @ExcludeMissing
+        fun _startDate(): JsonField<OffsetDateTime> = startDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6026,9 +6880,9 @@ private constructor(
 
         class Builder {
 
-            private var couponId: JsonField<String> = JsonMissing.of()
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
-            private var startDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var couponId: JsonField<String>? = null
+            private var endDate: JsonField<OffsetDateTime>? = null
+            private var startDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6043,7 +6897,9 @@ private constructor(
 
             fun couponId(couponId: JsonField<String>) = apply { this.couponId = couponId }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6074,9 +6930,9 @@ private constructor(
 
             fun build(): RedeemedCoupon =
                 RedeemedCoupon(
-                    couponId,
-                    endDate,
-                    startDate,
+                    checkNotNull(couponId) { "`couponId` is required but was not set" },
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    checkNotNull(startDate) { "`startDate` is required but was not set" },
                     additionalProperties.toImmutable(),
                 )
         }
@@ -6176,7 +7032,9 @@ private constructor(
         fun endDate(): Optional<OffsetDateTime> =
             Optional.ofNullable(endDate.getNullable("end_date"))
 
-        @JsonProperty("end_date") @ExcludeMissing fun _endDate() = endDate
+        @JsonProperty("end_date")
+        @ExcludeMissing
+        fun _endDate(): JsonField<OffsetDateTime> = endDate
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -6200,7 +7058,7 @@ private constructor(
 
         class Builder {
 
-            private var endDate: JsonField<OffsetDateTime> = JsonMissing.of()
+            private var endDate: JsonField<OffsetDateTime>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
@@ -6209,7 +7067,9 @@ private constructor(
                 additionalProperties = trialInfo.additionalProperties.toMutableMap()
             }
 
-            fun endDate(endDate: OffsetDateTime) = endDate(JsonField.of(endDate))
+            fun endDate(endDate: OffsetDateTime?) = endDate(JsonField.ofNullable(endDate))
+
+            fun endDate(endDate: Optional<OffsetDateTime>) = endDate(endDate.orElse(null))
 
             fun endDate(endDate: JsonField<OffsetDateTime>) = apply { this.endDate = endDate }
 
@@ -6232,7 +7092,11 @@ private constructor(
                 keys.forEach(::removeAdditionalProperty)
             }
 
-            fun build(): TrialInfo = TrialInfo(endDate, additionalProperties.toImmutable())
+            fun build(): TrialInfo =
+                TrialInfo(
+                    checkNotNull(endDate) { "`endDate` is required but was not set" },
+                    additionalProperties.toImmutable()
+                )
         }
 
         override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUsage.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUsage.kt
index cb06cf04..4a496dc0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUsage.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/SubscriptionUsage.kt
@@ -172,7 +172,7 @@ private constructor(
 
         fun data(): List<Data> = data.getRequired("data")
 
-        @JsonProperty("data") @ExcludeMissing fun _data() = data
+        @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -196,19 +196,34 @@ private constructor(
 
         class Builder {
 
-            private var data: JsonField<List<Data>> = JsonMissing.of()
+            private var data: JsonField<MutableList<Data>>? = null
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(ungroupedSubscriptionUsage: UngroupedSubscriptionUsage) = apply {
-                data = ungroupedSubscriptionUsage.data
+                data = ungroupedSubscriptionUsage.data.map { it.toMutableList() }
                 additionalProperties =
                     ungroupedSubscriptionUsage.additionalProperties.toMutableMap()
             }
 
             fun data(data: List<Data>) = data(JsonField.of(data))
 
-            fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+            fun data(data: JsonField<List<Data>>) = apply {
+                this.data = data.map { it.toMutableList() }
+            }
+
+            fun addData(data: Data) = apply {
+                this.data =
+                    (this.data ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(data)
+                    }
+            }
 
             fun additionalProperties(additionalProperties: Map<String, JsonValue>) = apply {
                 this.additionalProperties.clear()
@@ -231,7 +246,8 @@ private constructor(
 
             fun build(): UngroupedSubscriptionUsage =
                 UngroupedSubscriptionUsage(
-                    data.map { it.toImmutable() },
+                    checkNotNull(data) { "`data` is required but was not set" }
+                        .map { it.toImmutable() },
                     additionalProperties.toImmutable()
                 )
         }
@@ -259,11 +275,15 @@ private constructor(
 
             fun viewMode(): ViewMode = viewMode.getRequired("view_mode")
 
-            @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+            @JsonProperty("billable_metric")
+            @ExcludeMissing
+            fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
-            @JsonProperty("usage") @ExcludeMissing fun _usage() = usage
+            @JsonProperty("usage") @ExcludeMissing fun _usage(): JsonField<List<Usage>> = usage
 
-            @JsonProperty("view_mode") @ExcludeMissing fun _viewMode() = viewMode
+            @JsonProperty("view_mode")
+            @ExcludeMissing
+            fun _viewMode(): JsonField<ViewMode> = viewMode
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -289,15 +309,15 @@ private constructor(
 
             class Builder {
 
-                private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-                private var usage: JsonField<List<Usage>> = JsonMissing.of()
-                private var viewMode: JsonField<ViewMode> = JsonMissing.of()
+                private var billableMetric: JsonField<BillableMetric>? = null
+                private var usage: JsonField<MutableList<Usage>>? = null
+                private var viewMode: JsonField<ViewMode>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(data: Data) = apply {
                     billableMetric = data.billableMetric
-                    usage = data.usage
+                    usage = data.usage.map { it.toMutableList() }
                     viewMode = data.viewMode
                     additionalProperties = data.additionalProperties.toMutableMap()
                 }
@@ -311,7 +331,22 @@ private constructor(
 
                 fun usage(usage: List<Usage>) = usage(JsonField.of(usage))
 
-                fun usage(usage: JsonField<List<Usage>>) = apply { this.usage = usage }
+                fun usage(usage: JsonField<List<Usage>>) = apply {
+                    this.usage = usage.map { it.toMutableList() }
+                }
+
+                fun addUsage(usage: Usage) = apply {
+                    this.usage =
+                        (this.usage ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(usage)
+                        }
+                }
 
                 fun viewMode(viewMode: ViewMode) = viewMode(JsonField.of(viewMode))
 
@@ -341,9 +376,12 @@ private constructor(
 
                 fun build(): Data =
                     Data(
-                        billableMetric,
-                        usage.map { it.toImmutable() },
-                        viewMode,
+                        checkNotNull(billableMetric) {
+                            "`billableMetric` is required but was not set"
+                        },
+                        checkNotNull(usage) { "`usage` is required but was not set" }
+                            .map { it.toImmutable() },
+                        checkNotNull(viewMode) { "`viewMode` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -366,9 +404,9 @@ private constructor(
 
                 fun name(): String = name.getRequired("name")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -393,8 +431,8 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var name: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -436,8 +474,8 @@ private constructor(
 
                     fun build(): BillableMetric =
                         BillableMetric(
-                            id,
-                            name,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -483,13 +521,17 @@ private constructor(
 
                 fun timeframeStart(): OffsetDateTime = timeframeStart.getRequired("timeframe_start")
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+                @JsonProperty("timeframe_end")
+                @ExcludeMissing
+                fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
                 @JsonProperty("timeframe_start")
                 @ExcludeMissing
-                fun _timeframeStart() = timeframeStart
+                fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -515,9 +557,9 @@ private constructor(
 
                 class Builder {
 
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-                    private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+                    private var quantity: JsonField<Double>? = null
+                    private var timeframeEnd: JsonField<OffsetDateTime>? = null
+                    private var timeframeStart: JsonField<OffsetDateTime>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -570,9 +612,13 @@ private constructor(
 
                     fun build(): Usage =
                         Usage(
-                            quantity,
-                            timeframeEnd,
-                            timeframeStart,
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(timeframeEnd) {
+                                "`timeframeEnd` is required but was not set"
+                            },
+                            checkNotNull(timeframeStart) {
+                                "`timeframeStart` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -707,11 +753,11 @@ private constructor(
         fun paginationMetadata(): Optional<PaginationMetadata> =
             Optional.ofNullable(paginationMetadata.getNullable("pagination_metadata"))
 
-        @JsonProperty("data") @ExcludeMissing fun _data() = data
+        @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Data>> = data
 
         @JsonProperty("pagination_metadata")
         @ExcludeMissing
-        fun _paginationMetadata() = paginationMetadata
+        fun _paginationMetadata(): JsonField<PaginationMetadata> = paginationMetadata
 
         @JsonAnyGetter
         @ExcludeMissing
@@ -736,23 +782,41 @@ private constructor(
 
         class Builder {
 
-            private var data: JsonField<List<Data>> = JsonMissing.of()
+            private var data: JsonField<MutableList<Data>>? = null
             private var paginationMetadata: JsonField<PaginationMetadata> = JsonMissing.of()
             private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
             @JvmSynthetic
             internal fun from(groupedSubscriptionUsage: GroupedSubscriptionUsage) = apply {
-                data = groupedSubscriptionUsage.data
+                data = groupedSubscriptionUsage.data.map { it.toMutableList() }
                 paginationMetadata = groupedSubscriptionUsage.paginationMetadata
                 additionalProperties = groupedSubscriptionUsage.additionalProperties.toMutableMap()
             }
 
             fun data(data: List<Data>) = data(JsonField.of(data))
 
-            fun data(data: JsonField<List<Data>>) = apply { this.data = data }
+            fun data(data: JsonField<List<Data>>) = apply {
+                this.data = data.map { it.toMutableList() }
+            }
+
+            fun addData(data: Data) = apply {
+                this.data =
+                    (this.data ?: JsonField.of(mutableListOf())).apply {
+                        asKnown()
+                            .orElseThrow {
+                                IllegalStateException(
+                                    "Field was set to non-list type: ${javaClass.simpleName}"
+                                )
+                            }
+                            .add(data)
+                    }
+            }
 
-            fun paginationMetadata(paginationMetadata: PaginationMetadata) =
-                paginationMetadata(JsonField.of(paginationMetadata))
+            fun paginationMetadata(paginationMetadata: PaginationMetadata?) =
+                paginationMetadata(JsonField.ofNullable(paginationMetadata))
+
+            fun paginationMetadata(paginationMetadata: Optional<PaginationMetadata>) =
+                paginationMetadata(paginationMetadata.orElse(null))
 
             fun paginationMetadata(paginationMetadata: JsonField<PaginationMetadata>) = apply {
                 this.paginationMetadata = paginationMetadata
@@ -779,7 +843,8 @@ private constructor(
 
             fun build(): GroupedSubscriptionUsage =
                 GroupedSubscriptionUsage(
-                    data.map { it.toImmutable() },
+                    checkNotNull(data) { "`data` is required but was not set" }
+                        .map { it.toImmutable() },
                     paginationMetadata,
                     additionalProperties.toImmutable(),
                 )
@@ -813,13 +878,19 @@ private constructor(
 
             fun viewMode(): ViewMode = viewMode.getRequired("view_mode")
 
-            @JsonProperty("billable_metric") @ExcludeMissing fun _billableMetric() = billableMetric
+            @JsonProperty("billable_metric")
+            @ExcludeMissing
+            fun _billableMetric(): JsonField<BillableMetric> = billableMetric
 
-            @JsonProperty("metric_group") @ExcludeMissing fun _metricGroup() = metricGroup
+            @JsonProperty("metric_group")
+            @ExcludeMissing
+            fun _metricGroup(): JsonField<MetricGroup> = metricGroup
 
-            @JsonProperty("usage") @ExcludeMissing fun _usage() = usage
+            @JsonProperty("usage") @ExcludeMissing fun _usage(): JsonField<List<Usage>> = usage
 
-            @JsonProperty("view_mode") @ExcludeMissing fun _viewMode() = viewMode
+            @JsonProperty("view_mode")
+            @ExcludeMissing
+            fun _viewMode(): JsonField<ViewMode> = viewMode
 
             @JsonAnyGetter
             @ExcludeMissing
@@ -846,17 +917,17 @@ private constructor(
 
             class Builder {
 
-                private var billableMetric: JsonField<BillableMetric> = JsonMissing.of()
-                private var metricGroup: JsonField<MetricGroup> = JsonMissing.of()
-                private var usage: JsonField<List<Usage>> = JsonMissing.of()
-                private var viewMode: JsonField<ViewMode> = JsonMissing.of()
+                private var billableMetric: JsonField<BillableMetric>? = null
+                private var metricGroup: JsonField<MetricGroup>? = null
+                private var usage: JsonField<MutableList<Usage>>? = null
+                private var viewMode: JsonField<ViewMode>? = null
                 private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                 @JvmSynthetic
                 internal fun from(data: Data) = apply {
                     billableMetric = data.billableMetric
                     metricGroup = data.metricGroup
-                    usage = data.usage
+                    usage = data.usage.map { it.toMutableList() }
                     viewMode = data.viewMode
                     additionalProperties = data.additionalProperties.toMutableMap()
                 }
@@ -876,7 +947,22 @@ private constructor(
 
                 fun usage(usage: List<Usage>) = usage(JsonField.of(usage))
 
-                fun usage(usage: JsonField<List<Usage>>) = apply { this.usage = usage }
+                fun usage(usage: JsonField<List<Usage>>) = apply {
+                    this.usage = usage.map { it.toMutableList() }
+                }
+
+                fun addUsage(usage: Usage) = apply {
+                    this.usage =
+                        (this.usage ?: JsonField.of(mutableListOf())).apply {
+                            asKnown()
+                                .orElseThrow {
+                                    IllegalStateException(
+                                        "Field was set to non-list type: ${javaClass.simpleName}"
+                                    )
+                                }
+                                .add(usage)
+                        }
+                }
 
                 fun viewMode(viewMode: ViewMode) = viewMode(JsonField.of(viewMode))
 
@@ -906,10 +992,13 @@ private constructor(
 
                 fun build(): Data =
                     Data(
-                        billableMetric,
-                        metricGroup,
-                        usage.map { it.toImmutable() },
-                        viewMode,
+                        checkNotNull(billableMetric) {
+                            "`billableMetric` is required but was not set"
+                        },
+                        checkNotNull(metricGroup) { "`metricGroup` is required but was not set" },
+                        checkNotNull(usage) { "`usage` is required but was not set" }
+                            .map { it.toImmutable() },
+                        checkNotNull(viewMode) { "`viewMode` is required but was not set" },
                         additionalProperties.toImmutable(),
                     )
             }
@@ -932,9 +1021,9 @@ private constructor(
 
                 fun name(): String = name.getRequired("name")
 
-                @JsonProperty("id") @ExcludeMissing fun _id() = id
+                @JsonProperty("id") @ExcludeMissing fun _id(): JsonField<String> = id
 
-                @JsonProperty("name") @ExcludeMissing fun _name() = name
+                @JsonProperty("name") @ExcludeMissing fun _name(): JsonField<String> = name
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -959,8 +1048,8 @@ private constructor(
 
                 class Builder {
 
-                    private var id: JsonField<String> = JsonMissing.of()
-                    private var name: JsonField<String> = JsonMissing.of()
+                    private var id: JsonField<String>? = null
+                    private var name: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1002,8 +1091,8 @@ private constructor(
 
                     fun build(): BillableMetric =
                         BillableMetric(
-                            id,
-                            name,
+                            checkNotNull(id) { "`id` is required but was not set" },
+                            checkNotNull(name) { "`name` is required but was not set" },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1044,9 +1133,13 @@ private constructor(
 
                 fun propertyValue(): String = propertyValue.getRequired("property_value")
 
-                @JsonProperty("property_key") @ExcludeMissing fun _propertyKey() = propertyKey
+                @JsonProperty("property_key")
+                @ExcludeMissing
+                fun _propertyKey(): JsonField<String> = propertyKey
 
-                @JsonProperty("property_value") @ExcludeMissing fun _propertyValue() = propertyValue
+                @JsonProperty("property_value")
+                @ExcludeMissing
+                fun _propertyValue(): JsonField<String> = propertyValue
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1071,8 +1164,8 @@ private constructor(
 
                 class Builder {
 
-                    private var propertyKey: JsonField<String> = JsonMissing.of()
-                    private var propertyValue: JsonField<String> = JsonMissing.of()
+                    private var propertyKey: JsonField<String>? = null
+                    private var propertyValue: JsonField<String>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1119,8 +1212,12 @@ private constructor(
 
                     fun build(): MetricGroup =
                         MetricGroup(
-                            propertyKey,
-                            propertyValue,
+                            checkNotNull(propertyKey) {
+                                "`propertyKey` is required but was not set"
+                            },
+                            checkNotNull(propertyValue) {
+                                "`propertyValue` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
@@ -1166,13 +1263,17 @@ private constructor(
 
                 fun timeframeStart(): OffsetDateTime = timeframeStart.getRequired("timeframe_start")
 
-                @JsonProperty("quantity") @ExcludeMissing fun _quantity() = quantity
+                @JsonProperty("quantity")
+                @ExcludeMissing
+                fun _quantity(): JsonField<Double> = quantity
 
-                @JsonProperty("timeframe_end") @ExcludeMissing fun _timeframeEnd() = timeframeEnd
+                @JsonProperty("timeframe_end")
+                @ExcludeMissing
+                fun _timeframeEnd(): JsonField<OffsetDateTime> = timeframeEnd
 
                 @JsonProperty("timeframe_start")
                 @ExcludeMissing
-                fun _timeframeStart() = timeframeStart
+                fun _timeframeStart(): JsonField<OffsetDateTime> = timeframeStart
 
                 @JsonAnyGetter
                 @ExcludeMissing
@@ -1198,9 +1299,9 @@ private constructor(
 
                 class Builder {
 
-                    private var quantity: JsonField<Double> = JsonMissing.of()
-                    private var timeframeEnd: JsonField<OffsetDateTime> = JsonMissing.of()
-                    private var timeframeStart: JsonField<OffsetDateTime> = JsonMissing.of()
+                    private var quantity: JsonField<Double>? = null
+                    private var timeframeEnd: JsonField<OffsetDateTime>? = null
+                    private var timeframeStart: JsonField<OffsetDateTime>? = null
                     private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
                     @JvmSynthetic
@@ -1253,9 +1354,13 @@ private constructor(
 
                     fun build(): Usage =
                         Usage(
-                            quantity,
-                            timeframeEnd,
-                            timeframeStart,
+                            checkNotNull(quantity) { "`quantity` is required but was not set" },
+                            checkNotNull(timeframeEnd) {
+                                "`timeframeEnd` is required but was not set"
+                            },
+                            checkNotNull(timeframeStart) {
+                                "`timeframeStart` is required but was not set"
+                            },
                             additionalProperties.toImmutable(),
                         )
                 }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscriptions.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscriptions.kt
index 2a3ee645..69e4c1b7 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscriptions.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/Subscriptions.kt
@@ -33,11 +33,11 @@ private constructor(
     fun paginationMetadata(): PaginationMetadata =
         paginationMetadata.getRequired("pagination_metadata")
 
-    @JsonProperty("data") @ExcludeMissing fun _data() = data
+    @JsonProperty("data") @ExcludeMissing fun _data(): JsonField<List<Subscription>> = data
 
     @JsonProperty("pagination_metadata")
     @ExcludeMissing
-    fun _paginationMetadata() = paginationMetadata
+    fun _paginationMetadata(): JsonField<PaginationMetadata> = paginationMetadata
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -62,20 +62,35 @@ private constructor(
 
     class Builder {
 
-        private var data: JsonField<List<Subscription>> = JsonMissing.of()
-        private var paginationMetadata: JsonField<PaginationMetadata> = JsonMissing.of()
+        private var data: JsonField<MutableList<Subscription>>? = null
+        private var paginationMetadata: JsonField<PaginationMetadata>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
         internal fun from(subscriptions: Subscriptions) = apply {
-            data = subscriptions.data
+            data = subscriptions.data.map { it.toMutableList() }
             paginationMetadata = subscriptions.paginationMetadata
             additionalProperties = subscriptions.additionalProperties.toMutableMap()
         }
 
         fun data(data: List<Subscription>) = data(JsonField.of(data))
 
-        fun data(data: JsonField<List<Subscription>>) = apply { this.data = data }
+        fun data(data: JsonField<List<Subscription>>) = apply {
+            this.data = data.map { it.toMutableList() }
+        }
+
+        fun addData(data: Subscription) = apply {
+            this.data =
+                (this.data ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(data)
+                }
+        }
 
         fun paginationMetadata(paginationMetadata: PaginationMetadata) =
             paginationMetadata(JsonField.of(paginationMetadata))
@@ -105,8 +120,11 @@ private constructor(
 
         fun build(): Subscriptions =
             Subscriptions(
-                data.map { it.toImmutable() },
-                paginationMetadata,
+                checkNotNull(data) { "`data` is required but was not set" }
+                    .map { it.toImmutable() },
+                checkNotNull(paginationMetadata) {
+                    "`paginationMetadata` is required but was not set"
+                },
                 additionalProperties.toImmutable(),
             )
     }
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingParams.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingParams.kt
index 1ec61824..958b0db0 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingParams.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingParams.kt
@@ -7,6 +7,13 @@ import com.withorb.api.core.http.Headers
 import com.withorb.api.core.http.QueryParams
 import java.util.Objects
 
+/**
+ * This endpoint allows you to test your connection to the Orb API and check the validity of your
+ * API key, passed in the Authorization header. This is particularly useful for checking that your
+ * environment is set up properly, and is a great choice for connectors and integrations.
+ *
+ * This API does not have any side-effects or return any Orb resources.
+ */
 class TopLevelPingParams
 constructor(
     private val additionalHeaders: Headers,
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingResponse.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingResponse.kt
index b02f1abc..58a7dd76 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingResponse.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/TopLevelPingResponse.kt
@@ -27,7 +27,7 @@ private constructor(
 
     fun response(): String = response.getRequired("response")
 
-    @JsonProperty("response") @ExcludeMissing fun _response() = response
+    @JsonProperty("response") @ExcludeMissing fun _response(): JsonField<String> = response
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -51,7 +51,7 @@ private constructor(
 
     class Builder {
 
-        private var response: JsonField<String> = JsonMissing.of()
+        private var response: JsonField<String>? = null
         private var additionalProperties: MutableMap<String, JsonValue> = mutableMapOf()
 
         @JvmSynthetic
@@ -84,7 +84,10 @@ private constructor(
         }
 
         fun build(): TopLevelPingResponse =
-            TopLevelPingResponse(response, additionalProperties.toImmutable())
+            TopLevelPingResponse(
+                checkNotNull(response) { "`response` is required but was not set" },
+                additionalProperties.toImmutable()
+            )
     }
 
     override fun equals(other: Any?): Boolean {
diff --git a/orb-java-core/src/main/kotlin/com/withorb/api/models/TrialDiscount.kt b/orb-java-core/src/main/kotlin/com/withorb/api/models/TrialDiscount.kt
index b3d2a3cd..4e7023af 100644
--- a/orb-java-core/src/main/kotlin/com/withorb/api/models/TrialDiscount.kt
+++ b/orb-java-core/src/main/kotlin/com/withorb/api/models/TrialDiscount.kt
@@ -64,21 +64,23 @@ private constructor(
      */
     @JsonProperty("applies_to_price_ids")
     @ExcludeMissing
-    fun _appliesToPriceIds() = appliesToPriceIds
+    fun _appliesToPriceIds(): JsonField<List<String>> = appliesToPriceIds
 
-    @JsonProperty("discount_type") @ExcludeMissing fun _discountType() = discountType
+    @JsonProperty("discount_type")
+    @ExcludeMissing
+    fun _discountType(): JsonField<DiscountType> = discountType
 
-    @JsonProperty("reason") @ExcludeMissing fun _reason() = reason
+    @JsonProperty("reason") @ExcludeMissing fun _reason(): JsonField<String> = reason
 
     /** Only available if discount_type is `trial` */
     @JsonProperty("trial_amount_discount")
     @ExcludeMissing
-    fun _trialAmountDiscount() = trialAmountDiscount
+    fun _trialAmountDiscount(): JsonField<String> = trialAmountDiscount
 
     /** Only available if discount_type is `trial` */
     @JsonProperty("trial_percentage_discount")
     @ExcludeMissing
-    fun _trialPercentageDiscount() = trialPercentageDiscount
+    fun _trialPercentageDiscount(): JsonField<Double> = trialPercentageDiscount
 
     @JsonAnyGetter
     @ExcludeMissing
@@ -106,8 +108,8 @@ private constructor(
 
     class Builder {
 
-        private var appliesToPriceIds: JsonField<List<String>> = JsonMissing.of()
-        private var discountType: JsonField<DiscountType> = JsonMissing.of()
+        private var appliesToPriceIds: JsonField<MutableList<String>>? = null
+        private var discountType: JsonField<DiscountType>? = null
         private var reason: JsonField<String> = JsonMissing.of()
         private var trialAmountDiscount: JsonField<String> = JsonMissing.of()
         private var trialPercentageDiscount: JsonField<Double> = JsonMissing.of()
@@ -115,7 +117,7 @@ private constructor(
 
         @JvmSynthetic
         internal fun from(trialDiscount: TrialDiscount) = apply {
-            appliesToPriceIds = trialDiscount.appliesToPriceIds
+            appliesToPriceIds = trialDiscount.appliesToPriceIds.map { it.toMutableList() }
             discountType = trialDiscount.discountType
             reason = trialDiscount.reason
             trialAmountDiscount = trialDiscount.trialAmountDiscount
@@ -135,7 +137,24 @@ private constructor(
          * be a subset of prices.
          */
         fun appliesToPriceIds(appliesToPriceIds: JsonField<List<String>>) = apply {
-            this.appliesToPriceIds = appliesToPriceIds
+            this.appliesToPriceIds = appliesToPriceIds.map { it.toMutableList() }
+        }
+
+        /**
+         * List of price_ids that this discount applies to. For plan/plan phase discounts, this can
+         * be a subset of prices.
+         */
+        fun addAppliesToPriceId(appliesToPriceId: String) = apply {
+            appliesToPriceIds =
+                (appliesToPriceIds ?: JsonField.of(mutableListOf())).apply {
+                    asKnown()
+                        .orElseThrow {
+                            IllegalStateException(
+                                "Field was set to non-list type: ${javaClass.simpleName}"
+                            )
+                        }
+                        .add(appliesToPriceId)
+                }
         }
 
         fun discountType(discountType: DiscountType) = discountType(JsonField.of(discountType))
@@ -144,22 +163,37 @@ private constructor(
             this.discountType = discountType
         }
 
-        fun reason(reason: String) = reason(JsonField.of(reason))
+        fun reason(reason: String?) = reason(JsonField.ofNullable(reason))
+
+        fun reason(reason: Optional<String>) = reason(reason.orElse(null))
 
         fun reason(reason: JsonField<String>) = apply { this.reason = reason }
 
         /** Only available if discount_type is `trial` */
-        fun trialAmountDiscount(trialAmountDiscount: String) =
-            trialAmountDiscount(JsonField.of(trialAmountDiscount))
+        fun trialAmountDiscount(trialAmountDiscount: String?) =
+            trialAmountDiscount(JsonField.ofNullable(trialAmountDiscount))
+
+        /** Only available if discount_type is `trial` */
+        fun trialAmountDiscount(trialAmountDiscount: Optional<String>) =
+            trialAmountDiscount(trialAmountDiscount.orElse(null))
 
         /** Only available if discount_type is `trial` */
         fun trialAmountDiscount(trialAmountDiscount: JsonField<String>) = apply {
             this.trialAmountDiscount = trialAmountDiscount
         }
 
+        /** Only available if discount_type is `trial` */
+        fun trialPercentageDiscount(trialPercentageDiscount: Double?) =
+            trialPercentageDiscount(JsonField.ofNullable(trialPercentageDiscount))
+
         /** Only available if discount_type is `trial` */
         fun trialPercentageDiscount(trialPercentageDiscount: Double) =
-            trialPercentageDiscount(JsonField.of(trialPercentageDiscount))
+            trialPercentageDiscount(trialPercentageDiscount as Double?)
+
+        /** Only available if discount_type is `trial` */
+        @Suppress("USELESS_CAST") // See https://youtrack.jetbrains.com/issue/KT-74228
+        fun trialPercentageDiscount(trialPercentageDiscount: Optional<Double>) =
+            trialPercentageDiscount(trialPercentageDiscount.orElse(null) as Double?)
 
         /** Only available if discount_type is `trial` */
         fun trialPercentageDiscount(trialPercentageDiscount: JsonField<Double>) = apply {
@@ -187,8 +221,11 @@ private constructor(
 
         fun build(): TrialDiscount =
             TrialDiscount(
-                appliesToPriceIds.map { it.toImmutable() },
-                discountType,
+                checkNotNull(appliesToPriceIds) {
+                        "`appliesToPriceIds` is required but was not set"
+                    }
+                    .map { it.toImmutable() },
+                checkNotNull(discountType) { "`discountType` is required but was not set" },
                 reason,
                 trialAmountDiscount,
                 trialPercentageDiscount,
diff --git a/orb-java-core/src/test/kotlin/com/withorb/api/models/EventUpdateParamsTest.kt b/orb-java-core/src/test/kotlin/com/withorb/api/models/EventUpdateParamsTest.kt
index 0108244c..5883b628 100644
--- a/orb-java-core/src/test/kotlin/com/withorb/api/models/EventUpdateParamsTest.kt
+++ b/orb-java-core/src/test/kotlin/com/withorb/api/models/EventUpdateParamsTest.kt
@@ -35,7 +35,7 @@ class EventUpdateParamsTest {
         val body = params.getBody()
         assertThat(body).isNotNull
         assertThat(body.eventName()).isEqualTo("event_name")
-        assertThat(body.properties()).isEqualTo(JsonValue.from(mapOf<String, Any>()))
+        assertThat(body._properties()).isEqualTo(JsonValue.from(mapOf<String, Any>()))
         assertThat(body.timestamp()).isEqualTo(OffsetDateTime.parse("2020-12-09T16:09:53Z"))
         assertThat(body.customerId()).contains("customer_id")
         assertThat(body.externalCustomerId()).contains("external_customer_id")
@@ -53,7 +53,7 @@ class EventUpdateParamsTest {
         val body = params.getBody()
         assertThat(body).isNotNull
         assertThat(body.eventName()).isEqualTo("event_name")
-        assertThat(body.properties()).isEqualTo(JsonValue.from(mapOf<String, Any>()))
+        assertThat(body._properties()).isEqualTo(JsonValue.from(mapOf<String, Any>()))
         assertThat(body.timestamp()).isEqualTo(OffsetDateTime.parse("2020-12-09T16:09:53Z"))
     }
 
diff --git a/orb-java-core/src/test/kotlin/com/withorb/api/models/MetricCreateParamsTest.kt b/orb-java-core/src/test/kotlin/com/withorb/api/models/MetricCreateParamsTest.kt
index afe703c9..92fe23db 100644
--- a/orb-java-core/src/test/kotlin/com/withorb/api/models/MetricCreateParamsTest.kt
+++ b/orb-java-core/src/test/kotlin/com/withorb/api/models/MetricCreateParamsTest.kt
@@ -56,12 +56,14 @@ class MetricCreateParamsTest {
     fun getBodyWithoutOptionalFields() {
         val params =
             MetricCreateParams.builder()
+                .description("Sum of bytes downloaded in fast mode")
                 .itemId("item_id")
                 .name("Bytes downloaded")
                 .sql("SELECT sum(bytes_downloaded) FROM events WHERE download_speed = 'fast'")
                 .build()
         val body = params.getBody()
         assertThat(body).isNotNull
+        assertThat(body.description()).contains("Sum of bytes downloaded in fast mode")
         assertThat(body.itemId()).isEqualTo("item_id")
         assertThat(body.name()).isEqualTo("Bytes downloaded")
         assertThat(body.sql())